Answer:
See explanation
Explanation:
9) If an extra electron is added to the neon atom, then the electronic configuration becomes; 1s2 2s2 2p6 3s1
This last electron has quantum numbers;
n=3, l=0, m=0 and s = +1/2
This is so because the 2s level is already filled so the extra electron must go into the 3s level. The orbital quantum number and the magnetic quantum number for the s orbital is zero.
10) Electron affinity is the energy released when one mole of gaseous atoms accept one mole of gaseous electrons to form one mole of gaseous ions having a negative charge.
In the second period, fluorine has the greatest electron affinity since electron affinity increases across the period. The noble gas, neon has an electron affinity of 0KJ/mol.
11) Ionization energy decreases down the group but increases across the period due to increase in the size of the nuclear charge and decrease in the distance between the nucleus and the outermost electron. Hence, the process; Br+(g) ---->Br2+(g) + e- has the greatest ionization energy. Recall that the second ionization is always higher than the first ionization energy.
12)The order of decreasing metallic character here is K> As> P. Even though As and P belong to the same group, we must note that metallic character increases down the group hence the order written above.
The normal freezing point of a certain liquid Xis-7.30°C but when l02. g of iron(III) chloride (FeCl3) are dissolved in 650. g of Xthe solution freezes at -9.9°C instead. Use this information to calculate the molal freezing point depression constant Kf of X.
Answer:
2.7 °C.kg/mol
Explanation:
Step 1: Calculate the freezing point depression (ΔT)
The normal freezing point of a certain liquid X is-7.30°C and the solution freezes at -9.9°C instead. The freezing point depression is:
ΔT = -7.30 °C - (-9.9 °C) = 2.6 °C
Step 2: Calculate the molality of the solution (b)
We will use the following expression.
b = mass of solute / molar mass of solute × kilograms of solvent
b = 102. g / (162.2 g/mol) × 0.650 kg = 0.967 mol/kg
Step 3: Calculate the molal freezing point depression constant Kf of X
Freezing point depression is a colligative property. It can be calculated using the following expression.
ΔT = Kf × b
Kf = ΔT / b
Kf = 2.6 °C / (0.967 mol/kg) = 2.7 °C.kg/mol
Select the keyword or phrase that will best complete each sentence. law is a gas law that relates pressure and volume and states that for a fixed amount of gas at constant temperature, the pressure and volume of the gas are ____________ related. ____________ law is a gas law that states that for a fixed amount of gas at constant pressure, the volume of the gas is propotional to its Kelvin temperature. ____________ law is a law that states that the total pressure of a gas mixture is equal to the sum of the partial pressure of its component gases. ____________ law is a gas law that states that the volume of a gas is ____________ proportional to the number of moles of present when the pressure and temperature are held constant. ____________ law is a gas law that states for a fixed amount of gas at constant volume, the pressure of the gas is ____________ proportional to its Kelvin temperature. The ____________ law is a gas law that relates pressure, volume, and temperature. The ____________ law is the equation PV
Answer:
Find answers below.
Explanation:
1. Boyle's law is a gas law that relates pressure and volume and states that for a fixed amount of gas at constant temperature, the pressure and volume of the gas are directly related.
Mathematically, Boyle's law is given by;
[tex] PV = K[/tex]
[tex] P_{1}V_{1} = P_{2}V_{2} [/tex]
Where;
P1 and P2 represents the initial and final pressures respectively.
V1 and V2 represents the initial and final volumes respectively.
2. Charles law is a gas law that states that for a fixed amount of gas at constant pressure, the volume of the gas is propotional to its Kelvin temperature.
Mathematically, Charles is given by;
[tex] VT = K[/tex]
[tex] \frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}[/tex]
Where;
V1 and V2 represents the initial and final volumes respectively.
T1 and T2 represents the initial and final temperatures respectively.
3. Dalton law is a law that states that the total pressure of a gas mixture is equal to the sum of the partial pressure of its component gases.
4. Avogadro's law is a gas law that states that the volume of a gas is directly proportional to the number of moles of present when the pressure and temperature are held constant.
5. Gay Lussac's law is a gas law that states for a fixed amount of gas at constant volume, the pressure of the gas is directly proportional to its Kelvin temperature.
Mathematically, Gay Lussac's law is given by;
[tex] PT = K[/tex]
[tex] \frac{P1}{T1} = \frac{P2}{T2}[/tex]
6. The combined gas law is a gas law that relates pressure, volume, and temperature.
7. The ideal gas law is the equation PV = nRT
Where;
P is the pressure.
V is the volume.
n is the number of moles of substance.
R is the ideal gas constant.
T is the temperature.
How does the behavior of a high-energy particle compare to a low-energy particle?
Answer:
The problem of energy exchange between waves and particles, which leads to energization of the latter, in an unstable plasma typical of the radiation belts. The ongoing Van Allen Probes space mission brought this problem among the most discussed in space physics. A free energy which is present in an unstable plasma provides the indispensable condition for energy transfer from lower energy particles to higher-energy particles via resonant wave-particle interaction. This process is studied in detail by the example of electron interactions with whistler mode wave packets originated from lightning-induced emission. We emphasize that in an unstable plasma, the energy source for electron energization is the energy of other particles, rather than the wave energy as is often assumed. The way by which the energy is transferred from lower energy to higher-energy particles includes two processes that operate concurrently, in the same space-time domain, or sequentially, in different space-time domains, in which a given wave packet is located. In the first process, one group of resonant particles gives the energy to the wave. The second process consists in wave absorption by another group of resonant particles, whose energy therefore increases. We argue that this mechanism represents an efficient means of electron energization in the radiation belts.
Explanation:
Fun facts:
In the process of energy transfer between two groups of particles both processes operate simultaneously, and if the lower energy part of plasma distribution gives energy to the wave while the higher‐energy part absorbs the wave enrgy, then the wave‐mediated energy transfer from lower energy particles to higher‐energy ...
What does the rate law tell you about a reaction?
A. How the concentration of the reactants affects the rate of a
reaction
B. How temperature affects the rate of a reaction
C. How the equilibrium constant is related to the rate of a reaction
D. How the rate of a reaction affects the total time of a reaction
Answer:
A. How the concentration of the reactants affects the rate of a reaction
Explanation:
Let's consider a generic reaction.
A + B ⇒ Products
The generic rate law is:
rate = k × [A]ᵃ × [B]ᵇ
where,
rate: rate of the reaction[A] and [B]: molar concentrations of the reactantsk: rate constanta and b: reaction ordersAs we can see, the rate law shows how the concentration of the reactants affects the rate of a reaction.
hợp chất nào có khả năng là hợp chất ion cao nhất ?
A Al2O3
B ScCl3
C NO2
D CCl4
Answer:
B
Explanation:
hợp chất nào có khả năng là hợp chất ion cao nhất ?
A Al2O3?
B
A certain first-order reaction is 45.0% complete in 65 s. What are the values of the rate constant and the half-life for this process
Answer:
0.01228s⁻¹ = rate constant
Half-life = 56.4s
Explanation:
The first order reaction follows the equation:
ln[A] = -kt + ln[A]₀
Where [A] is amount of reactant after time t = 45.0%, k is rate constante and [A]₀ initial amount of reactant = 100%
ln[45%] = -k*65s + ln[100%]
-0.7985 = -k*65s
0.01228s⁻¹ = rate constant
Half-life is:
Half-life = ln2 / k
Half-life = 56.4s
Balance this equation, _AlCl3 + _NaOH → _Al(OH)3 + _NaCl
Answer:
AlCl3 + 3NaOH ———>Al(OH)3 + 3NaCl
Draw the structures and provide the names of all the isomeric alcohols that have the molecular formula C4H10O Draw the structures of (a) 6-methyl-3-heptanol and (b) trans-2-methylcyclohexanol
Answer:
Draw the structures and provide the names of all the isomeric alcohols that have the molecular formula C4H10O.
Draw the structures of (a) 6-methyl-3-heptanol and (b) trans-2-methylcyclohexanol
Explanation:
Isomers are compounds with the same molecular formula but different structural arrangements of atoms.
The given molecule is:
C4H10O.
The possible isomeric alcohols structures are shown below:
Structure of (a) 6-methyl-3-heptanol:
The root word -hept indicates that the main carbon chain has seven carbons.
-ol suffix indicates the presence of alcohol functional group at third carbon.
The 6-methyl prefix indicates the presence of methyl group as the substituent at the sixth position of the main carbon chain.
The structure of 6-methyl-3-heptanol is shown below:
The structure of trans-2-methyl cyclohexanol is shown below:
The pH of a certain orange juice is 3.33.Calculate the +ion concentration.
Answer:
[tex]4.67\times 10^{-4}[/tex]
Explanation:
Given that,
The pH of a certain orange juice is 3.33.
We need to find the +ion concentration.
We know that,
[tex]pH=-log[H^+][/tex]
So,
[tex]3.33=-log[H^+]\\\\\[H^+=10^{-3.33}\\\\=4.67\times 10^{-4}[/tex]
So, the +ion concentraion is equal to [tex]4.67\times 10^{-4}[/tex].
Astatine is a halogen with several isotopes that all have short half-lives. Which of the following combinations of mass number and neutrons are possible as isotopes of astatine? Choose one or more:
i) A = 211, n = 127
ii) A = 210, n = 125
iii) A = 220, n = 134
iv) A = 207, n = 122
v) A = 209, n = 124
Answer:
Astatine is a halogen with several isotopes that all have short half-lives.
Which of the following combinations of mass number and neutrons are possible as isotopes of astatine? Choose one or more:
i) A = 211, n = 127
ii) A = 210, n = 125
iii) A = 220, n = 134
iv) A = 207, n = 122
v) A = 209, n = 124
Explanation:
The mass number is the sum of the number of protons and the number of neutrons in an atom.[tex]A=no.of protons+no.of neutrons\\=>no.of neutrons=A-no.of protons\\[/tex]
Atomic number of At(astatine ) =85
That means it has --- 85protons.
Its mass number A=210
Hence, the number of neutrons in At are:
[tex]n=A-Z\\=>n=210-85\\=>n=125[/tex]
Second option:
ii) A=210 , n=125 is the answer.
An atom of 24/11 na decays by gamma decay which atom is left after the decay
Answer:
Hello There!!
Explanation:
The atom is still 24Na.
hope this helps,have a great day!!
~Pinky~
A buffer solution contains 0.298 M ammonium chloride and 0.478 M ammonia. If 0.0560 moles of hydroiodic acid are added to 225 mL of this buffer, what is the pH of the resulting solution?
Answer:
pH = 8.87
Explanation:
Hydroiodic acid, HI, is a strong acid that reacts with ammonia, NH3, to produce ammonium ion, NH⁴⁺. That means the moles of HI added = moles of NH3 consumed and moles of NH4⁺ produced.
Initial moles NH₄⁺:
0.225L * (0.298mol/L) = 0.06705 moles
Initial moles NH3:
0.225L * (0.478mol/L) = 0.10755 moles
After the reaction the moles are:
0.10755moles NH3 - 0.0560moles = 0.05155 moles NH3
0.06705moles NH4+ + 0.0560moles = 0.12305 moles NH4+
Using H-H equation for weak bases:
pOH = pKb + log ([NH4+] / [NH3])
pKb for ammonia is 4.75, [NH4+] could be the moles of NH4+ = 0.12305mol,
[NH3] = 0.05155moles
Replacing:
pOH = 4.75 + log (0.12305mol / 0.05155moles)
pOH = 5.13
pH = 14-pOH
pH = 8.87Complete the sentence.
Hexene would have _ carbon atoms and one _ bond
First blank options:
7, 8, 1, 2, 4, 3, 5, 6
Second blank options:
single, double, triple
Answer:
6, double
Explanation:
Hex- is a prefix for number 6.
Ene- is a suffix for a double bond.
Explain Boyle's pressure-volume relationship in terms of the kinetic-
molecular theory.
.
Answer:
The pressure and the volume are inversely related in Boyle's Law. In Kinetic theory pressure is created by the collision of particles. If the volume is greater the number of collisions and pressure will be less. So volume and pressure are inversely related if the temperature and total kinetic energy is kept constant.
Explanation:
hope to help you
Chlorine gas can be prepared in the laboratory by the reaction of hydrochloric acid with manganese(IV) oxide.
4HCl(aq)+MnO2(s)⟶MnCl2(aq)+2H2O(l)+Cl2(g)
A sample of 43.1g MnO2 is added to a solution containing 42.9g HCl.
a. What is the limiting agent?
b. What is the theoretical yield of Cl2?
c. If the yield of the reaction is 72.9%, what is the actual yield of chlorine?
Answer:
A. HCl is the limiting reactant.
B. Theoretical yield of Cl₂ is 20.9 g.
C. Actual yield of Cl₂ = 15.2 g.
Explanation:
The balanced equation for the reaction is given below:
4HCl + MnO₂ –> MnCl₂ + 2H₂O + Cl₂
Next, we shall determine the masses of HCl and MnO₂ that reacted and the mass of Cl₂ produced from the balanced equation. This can be obtained as follow:
Molar mass of HCl = 1 + 35.5
= 36.5 g/mol
Mass of HCl from the balanced equation = 4 × 36.5 = 146 g
Molar mass of MnO₂ = 55 + (2×16)
= 55 + 32
= 87 g/mol
Mass of MnO₂ from the balanced equation = 1 × 87 = 87 g
Molar mass of Cl₂ = 2 × 35.5
= 71 g/mol
Mass of Cl₂ from the balanced equation = 1 × 71 = 71 g
SUMMARY:
From the balanced equation above,
146 g of HCl reacted with 87 g of MnO₂ to produce 71 g of Cl₂.
A. Determination of the limiting reactant.
From the balanced equation above,
146 g of HCl reacted with 87 g of MnO₂.
Therefore, 42.9 g of HCl will react with = (42.9 × 87)/146 = 25.6 g of MnO₂.
From the calculation made above, we can see clearly that only 25.6 g out of 43.1 g of MnO₂ given was needed to react completely with 42.9 g of HCl.
Therefore, HCl is the limiting reactant.
B. Determination of theoretical yield of Cl₂.
Here, the limiting reactant will be used.
From the balanced equation above,
146 g of HCl reacted to produce 71 g of Cl₂.
Therefore, 42.9 g of HCl will react to produce = (42.9 × 71)/146 = 20.9 g of Cl₂.
Thus, the theoretical yield of Cl₂ is 20.9 g.
C. Determination of the actual yield of Cl₂.
Theoretical yield of Cl₂ = 20.9 g
Percentage yield of Cl₂ = 72.9%
Actual yield of Cl₂ =?
Percentage yield = Actual yield / Theoretical yield × 100
72.9% = Actual yield / 20.9
Cross multiply
Actual yield = 72.9% × 20.9
Actual yield = 72.9/100 × 20.9
Actual yield = 0.729 × 20.9
Actual yield of Cl₂ = 15.2 g
A buffer solution contains 0.472 M hydrocyanic acid and 0.342 M sodium cyanide. If 0.0194 moles of sodium hydroxide are added to 150 mL of this buffer, what is the pH of the resulting solution
Answer:
pH = 9.54.
Explanation:
Hello there!
In this case, since this is an acidic buffer due to the hydrocyanic acid, it will be firstly necessary for us to calculate the moles of both acid and conjugate base in 150 mL given their concentrations:
[tex]n_{acid}=0.472mol/L*0.150L=0.0708mol\\\\n_{base}=0.342mol/L*0.150L=0.0513mol[/tex]
Next, since the effect of adding NaOH, consume the acid and produce more base, we subtract 0.0194 moles from 0.0708 mol and add 0.0194 to 0.0513 mol for us to calculate the new moles:
[tex]n_{acid}^{new}=0.0708mol-0.0194mol=0.0514mol\\\\n_{base}^{new}=0.0513mol+0.0194mol=0.0707mol[/tex]
Thus, since the pKa of hydrocyanic acid is 9.40, we therefore use the Henderson-Hasselbach equation to calculate the pH of the resulting solution for the same volume:
[tex]pH=9.40+log(\frac{0.0707mol}{0.0514mol} )\\\\pH=9.54[/tex]
Which increase make sense since we added some strong base.
Regards!
The products in a decomposition reaction _____. are compounds can be elements or compounds are elements include an element and a compound
Answer:
compounds are elements include an element and a compound
Explanation:
elements in the decomposition reaction is the substance that cannot be separated into simpler substances. Compounds, technically act as a reactant in the decomposition reaction, but since the reaction breakdown one substance into two or more, sometimes it exists in the product
Which of the following is the most plausible explanation for the fact that the saponification of the triacylglycerol in the passage resulted in four different fatty acid salts?
a. The triacylglycerol molecule consisted of four different fatty acid units.
b. Glycerol was transformed into a fatty acid salt under the reaction conditions.
c. One of the fatty acid salts was unsaturated, and it completely isomerized under the reaction conditions.
d. One of the fatty acid salts was unsaturated, and a small percentage isomerized under the reaction conditions.
Answer: The correct option is C (One of the fatty acid salts was unsaturated, and it completely isomerized under the reaction conditions).
Explanation:
Fats and oils belongs to a general group of compounds known as lipids. Fatty acids are weak acid and are divided into two:
--> Saturated fatty acids: These have NO double bonds in their hydrocarbon chain, and
--> Unsaturated fatty acids: These have one or more double bonds in their hydrocarbon chain.
SAPONIFICATION is defined as the process by which fats and oil is hydrolyzed with caustic alkali to yield propane-1,2,3-triol and the corresponding sodium salt of the component fatty acids. During this process, One hydroxide ion is required to hydrolyze one ester linkage of a triacylglycerol molecule. Because there are three ester linkages in a triacylglycerol, three equivalents of sodium hydroxide will be needed to completely saponify the triacylglycerol. This explains the reason why saponification of the triacylglycerol iresulted in four different fatty acid salts.
Complete a chair conformation of trans-1-bromo-3-methylcyclohexane by placing the hydrogen, bromine, and methyl groups in the appropriate positions.
Place the bromine on the carbon that is more to the right.
Answer:
Explanation:
The most highly stable cycloalkane is cyclohexane. It does not suffer from an angle or torsional strain, and it has the appropriate stability as chain alkanes. Because of the peculiar conformation it takes, this stability leads to the cyclohexane conformation popularly known as the "chair" conformation.
However, from the information given;
The chair conformation structure of trans-1-bromo-3-methylcyclohexane is carefully drawn and the substituents are appropriately attached in the image below.
Identifying Independent and Dependent Variables Read each of the following short descriptions of an experiment and identify the independent anddependent variables in each. It is likely that you have observed a sealed soda can left out in a hot car expands. Based on the notion that gas escapes a liquid at high temperatures, a student chose to investigate the amount of dissolve oxygen in a local pond over a 12-month period. Sulfur dioxide is a commonly used preservative in wine as it prevents oxidation and bacterial growth. A wine producer would like to explore if pH affects the solubility of SO2 in the wine, and therefore decides to measure the SO2 in the wine solution over a range of pH values. The H2SO4 electrolyte concentration impacts the performance of lead-acid batteries, commonly used as car batteries. A researcher wishes to determine the optimal H2SO4 concentration for the best performance of the battery, as measured by the voltage output. Identify the independent and dependent variable for each scenario in the textfield below.
Saved Biliy Normal X2 X + ELEIE BIT Julie TE
1. Independent variable Dependent variable
2. Independent variable Dependent variable
3. Independent variable Dependent variable
Answer:
a) Independent variable - Temperature
Dependent variable - amount of dissolve oxygen over a 12-month period
b) Independent variable - pH
Dependent variable - solubility of SO2 in the wine
c) Independent variable - H2SO4 concentration
Dependent variable - voltage output.
Explanation:
An independent variable is the one whose value remain constant while a dependent variable is one whose values changes and is dependent on the independent variable
a) Independent variable - Temperature
Dependent variable - amount of dissolve oxygen over a 12-month period
b) Independent variable - pH
Dependent variable - solubility of SO2 in the wine
c) Independent variable - H2SO4 concentration
Dependent variable - voltage output.
Need help please I need to select one element for each following families on the periodic table
Answer:
Semi Metals-Boron, Silicon
Noble Gasses-Helium, Argon
Halogens-Clorine, Iodine
Transition metals-Iron, Tungsten
Alkaline earth metals-Calcium, Magnesium
write the formula
fluoride ion
Answer:
F-
Explanation:
Since Fluorine needs one more electron to reach a full octet, it takes in 1 more electron to become an anion. Therefore, with the extra negative charge from the 1 electron, a Fluoride ion has a charge of -1.
Hope this helped!
Answer:
F_
Explanation:
the symbol or formula
is F_
1.00 liter solution contains 0.31 M acetic acid and 0.40 M sodium acetate. If 0.100 moles of calcium hydroxide are added to this system, indicate whether the following statements are true or false. (Assume that the volume does not change upon the addition of calcium hydroxide.)
_______ A. The number of moles of CH3COOH will decrease.
_______ B. The number of moles of CH3COO- will decrease.
_______ C. The equilibrium concentration of H3O will decrease.
_______ D. The pH will decrease.
_______ E. The ratio of [CH3COOH] / [CH3COO-] will remain the same.
Answer:
The answer is the explanation.
Explanation:
The acetic acid, CH3COOH, reacts with calcium hydroxide, Ca(OH)2, producing acetate ion, CH3COO- and water as follows:
2CH3COOH + Ca(OH)2 → 2CH3COO- + 2H2O + Ca²⁺
That means the moles of acetic acid decrease whereas the moles of acetate ion are increased. The ratio of [CH3COOH] / [CH3COO-] is different.
As a base is added, the concentration of H3O+ decreases increasing the pH.
That means:
TRUE A. The number of moles of CH3COOH will decrease.
FALSE B. The number of moles of CH3COO- will decrease.
TRUE C. The equilibrium concentration of H3O will decrease.
FALSE D. The pH will decrease.
FALSE E. The ratio of [CH3COOH] / [CH3COO-] will remain the same.
B. It shifts the equilibrium toward the right, favoring product.
11. What is meant by the term heat of reaction?
A. the difference in temperature between products and reactants
B. the difference in bond energies between products and reactants
C. the difference in heat energies between products and reactants
What other name is a synonym for this term?
A. entropy change
B. potential change
C. enthalpy change
Answer:
11) the difference in heat energies between products and reactants
12) enthalpy change
Explanation:
The heat of reaction is defined as that energy released or absorbed as chemical substances participate in a chemical reaction. It is a term used to denote the change in energy as reactants change into products.
Another name of heat of reaction is enthalpy of reaction. It is a state function since it depends on the initial and final states of the system.
list some applications of chemistry in your dail life
Chemistry and chemical reactions are not just limited to the laboratories but also the world around you.
Chemistry in Food Production:
Plants produce food for themselves through photosynthesis; which is a complex chemical reaction in itself. The chemical reaction that takes place in photosynthesis is the most common and vital chemical reaction.
6 CO2 + 6 H2O + light → C 6H12O6 + 6 O2
Chemistry in Hygiene:
Right before you consume your food, you make it a point to wash your hands with soap. Isn’t it? The cleaning action of soap is based on its ability to act as an emulsifying agent. Soaps are fatty acids salts of sodium or potassium; produced by a chemical reaction called saponification. Soaps interact with the grease or oil molecule, which, in turn, results in a cleaner surface.
The Chemistry of an Onion:
Ever wondered why you shed tears while chopping an onion? This also happens because of the underlying chemistry concepts. As soon as you slice an onion, sulfenic acid is formed from amino acid sulfoxides. Sulfenic acid is responsible for the volatile gas, propanethiol S-oxide, that stimulates the production of tears in the eyes.
Chemistry in Baking:
Who does not like to eat fluffy freshly baked bread? Baking soda is an efficient leavening agent. The addition of baking soda to food items before cooking leads to the production of carbon dioxide (CO2); which causes the foods to rise. This whole process of rising of baked good is called chemical leavening.
Chemistry in Food Preservatives:
In case you ever read the ingredients on the bottle of ketchup, jams or pickles, you might be surprised to see a never-ending list of chemicals. What are they? These chemicals are called food preservatives; which delay the growth of microorganisms in foods. The chemical food preservatives not only prohibit the growth of bacteria, virus, fungi but also hinder the oxidation of fats, which is responsible for making the foods rancid. The most common chemical food preservatives are sodium benzoate, sorbic acid, potassium sorbate, calcium sorbate, sodium sorbate, propionic acid, and the salts of nitrous acid.
Chemistry in Digestion
The moment you put food in your mouth, a number of different chemical reactions start in your digestive tract. Saliva contains the enzyme amylase, which is responsible for breaking down carbohydrates, the stomach starts producing hydrochloric acid, the liver releases bile and the list of compounds released during digestion goes on. How do they work? All these enzymes undergo chemical reactions so that proper digestion, as well as assimilation of the food, occurs.
The Working of a Sunscreen
Before going out on a sunny day, you make it a point to wear sunscreen. Even the principle, behind the working of a sunscreen, has a chemistry background. The sunscreen uses a combination of organic and inorganic compounds to act as a filter for incoming ultraviolet rays. Sunblocks, on the other hand, scatter away UV light; so that it is unable to penetrate deep into the skin. Sunblocks contain complex chemical compounds like zinc oxide or titanium oxide, which prevent the UV rays to invade deeper into the skin.
Chemistry in Rust Formation
With time, your iron instruments start developing an orange-brown flaky coating called rust. The rusting of iron is a type of oxidation reaction. The atoms in the metal iron undergo oxidation and reduction; causing rusting. The formation of verdigris on copper and the tarnishing of silver are also the other everyday examples of chemical reactions. The chemical equation underlying rusting is:
Fe + O2 + H2O → Fe2O3. XH2O
Hope it helps.
(Ch3ch2)2choh oxidize with k2cr2o7?
pasagot po please!!
science po ito pasagot po matino need ko po!!
Explanation:
Efficiency = (output/input)×100%
70% = output/(800 W)
which means
output = 0.70×(800 W) = 560 W
For alkyl halides used in SN1 and SN2 mechanisms, rank the leaving groups in order of reaction rate. You are currently in a ranking module. Turn off browse mode or quick nav, Tab to move, Space or Enter to pick up, Tab to move items between bins, Arrow Keys to change the order of items, Space or Enter to drop.
Answer:
Iodide> Bromide > chloride > flouride
Explanation:
During a nucleophilic substitution reaction, a nucleophilie replaces another in a molecule.
This process may occur via an ionic mechanism (SN1) or via a concerted mechanism (SN2).
In either case, the ease of departure of the leaving group is determined by the nature of the C-X bond. The stronger the C-X bond, the worse the leaving group will be in nucleophilic substitution. The order of strength of C-X bond is F>Cl>Br>I.
Hence, iodine displays the weakest C-X bond strength and it is thus, a very good leaving group in nucleophillic substitution while fluorine displays a very high C-X bond strength hence it is a bad leaving group in nucleophilic substitution.
Therefore, the ease of the use of halide ions as leaving groups follows the trend; Iodide> Bromide > chloride > flouride
what does PH scale measure
Explanation:
pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.
The literature values listed for the unknowns in this assignment are from either the Merck Index or the CRC Handbook, the two most used reference handbooks. However, the values tend to vary slightly across literature sources and sometimes the temperatures are given as ranges. Give at least one reason for the variations in these reported temperatures.
In general, the boiling points of compounds increase down a group in the periodic table. The melting points and boiling points for the hydrogen compounds of group 6A elements are in the table below.
Melting point (0C) Boiling point (oC)
H2O 0.0 100.0
H2S -82.0 -60.0
H2Se -65.7 -41.2
H2Te -49.0 -2.2
Answer:
See explanation
Explanation:
One of the important trends in the periodic table is electronegativity. Electro negativity decreases down the group and increases across the period. This trend has important consequences on the observed properties of the compounds of elements in a particular group in the periodic table.
As we move down in group 6A, the electro negativity of the elements elements the group decrease and as such, the magnitude of intermolecular hydrogen bonding between the molecules also decrease accordingly. Hydrogen bonds occur between
molecules of a substance when hydrogen is covalently bonded to an electronegative element. Hydrogen bonding is responsible for the high melting and boiling points of small molecules such as water which contain the highly electronegative oxygen atom.
So, as we move down the group there is lesser intermolecular hydrogen bonding between the hydride molecules of group 6A elements resulting in the observed trend in melting and boiling points of the hydrides.
The weaker hydrogen bonds that occurbetween molecules of group 6A hydrides lead to a steady decrease in melting and boiling points of the hydrides of group 6A elements as we move down the group.