Answer:
alkali metal
Explanation:
The alkali metals in period 4 will have the lowest ionization energy of the elements in the period.
Across a period ionization energy increases progressively from left to right due to decreasing atomic radii caused by the increasing nuclear charge which is not compensated for by successive electronic shells.
Ionization energy is the energy needed to remove the most loosely bound electrons of an atom in the gas phase in the ground state. The measure of the readiness of an atom to lose an electron is the ionization energy.Down a group, it decreases.
The periodic table is the arrangement of the elements based on the atomic numbers. The elements of the alkali period have the lowest ionization energy.
What is ionization energy?Ionization energy or the potential is the amount of the potential needed by the molecule or the atom to remove the electron from their shells. The alkali metal elements have the lowest ionization energy.
The ionization potential of the elements increases from the left towards the right of the period due to the decrease in the atomic radii and decreases from top to bottom in a group.
In the period from left to right the atomic radius of the atoms decreases due to the increase in the nuclear charge of the atoms.
Therefore, option B. alkali metal has the lowest ionization energy.
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which of the following is an example of a decomposition reaction
Answer:
Examples of decomposition reactions include the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen.
If the % acetic acid listed on a vinegar bottle is 4%, what is the implied uncertainty of the acetic acid concentration
Answer:
This question appears incomplete
Explanation:
This question appears incomplete because the data provided only makes it possible to calculate the certainty of the acetic acid content per total volume of the vinegar. Thus, the 4% means for every 100 mL of the vinegar, there is 4 mL of acetic acid present. To calculate the volume of acetic acid in any other volume of vinegar, the formula will be
volume of acetic acid = 4/100 × total volume of vinegar
A student with a body temperature of 37℃ holds a piece of ice that has a temperature of -8℃. Which statement best explains what happens?
A. Heat transfers coldness from the ice to the student's hand.
B. Thermal energy transfers heat from the student's hand to the ice.
C. Heat transfers thermal energy from the student's hand to the ice.
D. Thermal energy transfers coldness from the student's hand to the ice.
Answer: C. Heat transfers thermal energy from the student's hand to the ice.
Explanation: It seems confusing; b and c seem to be saying the same thing, but the definition of heat is the transfer of thermal energy from a warmer object to a colder object.
A pure substance made of two two or more elements that are chemically combined is a(n)
Answer:
A pure substance made up of two or more elements that are chemically combined is a compound
Explanation:
An atom has 10 protons and 10 electrons. What happens to the charge if you add 1 more electron
Answer:
it becomes a negstive charge
How many atoms are in 15.6 grams of silicon?
Answer:
3.34 x 1023 atoms
Explanation:
Question 2 (2 points)
Saved
How many grams of water do will you need to prepare 480 g of 8.5% solution of
C6H12O6
Answer:
[tex]m_w=439.2g[/tex]
Explanation:
Hello!
In this case, since the by-mass percent of a solution is a measure of the mass of the solute over the mass of the solution:
[tex]\%m/m=\frac{m_{solute}}{m_{solution}} *100\%[/tex]
As we know the mass of the solution and the by-mass percent, we can compute the mass of glucose in the 480 g of solution:
[tex]m_{solute}=\frac{\%m/m*m_{solution}}{100\%}[/tex]
Thus, by plugging in the data, we obtain:
[tex]m_{solute}=\frac{8.5\%*480g}{100\%}=40.8g[/tex]
Finally, since the solution is made up of glucose and water, we compute the mass of water as follows:
[tex]m_w=m_{sol}-m_{solute}=480g-40.8g\\\\m_w=439.2g[/tex]
Best regards!
Which of the following statements is true about covalent bonds?
a) The shared electrons provide both atoms with an octet.
b) Sometimes electrons are gained to provide an atom with an octet.
OC) Hydrogen will share its one electron to obtain an octet
O d) The shared electrons are attracted by the nuclei of both atoms.
e) both a and d.
Answer:
the answer is D.)
Explanation:
When NaCl is dissolved in water, it separates into Na+ and CI-ions, which are also dissolved in water. How would the phase of the NaCl, the Na+, and the CI-
be written in the reaction equation?
A. (g)
B. (1)
C. (aq)
D.(s)
Answer:
C aq
Explanation:
Means desolves in water
When NaCl is dissolved in water, it separates into its constituent ions Na+ and Cl- ions. The phase of the ions are written as (aq) and that of NaCl is written as (s) .
What is NaCl ?Sodium chloride is an ionic compound formed by the transfer of electrons from the metal sodium to the nonmetal chlorine. It is used as the common table salt.
Na contains one valence electron and Cl contains 7 valence electrons. Hence, Na can donate that electron to Cl to achieve octet in both. When Na loss an electron it forms Na+ and Cl gains the electron to form Cl-. These two ions are then attracts to form the NaCl.
When NaCl is dissolved in water the bond between these two ions weaken and the ions gets released into the solution. The ions in the solution is indicated with the phase aqueous (aq) and the undissolved NaCl is in solid (s) state.
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2 C2H2 + 5 O2
2 H2O + 4 CO2
what reaction type
Answer:
Combustion reaction
General Formulas and Concepts:
Chemistry
Synthesis Reactions: A + B → ABDecomposition Reactions: AB → A + BSingle-Replacement Reactions: A + BC → AB + CDouble-Replacement Reactions: AB + CD → AD + BCExplanation:
Step 1: Define
2C₂H₂ + 5O₂ → 2H₂O + 4CO₂
Step 2: Identify
Any organic molecule reacting with oxygen to produce water and carbon dioxide is a combustion reaction.
We also see from the RxN that is is a double replacement reaction.
Answer:
Answer: 0.4 g
Explanation:
1) Balanced chemical equation:
2) 2C2H2 + 5 O2 → 4CO2 + 2 H2O
3) mole ratios:
2 mol C2h2 : 5 mol O2
4) Convert 0.13 g C2H2 into number of moles
n = mass in grams / molar mass
molar mass C2H2 = 2 *12g/mol + 2*1 g/mol = 26 g/mol
n = 0.13 g / 26 g/mol = 0.005 mol
5) Set the proportion with the unknown
5 mol O2 x
----------------- = ---------------
2 mol C2H2 0.005 mol C2H2
x = 0.005 mol C2H2 * 5 mol O2 / 2 mol C2H2 = 0.0125 mol O2
6) Convert 0.0125 mol O2 to grams
mass = number of moles * molar mass
molar mass of O2 = 32 g/mol
mass = 0.0125 mol * 32 g/mol = 0.4 g
Answer: 0.4 g
Explanation:
A chemist dissolves 249.mg of pure perchloric acid in enough water to make up 380.mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.
Answer:
pH = 2.18
Explanation:
Perchloric acid (HClO₄) is a strong acid. This means that in an aqueous solution it completely dissociates into H⁺ and ClO₄⁻ species.
First we convert 249 mg HClO₄ into moles, using its molecular weight:
249 mg HClO₄ ÷ 100.46 mg/mmol = 2.49 mmol HClO₄Because it is a strong acid, 2.49 mmol HClO₄ = 2.49 mmol H⁺
We calculate the molar concentration of H⁺:
2.49 mmol H⁺ / 380 mL = 6.52x10⁻³ MFinally we calculate the pH of the solution:
pH = -log[H⁺] = -log(6.52x10⁻³)pH = 2.18what type of change occurs when rust on a nail a. chemical change b. physical change
Answer:
Chemical change
Explanation:
The rusting of iron/a nail is a chemical change
Iron (Fe) and Oxygen (O) combine to create the compound Iron Oxide (Fe2O3), which is rust.
The polar bear runs at a speed of 8.3 m/sec, how long will it take it to run 200
meters?
Answer:speed of 6.5 meters per second, what is the distance she covers in that time? ... backstrokes at an average speed of 8 meters per second, how long will it take ... 200m smis. 255. 7. Lauren's SUV was detected exceeding the posted speed limit ... Suppose the polar bear was running on land instead of swimming. ... V = 8.3mls.
Explanation:
[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]
Actually Welcome to the Concept of the Kinematics.
Since, we know that,
Time = Distance / Speed
so here, Speed = 8.3 m/s and Distance= 200m
so we get as, T = 200/8.3 => 24.09 seconds.
Hence, time taken will be => 24.09 seconds.
among the intermolecular forces,which forces are typically the weakest
Answer:
The London dispersion force is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles.
What is the wavelength, in nanometers, of light with a frequency of 1.90x10^15 Hz?
Answer:
1.58×10² nm
Explanation:
Given data:
Frequency of light = 1.90 ×10¹⁵ Hz
wavelength of light = ?
Solution:
Speed of light = wavelength × Frequency
Speed of light = 3×10⁸ m/s
3×10⁸ m/s = λ × 1.90 ×10¹⁵ Hz
Hz = s⁻¹
λ = 3×10⁸ m/s / 1.90 ×10¹⁵s⁻¹
λ = 1.58×10⁻⁷ m
meter to nm:
1.58×10⁻⁷ m ×10⁹ nm/ 1m
1.58×10² nm
Calculate the standard cell potential, ∘cell, for the equation Co(s)+F2(g)⟶Co2+(aq)+2F−(aq) Use the table of standard reduction potentials. ∘cell=
Answer:
3.15 V
Explanation:
Step 1: Write the balanced cell reaction
Co(s) + F₂(g) ⟶ Co²⁺(aq) + 2 F⁻(aq)
Step 2: Identify both half-reactions:
Cathode (reduction): F₂(g) + 2 e⁻ ⟶ 2 F⁻(aq) E°red = 2.87 V
Anode (oxidation): Co(s) ⟶ Co²⁺(aq) + 2 e⁻ E°red = -0.28 V
Step 2: Calculate the standard cell potential
We will use the following expression.
E°cell = E°red,cathode - E°red,anode
E°cell = 2.87 V - (-0.28 V) = 3.15 V
Given E°cell > 0, the reaction is spontaneous.
Taking into account the definition of standard cell potential, E°cell has a value of 3.15 V.
The balanced cell reaction is:
Co(s) + F₂(g) ⟶ Co²⁺(aq) + 2 F⁻(aq)
First of all, it must be taken into account that oxidation is a reaction where an atom, ion or molecule loses electrons while reduction corresponds to the gain of electrons from an atom, ion or molecule.
Both oxidation and reduction depend on the change in the oxidation state of the atom, that is, on the difference in the charge of the atom in a reaction.
The oxidation and reduction reactions always occur simultaneously for what are generally known as oxidation-reduction reactions or redox reactions.
So, the anode corresponds to the negative electrode which normally oxidizes in the electrolytic chemical reaction while the cathode corresponds to the positive electrode which normally reduces its oxidation state when it receives electrons.
Si, in this case, the both half-reactions will be:
Cathode (reduction): F₂(g) + 2 e⁻ ⟶ 2 F⁻(aq) E°red = 2.87 V Anode (oxidation): Co(s) ⟶ Co²⁺(aq) + 2 e⁻ E°red = -0.28 V
The potential of an Ecel cell is a measure of the difference in electronic energy between the two electrodes. The electronic energy of each electrode is related to the force with which the reaction occurs at the electrode-solution interface. The unit in which it is measured is the volt.
In electrochemistry, because a cell reaction is made up of two half-cell reactions, each of which has a characteristic electrode potential, the potentials measure the driving force of the two half-reactions.
The cell potential is obtained by subtracting the potentials of both half cells as shown below:
E°cell= Ecatode - Eanode
So, in this case, the Ecell is calculated as:
E°cell = 2.87 V - (-0.28 V) = 3.15 V
In summary, E°cell has a value of 3.15 V.
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one
two
O three
o eight
none
Answer:
Two.
Explanation:
Hello!
In this case, considering the attached picture wherein you can see the presence of the parent chain as aniline, we can see radicals at the nitrogen, named by N-ethyl and N-methyl which are the present alkyl substituents. In such a way, the benzene ring is not considered an alkyl radical because it belongs to the parent chain on aniline and therefore, N-ethyl-N-methylaniline has two alkyl substituents.
Best regards!
There are two alkyl substituents attached to the nitrogen; one ethyl and one methyl group
Aniline consists of a benzene ring to which an -NH2 moiety is attached. Usually, it is possible for the any of the two hydrogen atoms in the -NH2 moiety to become substituted leading to N-alkylated product.
In the compound N-ethyl-N-methylaniline, there are two alkyl substituents attached to the nitrogen; one ethyl and one methyl group as shown in the image attached to this answer.
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A party balloon filled with helium deflates to 2/3 of its original volume in 8.0 hours. How long will it take an identical balloon filled with the same number of moles of air (ℳ = 28.2 g/mol) to deflate to 1/2 of its original volume?
Answer:
The easy way to do this is to assume the number of moles. Make it a number easily divided by both 2 and 3, so say 6. Now you can have numbers to plug in to Graham's Law to find the second rate, then use the second rate to find the time. Does that make sense?
A.) What is the mass in g of 5 mols of Mg?
B.) If you are given 7.4 *10^23 atoms of Cu, how many mols of Cu do you have?
Answer:
Mass of Mg = 120 g
1.23 moles of Cu
Explanation:
A)
Given data:
Number of moles of Mg = 5 mol
Mass of Mg = ?
Solution:
Number of moles = mass/molar mass
Molar mass of magnesium is 24 g/mol.
5 mol = mass/ 24 g/mol
Mass = 5 mol × 24 g/mol
Mass = 120 g
B) Given data:
Number of atoms of Cu = 7.4 ×10²³ atom
Number of moles of Cu = ?
Solution:
Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
7.4 ×10²³ atom × 1 mol / 6.022 × 10²³ atom
1.23 moles of Cu
To prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol), how many grams of sodium chloride is required?
11.12 grams of sodium chloride is required to prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol).
HOW TO CALCULATE MASS:
The mass of a substance can be calculated by multiplying the number of moles of the substance by its molar mass. However, the number of moles of sodium chloride must first be calculated by multiplying the molarity by its volume. Molarity = no. of moles ÷ volume 0.500M = n ÷ 0.380Ln = 0.5 × 0.380n = 0.19molmass of NaCl = 58.5g/mol × 0.19molMass of NaCl = 11.12gTherefore, 11.12 grams of sodium chloride is required to prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol).Learn more about how to calculate mass at: https://brainly.com/question/14948089?referrer=searchResults
A substance that functions to prevent rapid, drastic changes in the pH of a body fluid by changing strong acids and bases into weak acids and bases is called a(n):
A. Buffer
B. Salt
C. Enzymes
D. Coenzyme
2. Calculate the new molanty of a solution formed when 20 ml of water is added to 100 ml of
0.2M NaOH
Answer:
New molarity = M₂ = 0.167 M
Explanation:
Given data:
New molarity = M₂ = ?
Final volume = V₂ = 100mL + 20 mL = 120 mL
Initial volume =M₁ = 100 mL
Initial molarity =V₁ = 0.2 M
Solution:
M₁V₁ = M₂V₂
0.2 M × 100 mL = M₂ × 100 mL
M₂ = 0.2 M × 100 mL/120 mL
M₂ = 20 M.mL/120 mL
M₂ = 0.167 M
A negative ion is known as a(n) *
ionic radius.
valence electron.
cation.
anion.
Answer:
Positively charged ions are called cations; negatively charged ions, anions
Which unit is used to express a amount of thermal energy
Answer:
Joule
Explanation:
Answer:
The calorie
Explanation: as the amount of thermal energy necessary to raise the temperature of one gram
Why is K lighter than Na
Answer:
Basically, in the case of sodium and potassium the increase in shell size outweighs the pull of the core on the outer shell electron and so potassium is less dense than sodium. When we more from Na to K, effect of increase in volume is more pronounced as compared to effect of increase in atomic mass.
A gas-forming reaction produces 1.95 m3 of gas against a constant pressure of 196.0 kPa. Calculate the work done by the gas in joules.
Answer:
Work done W = -382,206 J (Approx)
Explanation:
We know that;
1 atm = 101.32 kPa
1 L-atm = 101.325 J
1 m³ = 1,000 L
Computation:
Work done W = -P∆V
Pressure = 196 kPa × (1 / 101.32 kPa)
Pressure = 1.9344 atm
∆V = 1.95 × (1000 L) = 1,950 L
So,
W = -(1.9344 atm) × (1,950 L)
W = -3772.0 L-atm
Work done W = -3772.0 L-atm × (101.325 J / 1 L.atm)
Work done W = -382,206 J (Approx)
The work done by the gas in Joules is equal to 3,763.5 Joules.
Given the following data:
Pressure = 196.0 kPa. Volume = 1.95 [tex]m^3[/tex]Conversion:
1 atm = 101.325
X atm = 196.0 kPa
X = [tex]\frac{196.0}{101.325} = 1.93\; atm[/tex]
Conversion:
1 [tex]m^3[/tex] = 1000 Liter
1.95 [tex]m^3[/tex] = 1950 Liter
To calculate the work done by the gas in Joules:
Mathematically, the work energy by a system is given by the formula:
[tex]Work = P \delta V[/tex]
Where:
P is the pressure. V is the volume.
Substituting the parameters into the formula, we have
[tex]Work\;energy = 1.93 \times 1950[/tex]
Work energy = 3,763.5 Joules.
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Each pure substance has characteristic physical and chemical properties that can be used to identify it.
Compare and contrast physical properties and chemical properties of a substance. Give and example for each:
Give two everyday examples of the thermal energy of a substance being decreased
Answer:
An example of the thermal energy of a substance being decreased is with our food. With the thermal energy of food being decreased it is easier for foods to be eaten comfortably without any damage to the tongue or alimentary canal.
Another good example is in the handling of hot objects in the home. Thermal energy decrease in objects such as iron, pots etc helps to prevent serious burns and injuries.
Answer:
Water turning into ice
juice frozen to make popsicles
Explanation:
When something goes from liquid to a solid, that is a process called freezing. When a object loses thermal energy the particles move slower forming a solid.
How many moles of mercury are 4.000 x 1022 atoms of mercury?
Answer:
0.06642 moles of mercury
Explanation:
Step 1: Given data
Moles of mercury: 4.000 × 10²² atoms
Step 2: Calculate the number of moles of mercury that correspond to 4.000 × 10²² atoms of mercury
To convert atoms to moles, we need to consider the Avogadro's number: there are 6.022 × 10²³ atoms of mercury per mole of mercury.
4.000 × 10²² atoms × (1 mol/6.022 × 10²³ atoms) = 0.06642 mol
What is the molarity of 9.0 moles of NaCl dissolved in 15.0 liters if solution?