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Controlling Chemical Reactions

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Controlling Chemical Reactions

A science team is testing how conditions affect the reaction between an antacid tablet and water. Read the evidence, then solve the team’s reaction-rate challenges. A shorter reaction time means a faster reaction.

Evidence from the lab

The team used the same type and amount of antacid each time. They changed one condition at a time and timed how long bubbling continued.

Condition tested

Setting

Average bubbling time

Water temperature

10°C (cold)

96 seconds

Water temperature

40°C (warm)

54 seconds

Tablet size

Whole tablet

82 seconds

Tablet size

Crushed tablet

39 seconds

Water volume

100 mL water

63 seconds

Water volume

50 mL water

47 seconds

Analyze the evidence

Use the results to explain how reaction conditions affect reaction rate.

1.Which temperature condition made the reaction faster: 10°C water or 40°C water? Support your choice with the reaction times.

2.Why does warmer water usually speed up a chemical reaction? Choose the best explanation.

Its particles move faster and collide more often, so there are more chances for a reaction.
Its particles stop moving and stay together.
Warm water changes every antacid particle into water.
There are fewer collisions between particles in warmer water.

3.The crushed tablet bubbled for 39 seconds, while the whole tablet took 82 seconds. What changed about the tablet, and how did that affect the reaction rate?

4.The team used 50 mL of water instead of 100 mL, and the reaction became faster. In this test, did using less water increase or decrease the solution’s concentration of antacid ingredients? Explain briefly.

5.True or false: In these tests, a longer bubbling time means the reaction happened faster.

TrueFalse

6.Complete the idea: A catalyst can speed up a reaction without being up by the reaction.

7.A student claims, “The warm-water test proves temperature always has a bigger effect than crushing.” Is this a fair conclusion from the results? Explain why or why not.

8.Plan one fair test to find out whether an even warmer water temperature would make the antacid react faster. Name what you would change and two things you would keep the same.

9.A kitchen cook wants sugar to dissolve faster in tea. Give one practical way to increase the rate and explain why it works.