This question is about gases - Edexcel - GCSE Chemistry - Question 3 - 2022 - Paper 1
Question 3
This question is about gases.
(a) When sodium is added to water, hydrogen gas is produced.
Which observation shows that a gas has been produced?
A a white pre... show full transcript
Worked Solution & Example Answer:This question is about gases - Edexcel - GCSE Chemistry - Question 3 - 2022 - Paper 1
Step 1
When sodium is added to water, hydrogen gas is produced.
Which observation shows that a gas has been produced?
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Answer
The correct observation indicating the production of gas is option B: effervescence is seen. This is because the release of hydrogen gas when sodium reacts with water causes bubbles, which is a clear sign of gas formation.
Step 2
Some damp litmus paper is placed in a gas.
Which gas bleaches damp litmus paper?
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Answer
The gas that bleaches damp litmus paper is option B: chlorine. Chlorine gas is a strong oxidizing agent and reacts with the dye in litmus paper, leading to bleaching.
Step 3
When calcium carbonate is heated it decomposes.
Calculate the mass of carbon dioxide that has been released.
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Answer
To find the mass of carbon dioxide (CO2) released, we start with the initial mass of calcium carbonate (CaCO3), which is 5.000g. The mass of the solid remaining after heating is 2.800g.
