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)