Answer:
[tex]6.43x19^8mg[/tex]
Explanation:
Hello,
In this case, this unit conversion is performed by knowing that 1 kg of mass contains 1000 g and 1 g contains 1000 mg, therefore, the result is:
[tex]643kg*\frac{1000g}{1kg} *\frac{1000mg}{1g}\\ \\=6.43x10^8mg[/tex]
Regards.
The following reaction is second order in [A] and the rate constant is 0.025 M-1s-1: The concentration of A was 0.65 M at 33 s. The initial concentration of A was ________ M.
Select one:
a. 0.24
b. 1.2 � 10-2
c. 0.27
d. 2.4
e. 1.4
Answer:
e. 1.4.
Explanation:
Hello,
In this case, for a second-order reaction, the integrated rate law is:
[tex]\frac{1}{[A]} =kt+\frac{1}{[A]_0}[/tex]
In such a way, for the given data, we compute the initial concentration as shown below in molar units (M):
[tex]\frac{1}{[A]_0} =\frac{1}{[A]}-kt=\frac{1}{0.65M} -\frac{0.025}{M*s}*33s \\\\\frac{1}{[A]_0} =\frac{0.713}{M}[/tex]
[tex][A]_0=\frac{1M}{0.713} =1.4M[/tex]
Therefore, answer is e. 1.4 M.
Regards.
The initial concentration of the reaction is 1.4 M.
Using the formula;
1/[A] = kt + 1/[A]o
Where;
[A] = concentration at time t = 0.65 M
t = time = 33 s
k = rate constant = 0.025 M-1s-1
[A]o = initial concentration = 0.025 M-1s-1
Hence;
1/ 0.65 = (0.025 × 33) + 1/[A]o
1/[A]o = (0.65)^-1 - (0.025 × 33)
1/[A]o = 1.54 - 0.83
[A]o = 1.4 M
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Please use your periodic table of elements to assist you. How many protons does Flourine have? Question 3 options: 8 18 9 10
Answer:
9 protons
Explanation:
An element's atomic number is equal to the amount of protons in the nucleus - otherwise, the element's chemical identity would be different and it would be a completely different element.
Referencing any periodic table, we notice that fluorine has the atomic number of 9.
Because the atomic number is the same as the number of protons in the nucleus, fluorine has 9 protons.
What is the molarity of a solution in
which 6.9mol of potassium chloride
(KCI) is dissolved in water to a final
volume of 1.8L?
Answer:
3.83 mol/ L
Explanation:
Molarity is the amount of moles of a substance in a liter of solution.
1.8L ----- 6.9 mol of KCl
1L ----- 6.9 ÷1.8= 3.83 moles of KCl (3 s.f.)
Thus the molarity is 3.83 mol/L.
Answer: 3.8
Explanation:
Original answer is 3.83 but it needs significant figures so you need to round it to 2 significant figures
For each of the reactions, calculate the mass (in grams) of the product formed when 15.93 g of the underlined reactant completely reacts. Assume that there is more than enough of the other reactant.
1) 2K(s)+Cl2(g)/15.93G→2KCl(s)
2) 2K(s)+Br2(l)/15.93→2KBr(s)
3) 4Cr(s)+3O2(g)/15.93→2Cr2O3(s)
4) 2Sr(s)/15.93+O2(g)→2SrO(s)
Answer:
1. 33.43 g of KCl
2. 23.70 g of KBr
3. 50.45 g of Cr₂O₃
4. 18.82 g of SrO
Explanation:
Molar mass of the elements and compounds in each of the reactions:
K = 39.0 g, Cl = 35.5 g, KCl = 74.5 g, Br = 80.0 g, KBr = 119.0 g, Cr = 52.0 g, O = 16.0 g, Cr₂O₃ = 152.0 g, Sr = 88.0 g, SrO = 104.0 g
1) 2K(s)+Cl2(g)/15.93G→2KCl(s)
From the mole ratio of the reaction above, 2 moles of K reacts with 1 mole of Cl₂ to give 2 moles of KCl
78.0 g (2 * 39.0 g) of K reacts with 71.0 g (2*35.5) of Cl₂ to produce 149.0 g(2*74.5) of KCl, therefore, Cl₂ is the limiting reactant.
15.93 g of Cl₂ will react to produce (149/71) * 15.93 of KCl = 33.43 g of KCl
2) 2K(s)+Br2(l)/15.93→2KBr(s)
From the mole ratio of the reaction, 2 moles of K reacts with 1 mole of Br₂ to give 2 moles of KBr
78.0 g (2 * 39.0 g) of K reacts with 160.0 g (2*80) of Br₂ to produce 238.0 g(2*119.0) of KBr, therefore, K is the limiting reactant which though is in excess.
15.93 g of Br₂ will react to produce (238/160) * 15.93 of KBr = 23.70 g of KBr
3) 4Cr(s)+3O2(g)/15.93→2Cr2O3(s)
From the mole ratio of the reaction, 4 moles of Cr reacts with 3 moles of O₂ to give 2 moles of Cr₂O₃
208.0 g (4 * 52.0 g) of Cr reacts with 96.0 g (3*2*16) of O₂ to produce 304.0 g (2*152.0) of Cr₂O₃, therefore, O₂ is the limiting reactant.
15.93 g of O₂ will react to produce (304/96) * 15.93 of Cr₂O₃ = 50.45 g of Cr₂O₃
4) 2Sr(s)/15.93+O2(g)→2SrO(s)
From the mole ratio of the reaction, 2 moles of Sr reacts with 1 mole of O₂ to give 2 moles of SrO
176.0 g (2* 88.0 g) of Sr reacts with 32.0 g (2*16) of O₂ to produce 208.0 g (2*104.0) of SrO, therefore, O₂ is the limiting reactant which though is in excess.
15.93 g of Sr will react to produce (208/176) * 15.93 of SrO = 18.82 g of SrO
What would be the major product obtained from hydroboration–oxidation of the following alkenes?
a. 2-methyl-2-butene
b. 1-methylcyclohexene
Answer:
a. 3-methylbutan-2-ol
b. 2-methylcyclohexan-1-ol
Explanation:
For this reaction, we must remember that the hydroboration is an "anti-Markovnikov" reaction. This means that the "OH" will be added at the least substituted carbon of the double bond.
In the case of 2-methyl-2-butene, the double bond is between carbons 2 and 3. Carbon 2 has two bonds with two methyls and carbon 3 is attached to 1 carbon. Therefore the "OH" will be added to carbon three producing 3-methylbutan-2-ol.
For 1-methylcyclohexene, the double bond is between carbons 1 and 2. Carbon 1 is attached to two carbons (carbons 6 and 7) and carbon 2 is attached to one carbon (carbon 3). Therefore the "OH" will be added to carbon 2 producing 2-methylcyclohexan-1-ol.
See figure 1
I hope it helps!
How many moles of urea (60. g/mol) must be dissolved in 66.6g of water to give a 2.4 m solution?
a. 1.4 × 102 mol
b. 2.4 mol
c. 0.0024 mol
d. 0.15 mol
e. 9.0 × 102 mol
Answer:
d. 0.15 mol
Explanation:
Step 1: Given data
Mass of water (solvent): 66.6 gMolality (m): 2.4 mMoles of urea (solute): ?Step 2: Convert the mass of the solvent to kilograms
We will use the relationship 1 kg = 1,000 g.
66.6 g × (1 kg/1,000 g) = 0.0666 kg
Step 3: Calculate the moles of solute
The molality is equal to the moles of solute divided by the kilograms of solvent.
m = moles of solute / kilograms of solvent
moles of solute = m × kilograms of solvent
moles of solute = 2.4 mol/kg × 0.0666 kg
moles of solute = 0.15 mol
The radioactive atom R 88 210 a is an alpha emitter. What nucleus does it produce?
Answer:
X 86 206
Explanation:
Radioactive atoms are nuclei that can under go disintegration to emit either an alpha particle, beta particle or gamma radiation. The process could be spontaneous or stimulated.
When a radioactive atom R 88 210 emits alpha particle, it would produce an element with atomic number 86 and mass number 206 i.e X 86 206. An alpha particle is usually a helium nucleus.
[tex]R^{210}[/tex] ⇒ [tex]x^{206}[/tex] + [tex]He^{4}[/tex] + energy
choose the best answer. The 6.0 M HCl solution must be added to the crucible in the fume hood because
a) the wet hydrogen gas released can cause explosion.
b) the HCl used is very concentrated.
c) it is aafer to do the experiment in the fume hood rather on the bench.
d) the HCl can react quickly with the zinc solid in the fume hood.
Answer:
The answer is A
Explanation:
When nH2/nO2 =3/4 => it can cause explosion
An endothermic reaction is one that:
A. produces light
B. produces gas
C. involves no temperature change
D. absorbs heat
cines exam
Answer:
D. absorbs heat
Explanation:
Examples of endothermic reactions ---
1.Melting ice cubes.
2.Melting solid salts.
3.Evaporating liquid water.
surface tension of solid,liquid and gas
Explanation:
Surface tension is the tendency of liquid surfaces to shrink into the minimum surface area possible. Surface tension allows insects, usually denser than water, to float and slide on a water surface.Tells how many of each atom there are in a formula
Answer:
[tex]\large \boxed{\mathrm{subscripts}}[/tex]
Explanation:
Subscripts are numbers written after elements, subscripts indicate how many of each atom there are in a compound.
The atoms of each element in an compund is written in the subscript. The number of atoms present in any compound whether made up of only same element or different element is termed as Atomicity.
☃️ For Example:Given compound = [tex]\boxed{\sf{H_2O}}[/tex]
Here, there are two atoms of hydrogen and one atom of oxygen, So ratio of the atoms of elements in Water molecule = 2 : 1
━━━━━━━━━━━━━━━━━━━━
Calculate the mass of MgCO3 (84.31 g/mol) precipitated by mixing 10.0 mL of a 0.300 M Na2CO3 solution with 6.00 mL of 0.0400 M Mg(NO3)2 solution.
Answer:
[tex]m_{MgCO_3}=0.0202molMgCO_3[/tex]
Explanation:
Hello,
In this case, for this purpose we first have to write the undergoing chemical reaction:
[tex]Na_2CO_3+Mg(NO_3)_2\rightarrow MgCO_3+2NaNO_3[/tex]
Thus, since the mole ratio between the reactants is 1:1, we next identify the limiting reactant by computing the available moles of sodium carbonate and those moles of the same reactant consumed by the magnesium nitrate considering the given solutions:
[tex]n_{Na_2CO_3}=0.010L*0.300\frac{molNa_2CO_3}{1L}=0.003molNa_2CO_3 \\\\n_{Na_2CO_3}^{consumed}=0.006L*0.0400\frac{molMg(NO_3)_2}{1L}*\frac{1molNa_2CO_3}{1molMg(NO_3)_2} =0.00024molNa_2CO_3[/tex]
In such a way, since less moles are consumed, we can say that the sodium carbonate is excess whereas the magnesium nitrate is the limiting one, therefore, the yielded mass of magnesium carbonate turns out:
[tex]m_{MgCO_3}=0.00024molMg(NO_3)_2*\frac{1molMgCO_3}{1molMg(NO_3)_2}*\frac{84.31gMgCO_3}{1molMgCO_3} \\\\m_{MgCO_3}=0.0202molMgCO_3[/tex]
Regards.
Four research teams measured the length of a rare whale, and what each team wrote in its team notebook is shown in the table below.
Suppose a later and more reliable measurement gives 45.0 m for the length of the same whale. Decide which of the earlier measurements was the most
accurate, and which was the most precise.
team
what was written
in the notebook
most accurate
measurement
most precise
measurement
?
A
"55.m"
B
*50.0m +0.5m
с
*44.0m + 6.0%
D
o
"between 30 m and 40 m
Answer:
Explanation:
Precision relates to instruments of measurement or scale . A scale measuring upto cm is less precise than an instrument measuring upto mm .
Here the first measurement appears to have been taken with an instrument measuring up to metre and the second measurement appears to have been taken with an instrument measuring up to decimeter . So second measurement is most precise .
Third measurement is closest to the actual measurement that is 45.0 m , so it is most accurate measurement .
9.
The main difference between the salt in the Dead
Sea and salt in the school lab is that
A salt in the Dead Sea is saltier.
B salt in the Dead Sea is iodized while that
of the lab is uniodized.
C salt in the Dead Sea is sodium chloride while
that of the lab has its hydrogen replaced.
D salt in the Dead Sea is sodium chloride
while salt in the lab is either soluble or
insoluble in water.
Answer:
salt in the Dead Sea is sodium chloride
while salt in the lab is either soluble or
insoluble in water.
Explanation:
The term 'salt' in the school laboratory does not always refer to sodium chloride. It is a generic term used for many substances especially those substances formed by neutralization reaction.
There are many salts that are used in the laboratory. Some of these salts are soluble in water while some are not soluble in water.
Salt in the dead sea always refers to sodium chloride, hence, salt in the dead sea is different from salt in the school laboratory.
Suppose you wanted to study the relationship between high
school graduation rate and crime. What might your hypothesis be?
What would be the independent variable in your study? The
dependent variable? What existing data could you examine to
support your hypothesis?
Answer:
Hypothesis: High school graduation rate does not have an effect on the rate of crime in the society
Independent variable: Rate of high school graduation
Dependent variable: crime
Existing data: Crime data/reports (for the duration of interest) from different (randomized) police stations and the High school graduation rate data/information (for the same duration of interest) from the schools in the same jurisdictions as the police stations.
Explanation:
1) Before conducting an experiment, a hypothesis has to be put forward. This hypothesis is then proven or unproven by the outcome of the experiment. One of the best ways of proposing a hypothesis is the use of null hypothesis, which suggests that there is no significant difference or "connection" between two variables. Here, the null hypothesis can be "High school graduation rate does not have an effect on the rate of crime in the society"
2) An independent variable is a variable whose variation is not determined or thought to be determined by the change(s) in the other variable. Here, high school graduation rate is not determined or thought to be determined by the other variable.
3) A dependent variable is a variable whose variation is predicted to be as a result of the change(s) in the other variable. Here, the rate of crime is predicted to be as a result of the high school graduation rate
4) Existing/available data that can be used to examine the hypothesis proposed earlier can be obtained from the crime data/reports (for the duration of interest) from different (randomized) police stations and the High school graduation rate data/information (for the same duration of interest) from the schools in the same jurisdictions as the police stations.
The following reaction proceeds at a rate such that 3 mole of A is consumed per minute. Given this, how many moles of C are produced per minute? 2A+2B→4C
Answer:
6 mol/min
Explanation:
2A+2B→4C
The relationship between the reactants and products of this equation is given by;
1/2 -d[A]/dt = 1/2 -d[B]/dt = 1/4 d[C]/dt
Our focus is on A and C
From the question;
d[A]/dt = 3mol/min
We have;
1/2 (3) = 1/4 d[C]/dt
d[C]/dt = 4/2 * 3 = 6 mol/min
Choose the best answer below. If an equal number of moles of lactic acid, HC3H5O3, and potassium hydroxide, KOH, are added to water, is the resulting solution acidic, basic, or neutral? The Ka of lactic acid is 1.4 x10-5.
Answer:
Solution is basic.
Explanation:
When you add the same moles to a weak acid and strong base, you produce a neutralization reaction and a salt. For this case:
CH₃CHOHCOOH + KOH → KCH₃CHOHCOO + H₂O
If we work in a titration, this is the equivalence point where:
moles of base = moles of acid
For this reaction we are only having lactates ions on solution. All the moles from the lactic acid and the hydroxide will be neutralized to make water. As both numbers are the same, the number is the moles of the formed lactate.
If we think the equilibrium equation for lactate, we have:
CH₃CHOHCOO⁻ + H₂O ⇄ CH₃CHOHCOOH + OH⁻
In conclussion, the solution is basic, because we give OH⁻ to medium.
Notice, that in a titratrion of a weak acid and a strong base, the pH at the equivalence point is always basic.
1 how many moles of sodium bicarbonate are needed to neutralize 0.9ml of sulphuric acid at stp
Answer:
8.0356 * 10^-5 moles of NaHCO3
Explanation:
Sulphuric acid = H2SO4
Sodium bicarbonate = NaHCO3
The reaction between both compounds is given by;
2NaHCO3(aq) + H2SO4(aq) → Na2SO4(aq) + 2CO2(g) + 2H2O(l)
In the reactin above;
2 mol of NaHCO3 neutralizes 1 mol of H2SO4
At stp, 1 mol occupies 22.4 L;
1 mol = 22.4 L = 22400 mL
x mol = 0.9 mL
x = 0.9 / 22400 = 4.0178 * 10^-5 moles of H2SO4
Since 2 mol = 1 mol from the equation;
x mol = 4.0178 * 10^-5
x mol = 2 * 4.0178 * 10^-5
x = 8.0356 * 10^-5 moles of NaHCO3
Use the Debye-Huckel Equation to calculate the activity coefficient of Ce4+ at μ = 0.070 M.
english please so i can help
What is the rate constant of a first-order reaction when 20.0% of a reactant remains after 73.5 s?
Answer:
Half-lives of first order reactions
Explanation:
Notice the the half-life is independent of initial concentration. This is not the case with other reaction orders. The half-life of a first-order reaction was found to be 10 min at a certain temperature. hope this helps you :)
0.0453 sec⁻¹ the rate constant of a first-order reaction when 20.0% of a reactant remains after 73.5 s.
What is rate constant?The constant is indeed a proportional factor in chemical kinetics' rate equation that connects reactant molar concentration to reaction rate. It is additionally known as the pre - exponential factor or reaction rate factor and is represented by the symbol k in an equation.
The constant, k, is indeed a constant of proportionality that illustrates the connection between reactant molar concentration and reaction rate. Using the molar quantities of the reagents and the sequence of reaction, the constant may be determined experimentally. It may also be computed using the Following equations.
t1/2 = 0.693/k
Fraction remaining = 0.5n
n = number of half lives
0.20 = 0.5n
log 0.20 = n log 0.5
n = 2.32
2.32 half lives = 35.5 sec
1 half life = 15.3 sec
15.3 sec = 0.693/k
k = 0.0453 sec-1
Therefore, 0.0453 sec⁻¹ the rate constant of a first-order reaction when 20.0% of a reactant remains after 73.5 s.
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422000 scientific notation form:
What information about a chemical solution can be inferred from knowing its pH value?
Answer:
See the answer below
Explanation:
The information than can be inferred from knowing the pH value of a chemical solution is the hydrogen or hydroxyl ion concentration of the solution.
The pH of a solution is the degree of acidity or alkalinity of the solution. Mathematically, the pH of a solution is expressed as:
pH = [tex]-log_{10}[H^+][/tex] where [tex][H^+][/tex] = hydrogen ion concentration.
Also,
pH = 14 - pOH, where pOH = [tex]-log_{10}[OH^-][/tex]
The more the [tex][H^+][/tex] of a solution, the lower the pH, and the more the [tex][OH^-][/tex] of a solution the higher the pH. The pH value ranges from 0 - 14 with 7 being a neutral pH.
Answer:
Explanation:
The hydrogen or hydroxyl ion concentration of the solution could be inferred from knowing its pH value.
1. Which of the following is a physical property of hydrochloric acid?
Fizzes when it is dropped on limestone
b. Turns potassium yellow and chromate orange
is a good conductor of electricity
d. Causes corrosion of magnesium metal
Answer:
c: is a good conductor of electricity
Explanation:
One of the physical properties of hydrochloric acid is that it is a good conductor of electricity in an aqueous state.
The dissolution of hydrochloric acid in water causes a complete dissociation into [tex]H^+[/tex] and [tex]Cl^-[/tex]. The free-floating ions that result from the dissolution enable hydrochloric acid to be able to conduct electricity.
In aqueous solution, the attraction of the positive dipole of the hydrochloric acid to the negative dipole of water and that of the positive dipole of water to the negative dipole of the hydrochloric acid creates a dipole-dipole interaction that allows complete dissociation of the hydrochloric acid. Thus, electrolyte results.
Correct option: c
In this simulation what do you think the bread and cheese separately represent, the atom or the molecule?
Answer:
the atom
Explanation:
The bread and cheese separately represent the atom because both bread and cheese are different from one another and we cannot assume it as a molecule because molecules formed when the group of atoms combine together by making bonds with each other and we know that bread and cheese did not make bonds with each other, they only attached, so we called them atoms not molecule.
With all the complexity in the world or the universe , there are ____ . Kind of like leggos
3. Calculate the amount of C2H5OH in moles present in 5.0 g of ethanol. Calculate the number of C atoms present in the same amount of glucose. g
Answer:
- [tex]n_{etOH}=0.11mol\ et OH[/tex]
- [tex]atoms_C=1.0x10^{23} atoms\ C[/tex]
Explanation:
Hello,
In this case, since ethanol has a molar mass of 46 g/mol, the moles in 5.0 g are:
[tex]n_{etOH}=5.0g\ etOH*\frac{1mol\ etOH}{46 g\ etOH} =0.11mol\ et OH[/tex]
Moreover, since the formula of glucose is C₆H₁₂O₆, its molar mass is 180 g/mol and six moles of carbon are in one mole of glucose (based on carbon's subscript), the atoms are computed by using the 6:1 mole ratio and the Avogadro's number as shown below:
[tex]atoms_C=5.0gC_6H_{12}O_6*\frac{1molC_6H_{12}O_6}{180gC_6H_{12}O_6}*\frac{6molC}{1molC_6H_{12}O_6} *\frac{6.022x10^{23}atoms\ C}{1molC} \\\\atoms_C=1.0x10^{23} atoms\ C[/tex]
Regards.
What nuclide, when bombarded by an α particle, will generate carbon-12 and a neutron?
Answer:
Be
Explanation:
[tex]^94Be + ^42He \rightarrow ^{12}6C + ^10x[/tex]
Therefore, the element symbols is Be, which when bombarded by an α particle, will generate carbon-12 and a neutron.
7. A pair of shared valence electrons is referred to as a(n): hydrophobic effect. van der Waals interaction. ionic bond. hydrogen bond. covalent bond.
Answer:
I believe the answer is a covalent bond
A neutralization of a strong acid by a strong base give out 4590 J of heat energy. Determine the enthalpy change (in kJ) for the reaction. Give your answer to three significant figures.
Answer:
A neutralization of a strong acid by a strong base gave out 5590 J of heat energy.
Determine the enthalpy change (in kJ) for the reaction.
Explanation:
A strong acid being neutralized by a strong base releases 5590 J of heat energy.
What is neutralization?A chemical reaction in which an acid and a base interact quantitatively is known as neutralization or neutralisation. By neutralizing a reaction in water, surplus hydrogen or hydroxide ions are removed from the solution.
Neutralization is a sort of chemical reaction in which an acid and a base combine to produce salt and water. For instance: Reaction of sodium hydroxide and hydrochloric acid (HCl) Sodium hydroxide reacts with hydrochloric acid to form their salt sodium chloride (NaCl) and water.
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Specify whether each compound is soluble in hexane.Classify the appropriate items to their respective category.
a. hydrogen chloride (HC)
b. hydrogen sulfide (H2S)
c. water (H2O)
d. propane (CH3CH2CHs)
1. Soluble in hexane
2. Insoluble in hexane
Answer:
hydrogen chloride (HC)- insoluble in hexane
hydrogen sulfide (H2S)- insoluble in hexane
water (H2O)- insoluble in hexane
propane (CH3CH2CH3)- soluble in hexane
Explanation:
Generally, it is a principle in chemistry that polar solvents dissolve polar substances while nonpolar solvents dissolve nonpolar substances.
This is because, dissolution of a substance in another substance depends on the kind of intermolecular interaction that is possible between the two substances. Hence, ionic substance dissolve in polar solvents due to dipole interactions and nonpolar substances dissolve in nonpolar solvents due to Vanderwaals interaction between the solute and solvent.
Hydrogen chloride, hydrogen sulphide and water are ionic substances hence they can not dissolve in hexane which is a nonpolar substance. However, propane is a nonpolar solvent hence it dissolves in hexane.
Answer: butane (CH3CH2CH2CH3) soluble
hydrogen chloride ( HCl) insoluble
hydrogen sulfide (H_2S) insoluble
water (H_2O) insoluble