Level 1 NCEA Acids and Bases 2

What variable is being changed in this experiment?

• the concentration of acid

• the concentration of base

• gthe surface area of a reactant

• temperature of the acid

When the temperature of the acid increases - which statement provides the best explanation using particle theory?

• the acid particles expand in the heat

• the acid particles move more quickly

• the acid particles move faster as they have more kinetic energy and more have the required activation energy needed to react.

• particles move more quickly but they do not have enough energy to react

a successful collision between reactant particles happens when

• particles have enough energy (activation energy) to react

• particles collide at the correct angle (orientation)

• particles have enough energy (activation energy) to react and collide at the correct orientation

• particles collide at the correct angle but bounce off each other

a reaction rate increases because

• there are more frequent collision between reactant particles.

• there are more collision between reactant particles

• here are more frequent successful collisions between reactant particles

• there are successful collisions between reactant particles

there is no gas produced in the reaction between a carbonate and an acid at time = 0 because....

• the carbonate is too cold when it is added

• no carbonate has been added to the acid yet

• the acid in the flask is too cold

• the acid particles are colliding unsuccessfully with the carbonate particles.

The rate of reaction is greatest at the start of the reaction because

• the acid concentration is at its highest

• the carbonate is at its hottest

• the acid is cooling down

• the acid is at its coldest and heats up

the reaction rate decreases with time because....

• the acid is getting colder

• the concentration of H⁺ (acid) ions is getting lower

• The concentration of carbonate is getting higher

• The gas is escaping which slows the reaction down

the reaction finishes at different times for the different experiments because

• the acid lost all of it's heat energy and the particles stopped moving

• the experiment ran out of 1 of the reactants at the same point in time

• the two reaction used the same amount of acid and carbonate at the start

• the two reaction have different rates because they are carried out at different temperatures

which of these statements about this experiment is true?

• the indicator is red litmus

• the indicator is blue litmus

• the pH is 3

• the pH is 1

Which of these statements best describes what is happening in the beaker at the start?

• The concentration of OH^- is higher than the concentration of H⁺ ions

• The concentration of OH^- is the same as the concentration of H⁺ ions

• The concentration of H⁺ is lower than the concentration of OH^- ions

• the The concentration of OH^- is lower than the concentration of H⁺ ions