chem mc HELP

1. What is the definition of the temperature of a substance ?
A. the total heat content of a substance
B. the speed of the fastest particles in the substance
C. the speed of the slowest particles in the substance, subtracted from the from the speed of the fastest particles in the substance
D. the heat capacity of the substance times its mass
E. the average kinetic energy of system

2. which statement describes an exothermic reaction?
A.the energy absorbed in bond breaking is more than the energy released in bond formation.
B. the energy absorbed in bond breaking is less than the energy released in bond formation.
C. the system absorbs energy D. the surroundings cool down.
E. the potential energy of the reactants is less than the potential energy of the products. .

3. in an exothermic reaction, . .H'rxn is ....
A. always positive B.always negative C.negative D.zero E. not possible measure

4.which statement dose not describe an endothermin reaction
A.the surroundings cool down. B. . .H'rxn is positive. C.heat is released by the system.
D. heat is absorbed by the system. E. the products is greater than the potential energy of the reactants.

5. which statement dose not represent a rate?
A. the speed of a car is 45 km/h B. the half-life of an element is 12.4h. C. a family consumes 4L of milk every threee days. D. it takes 15 min to the store.
E. A cat eats three cans of wet food per week.

6. the initial rate of production of Br2 gas in the following reaction is 0.0750 mol/(L.S). what is the rate of
loss of HBr gas? 4HBr(g)+O2(g)-->2Br2(g)+2H2O(g)
A. 0.0188 mol/(L.s) b. 0.0375 mol/(L.s) C.0.0750 mol/(L.s) D.0.150 mol/(L.s) E. 0.300mol/(L.s)

7.Which factor will not affect the rate of the following reaction?
A. the addition of a catalyst B. an increase in pressure C. an increase in the concentration of AgNO3(aq)
D. an in crease in temperature E. all of these factors will have a strong effect on the rate of the reaction