Experimental Design Chemistry

In an experiment, a student needs to measure out 36.50 cm³ of a solution.

Which piece of apparatus would measure this volume most accurately?

•  beaker

•  burette

• measuring cylinder

•  pipette

A student investigates the rate of reaction between a solid and liquid. During the reaction, the student measures the volume of gas released.

The student is provided with a conical flask, a pipette and a balance.

Which additional apparatus is required? ​ ​

(a)  

• stopwatch

• gas syringe

• thermometer

A gas turns moist red litmus paper blue, is soluble in water and is less dense than air. Which diagram shows the correct way of drying and collecting the gas?

• A

• B

• C

• D

A student follows the rate of the reaction when 0.19 g of magnesium reacts with excess acid at room temperature and pressure.

What is most suitable for measuring the volume of gas produced at different times during this experiment?

• 50 cm3 gas syringe

• inverted 250 cm3 measuring cylinder filled with water

• inverted 50 cm3 burette filled with water

• place an apparatus on a balance and measure the loss in mass

Answer explanation

A common incorrect choice was option A. These candidates did not use the data to calculate the volume of

gas produced in the experiment (190 cm3), which is greater than the capacity of the gas syringe in option A.

A student wishes to add exactly 13.20 cm³ of acid to exactly 25.0 cm³ of an alkali as part of an experiment. Which apparatus should the student use to measure these volumes?

• acid: pipette

  alkali burette

• acid: burette

  alkali: pipette

• acid: measuring cylinder

  alkali burette

• acid: burette

  alkali : measuring cylinder

Answer explanation

Pipette - fixed volume of gases (20.0 or 25.0 cm3)

Burette - accurate to nearest 0.05 cm3

Which apparatus would be most suitable for measuring 45.00 cm³ of sodium hydroxide?

Answer explanation

2 d.p accuracy

What method is used to collect carbon dioxide?

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• 
• 

Chlorine cannot be collected by displacement of water. Why?

• Chlorine is insoluble in water.

• Chlorine is soluble in water.

• Chlorine is denser than air.

• Chlorine is less dense than air.

Concentrated sulfuric acid is often used as a drying agent to obtain a dry sample of a moist gas. However, it is not suitable to dry a sample of ammonia gas. Why is this so?

• Ammonia is soluble in water.

• Ammonia is insoluble in water.

• Ammonia will react with sulfuric acid.

• The products formed will be too toxic.