Chemistry Comp-II
Which expression represents the pH of a solution?
-log[H30+]
A 20.0 mL sample of potassium hydroxide (KOH) solution is titrated to the equivalence point with 23.5 mL of 0.350 M hydrobromic acid (HBr) solution. What is the molarity of the potassium hydroxide solution?
.41
Calculate the boiling-point elevation of a solution made from 15.0 g of a nonelectrolyte solute and 250.0 g of water. The molar mass of the solute is 50.0 g and Kb=0.51°C/m.
.612
What is the molarity of a solution that contains 0.202 mol KCl in 7.98 L solution?
0.0253 M
How many moles of HCl are present in 0.70 L of a 0.33 M HCl solution? (molar mass of HCl = 36.46 g/mol)
0.23 mol
What is the molarity of an NaOH solution if 4.37 mL is titrated by 11.1 mL of 0.0904 M HNO3?
0.230 M
What is the boiling-point elevation of a solution made from 10.0 g of a nonelectrolyte solute and 300.0 g of water? The molar mass of the solute is 50.0 g and the molal boiling-point constant for water is 0.51°C/m.
0.34 degrees celcius
What is the boiling-point elevation of a solution made from 20.0 g of a nonelectrolyte solute and 300.0 g of water? The molar mass of the solute is 50.0 g and Kb = 0.51°C/m.
0.68 degrees celcius
What is the molarity of an HCl solution if 125 mL is neutralized in a titration by 76.0 mL of 1.22 M KOH?
0.742 M
The pH of a solution is 9.0. What is its H3O+ concentration?
1 * 10^-9 M
Which coefficients correctly balance the formula equation CaO + H2O ---> Ca(OH)2
1, 1, 1
Which coefficients correctly balance the formula equation NH4NO2(s) ---> N2(g) + H2O(I)
1, 1, 2
200. g of a nonelectrolyte is dissolved in 1.00 kg of water. The boiling point of the solution is then measured to be 101.5°C. What is the molar mass of the compound? The Kb for water is 0.51°C/m.
1.004 g/mol
What is the molality of a solution that contains 5.10 mol KNO3 in 4.47 kg water? (molar mass of KNO3 = 101.11 g/mol)
1.14
Use the table below to answer the following questions. Element Symbol Atomic Mass Bromine Br 79.90 Calcium Ca 40.08 Carbon C 12.01 Chlorine Cl 35.45 Cobalt Co 58.93 Copper Cu 63.55 Fluorine F 19.00 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Magnesium Mg 24.30 Mercury Hg 200.59 Nitrogen N 14.01 Oxygen O 15.00 Potassium K 39.10 Sodium Na 22.99 Sulfur S 32.01 For the reaction represented by the equation 2H2 + O2 → 2H2O, how many grams of water are produced from 6 mol of hydrogen?
108 g
The concentration of a water solution of NaCl is 2.48 m, and it contains 806 g of water. How much NaCl is in the solution? (molar mass of NaCl = 58.44 g/mol)
117 g
For the reaction represented by the equation Cl2 + 2KBr → 2KCl + Br2, how many grams of potassium chloride can be produced from 300. g each of chlorine and potassium bromide?
188 g
In the reaction represented by the equation N2 + 3H2 → 2NH3, what is the mole ratio of nitrogen to ammonia?
1:2
The Haber process for producing ammonia commercially is represented by the equation N2(g) + 3H2(g) → 2NH3(g). To completely convert 9.0 mol hydrogen gas to ammonia gas, how many moles of nitrogen gas are required?
3.0 mol
What is the pH of a 10^-4 M HCl solution?
4
If [H3O+] = 8.26 × 10-5 M, what is the pH of the solution?
4.083
The freezing point of an aqueous solution that contains a nonelectrolyte is -8.0°C. What is the molal concentration of the solution? The molal freezing-point constant for water is -1.86°C/m.
4.3 m
What is the hydronium ion concentration of a solution whose pH is 7.30?
5.0 * 10^-8 M
What is the pH of a neutral solution at 25°C?
7
What is the pH of a 10-5 M KOH solution?
9
For the reaction represented by the equation SO3 + H2O → H2SO4, calculate the percentage yield if 500. g of sulfur trioxide react with excess water to produce 575 g of sulfuric acid.
93.9%
What is the small whole number that appears in front of a formula in a chemical equation?
Coefficient
In writing a chemical equation that produces hydrogen gas, the correct representation of hydrogen gas is
H2
Which compound is produced by a neutralization?
H2O(l)
The substances produced when KOH(aq) neutralizes HCl(aq) are
H2O(l) and KCl(aq)
What is the general formula for ethers?
R-O-R
Three experiments that have identical conditions were performed to measure the initial rate of decomposition of ammonia on a platinum surface:. The results for the three experiments in which only the NH3 concentration was varied are as follows: Experiment [NH3] (M) Rate (M/s) 1 0.040 4.5 10-2 2 0.080 9.0 10-2 3 0.120 1.35 10-1 Write the rate law for the reaction. Find the value and units of the specific rate Constant
R= k[NH3] ----> 1.125
What is the balanced equation for the combustion of sulfur?
S(s) + O2(g) ---> SO2(g)
Sulfur dioxide is commonly formed by the burning of fossil fuels. It combines with additional oxygen to form sulfur trioxide. Write an equilibrium expression for the reaction represented by the following equation. 2SO2(g) + O2(g) 2SO3(g)
[SO3]^2 / [SO2]^2 [O2]
In the equation, what represents the concentrations of the products?
[W] and [X]
In the equation , what represents the concentrations of the reactants?
[Y] and [Z]
Which of the following burns most slowly?
a large lump of coal
When a solid produced by a chemical reaction separates from the solution it is called
a precipitate
Which of the following is a homogeneous mixture?
a suger-water solution
Which of the following is likely to produce crystals if disturbed?
a supersaturated solution
Which mixture contains visible particles that settle out unless the mixture is stirred?
a suspension
An amphoteric species is one that reacts as a(n)
acid or base
Hydrocarbons in which carbon atoms are connected by only single bonds in straight chains or branched chains are called
alkanes
A metal solution is a(n)
alloy
The solubility of a substance at a given temperature is generally expressed as
amount of solute per amount of solvent
When the chemical equilibrium expression is written, coefficients from the equation for the reaction
appear as exponents
Bases taste
bitter
The diversity of organic compounds is so great because carbon
compounds have many isomers
A sample of a substance burns more rapidly in pure oxygen than in air. Which factor is most responsible for this high rate of reaction?
concentration of the reactants
In what kind of reaction does a single compound produce two or more simpler substances?
decomposition reaction
In what kind of reaction does one element replace a similar element in a compound?
displacement reaction
In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds?
double displacement reaction
The reaction represented by the equation Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) is a
double-displacement reaction
The pH b a basic solution is
greater than 7
Raising the temperature of reactants in a system
increase the average kinetic energy of the molecules
Raising the temperature of gas particles
increases collision energy but does not increase favorability of orientation
If [H3O+] of a solution is greater than [OH-], the solution
is always acidic
If [H3O+] of a solution is less than [OH-], the solution
is always basic
A solute crystal is dropped into a solution containing dissolved solute. It falls to the bottom of the beaker and does not dissolve after vigorous stirring. What does this indicate about the solution?
it is probably saturated
The pH of an acidic solution is
less than 7
A chemical reaction involving substances A and B stops when B is completely used. B is the
limiting reactant
Which reactant controls the amount of product formed in a chemical reaction?
limiting reactant
An acid-base titration involves a
neutralization reaction
"Like dissolves like" is a very general rule used for predicting whether
one substance will form a solution with another
What is the ratio of the actual yield to the theoretical yield, multiplied by 100%?
percentage yield
In the expression "like dissolves like," the word like refers to similarity in molecular
polarity
Which of the following will dissolve most rapidly?
powdered sugar and water
According to the rate law, the rate of a reaction and the concentration of reactants are always
proportional
The reaction represented by the equation Mg(s) + 2HCl(aq) → H2(g) + MgCl2(aq) is a
single-displacement reaction
Bases feel
slippery
The Tyndall effect is used to distinguish between
solutions and colloids
Acids taste
sour
In what kind of reaction do two or more substances combine to form a new compound?
synthesis reaction
The reaction represented by the equation 2Mg(s) + O2(g) ---> 2MgO(s) is a
synthesis reaction
Colligative properties depend on
the concentration of solute particles
Which of the following affects reaction rate?
the nature of reactants surface area of the reactants temperature
Indicators are classified into three types according to
the pH at which they change color
If the concentration of reactants is higher,
the reaction rate is generally higher
If the temperature of the reactants is lower,
the reaction rate is generally lower
Isomers are compounds that have
the same molecular formula but different structures
What process measures the amount of a solution of known concentration required to react with a measured amount of a solution of unknown concentration?
titration
A heterogeneous mixture always contains
two or more substances that are visibly distinguishable
Which of the following does not increase the rate of dissolving a solid in water?
using larger pieces of solid
In an equation, the symbol for a substance in water solution is followed by
(aq)