Rates of Reaction 1.1 internal investigation MAGS

If you investigate how different surface area calcium carbonate affects the rate of chemical reaction, what is the dependent variable.

• Time

• Rate

• Calcium carbonate

• Surface area

The dependent variable is:

• The one that is measured in the investigation

• The one you change in the investigation

• Rate of reaction

Which of these indicates a way to complete an experiment more accurately?

• Using a measuring cylinder instead of a beaker to measure a volume

• Using scales to measure the mass of a solid instead of using a pea sized amount

• Using the same sized flask/beaker each time so the depth of solution is the same

• Repeating the experiment 3 times.

In an investigation of adding magnesium metal to acid what would be the best ways to time how long it takes to react?

• Use a stopwatch and stop when an X placed under it disappears

• Time until bubbles stop forming

• Timing until the magnesium has disappeared

• None of these will work

• Timing until the colour changes to green and is neutralised

Which variable is the one you change on purpose in an investigation? (use one word to describe it)

(a)  

When you increase the surface area what do you expect to happen to time AND rate?

• time decreases so rate increases

• time increases so rate decreases

• time increases so rate increases

• time decreases so rate decreases

Which of these describes an increase in surface area?

• Bigger masses of solid compared to smaller masses

• Bigger pieces of solid compared to smaller pieces

• Grinding up a solid

When concentration of HCl acid increases what is the effect on the particles?

• More particles are exposed

• More particles of HCl are in the volume given

• Less HCl particles are found in the volume given

• The HCl particles move faster with more kinetic energy

• The activation energy is lowered

Which of these describes correctly changing the independent variable of Concentration of an acid.

• Measuring out different volumes of acid e.g. 2 mL, 3 mL, 4 mL.

• Grinding up solid particles of acid into smaller pieces

• Adding different volumes of acid and topping up with water to the same total volume. e.g. 5mL acid+5mL water, 2mL acid+8 mL water.

• None of the above describe changing concentration

Select all of the options that increase the reliability of an experiment:

• Carrying out an investigation 3 times

• Plotting a graph to look for trends

• Looking and identifying outliers and excluding them from averages

• Using a measuring cylinder to measure volumes of liquid