Chemistry chapter 6

Consider the reaction, C2H4(g) + H2(g) → C2H6(g), where ΔH = -137 kJ. How many kilojoules are released when 3.5 mol of C2H4 reacts? 137 kJ are released 570 kJ are released 480 kJ are released 2.0 × 103 kJ are released

480 kJ are released

Walking at a brisk pace burns off about 280 Cal/h. How long would you have to walk to burn off the Calories obtained from eating a candy bar that contained 3 g of protein, 12 g of fat, and 28 g of carbohydrates? 55 minutes 230 minutes 50 minutes 210 minutes

50 minutes

Consider the reaction: N2(g) + O2(g) 2 NO(g). If [N2] = 0.520 M, [O2] = 0.0662 M, and [NO] = 0.00956 at equilibrium, what is the value of K? 3.60 0.278 377 0.00265

0.00265

Consider the reaction: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), where ΔH = -531 kcal/mol. How much heat is released when 3.40 × 1020 molecules of C3H8(g) is burned? 3.33 kcal 0.300 kcal 6.40 × 1017 kcal 1.50 kcal

0.300 kcal

Which quantity represents the largest amount of stored energy? 10 grams of fat 10 grams of carbohydrate 10 grams of protein 5 grams of carbohydrate plus 5 grams of protein 5 grams of protein plus 5 grams of fat

10 grams of fat

Consider the combustion reaction of propane: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), where ΔH = -531 kcal. If 6.70 × 104 kcal of energy is released in the reaction, how many grams of oxygen were consumed? 63.1 g of O2 2.02 × 104 g of O2 12.6 g of O2 404 g of O2

2.02 × 104 g of O2

Consider the reaction: PCl3(g) + Cl2(g) PCl5(g). If [PCl3] = 0.78 M, [Cl2] = 0.44 M, and [PCl5] = 0.88 at equilibrium, what is the value of K? 0.39 1.4 2.6 0.72

2.6

A peanut butter and jelly sandwich contains 9.00 g of fat, 6.00 g of protein, and 25.0 g of carbohydrate. How many Calories does this sandwich provide? 205 Cal 360 Cal 160 Cal 260 Cal 190 Cal

205 Cal

Consider the combustion reaction of propane: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), where ΔH = -531 kcal. If 1.24 × 105 kcal of energy is released in the reaction, how many moles of propane were burned? 234 mol of C3H8 6.58 × 107 mol of C3H8 0.00428 mol of C3H8 0.0179 mol of C3H8

234 mol of C3H8

Consider the reaction, C2H4(g) + H2(g) → C2H6(g), where ΔH = -137 kJ. How many kilojoules are released when 55.3 g of C2H4 reacts? 137 kJ are released 270. kJ are released 1.13 × 103 kJ are released 7.58 × 103 kJ are released

270. kJ are released

Consider the reaction, 3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g), where ΔH = -137 kJ. How many kilojoules are released when 92.3 g of NO2 reacts? 2.01 kJ are released 2.75 × 102 kJ are released 91.6 kJ are released 1.26 × 104 kJ are released

91.6 kJ are released

Which statement about catalysts is NOT true? A catalyst increases the rate of a chemical reaction. A catalyst lowers the activation energy of a chemical reaction. A catalyst lowers the ΔH of a chemical reaction. A catalyst is recovered unchanged in the reaction it catalyzes.

A catalyst lowers the ΔH of a chemical reaction.

Which of the following will increase the rate of a reaction? Increasing the temperature Increasing the concentration of a reactant Adding a catalyst Ensuring that the reactants are properly aligned when they collide All of these changes will increase the rate of a reaction.

All of these changes will increase the rate of a reaction.

Which value (if any) in each pair corresponds to a faster reaction? Ea = 1 kcal Ea = 10 kcal Ea = 100 kcal Reaction rate is independent of Ea value.

Ea = 1 kcal

Which value (if any) in each pair corresponds to a slower reaction? Multiple Choice Ea = 1 kcal Ea = 10 kcal Ea = 100 kcal Reaction rate is independent of Ea value.

Ea = 100 kcal

Which term correctly describes a reaction in which the energy of the products is higher than the energy of the reactants? Oxidation-reduction Endothermic Exothermic Combustion

Endothermic

Which K value below is consistent with an equilibrium system in which the reactants are favored? Multiple Choice K = 1 K = 1.8 x 103 K = 3.7 x 10-8 K = 500

K = 3.7 x 10-8

Which K value below is consistent with an equilibrium system in which the products are favored? K = 1 K = 5.2 x 104 K = 3.8 x 10-6 K = 0.100

K = 5.2 x 104

Consider the reaction: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), where ΔH = -531 kcal. Which statement concerning this reaction is true? Heat is absorbed. The bonds formed in the products are stronger than the bonds broken in the reactants. The products are higher in energy than the reactants. The reaction is endothermic.

The bonds formed in the products are stronger than the bonds broken in the reactants.

Consider the reversible reaction at equilibrium: N2(g) + O2(g) 2 NO(g). What is the effect of removing some N2(g) from the equilibrium system? The concentration of O2(g) increases The concentration of O2(g) decreases The concentration of NO(g) increases The equilibrium system shifts to the right

The concentration of O2(g) increases

The hydrolysis of sucrose depicted below has K = 1.4 × 105. Which of the following is a reasonable assumption about this reaction once equilibrium is established? sucrose + H2O glucose + fructose The equilibrium mixture contains equal amounts of sucrose, glucose, and fructose. The equilibrium mixture contains mostly glucose and fructose. The equilibrium mixture contains mostly sucrose. The equilibrium shifts to the left due to the high value for K.

The equilibrium mixture contains mostly glucose and fructose.

When the pressure of a reaction at equilibrium decreases, in which direction does the equilibrium shift? The equilibrium shifts in the direction that increases the number of moles of gas. The equilibrium shifts in the direction that decreases the number of moles of gas. The equilibrium does not shift. The equilibrium shifts always shifts to the right. The equilibrium shifts always shifts to the left.

The equilibrium shifts in the direction that increases the number of moles of gas.

The rusting of iron is described by the reaction: 4 Fe(s) + 3 O2(g) → 2 Fe2O3(s). The formation of rust on an exposed piece of iron typically takes several months. Which of the following is NOT a reasonable assumption about this chemical reaction? The formation of rust has a low reaction rate. The formation of rust has a low activation energy. The formation of rust would occur more slowly at higher altitudes where the concentration of oxygen is lower. The formation of rust would occur faster in the warmer summer months than in the cooler winter months.

The formation of rust has a low activation energy.

The rate of a chemical reaction increases with an increase in the concentration of one or more reactants. This is best explained by which statement? The higher concentration of reactants increases the potential energy of the molecules. The higher concentration of reactants increases the activation energy of the reaction. The higher concentration of reactants increases the temperature of the molecules. The higher concentration of reactants increases the frequency of collisions between molecules.

The higher concentration of reactants increases the frequency of collisions between molecules.

One step in the metabolism of glucose is depicted below. Which statement best describes how the equilibrium system would respond if the amount of dihydroxyacetone phosphate is decreased? The system would shift to the left, consuming more dihydroxyacetone phosphate. The system would shift to the right, producing more dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. The system would shift to the left, producing more fructose 1,6-bisphosphate. The system would shift to the right, consuming some glyceraldehyde 3-phosphate and producing more dihydroxyacetone phosphate.

The system would shift to the right, producing more dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.

In the reaction: 2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g), increasing the concentration of C2H6(g) will ________. increase the activation energy of the reaction decrease the activation energy of the reaction decrease the ΔH of the reaction increase the reaction rate decrease the reaction rate

increase the reaction rate

For an endothermic reaction at equilibrium, increasing the temperature ________. does not shift the equilibrium since K is a constant increases the rate of the reverse reaction to form more reactants increases the rate of the forward reaction to form more products increases the rate of the reverse reaction to form more products

increases the rate of the forward reaction to form more products

Catalysts accelerate a reaction by ________. Multiple Choice lowering the enthalpy of the reaction lowering the energy of activation raising the enthalpy of the reaction raising the energy of activation

lowering the energy of activation

A catalytic converter uses a catalyst to catalyze three reactions that clean up the exhaust from an auto engine. Which element is not used as a catalyst in catalytic converters? Platinum Rhodium Sulfur Palladium

sulfur

A reversible reaction has reached equilibrium when which condition is established? the reverse reaction begins to occur the concentrations of reactants and products become equal all of the reactants have been converted into products the forward and reverse reaction rates become equal

the forward and reverse reaction rates become equal

An equilibrium constant with a value of 8.0 × 106 indicates that at equilibrium ________. the reactants are favored the products are favored approximately equal concentrations of reactants and products are present there are more reactants present than products

the products are favored

An equilibrium constant with a value of 1.5 × 10-9 indicates that at equilibrium ________. the reactants are favored the products are favored approximately equal concentrations of reactants and products are present there are more products present than reactants

the reactants are favored