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7. (a) Air contains several gaseous elements - Edexcel - GCSE Chemistry - Question 7 - 2020 - Paper 1
Question 7
7. (a) Air contains several gaseous elements. Which of these shows the three most common gaseous elements in air, listed in order from the most common to the least ... show full transcript
Worked Solution & Example Answer:7. (a) Air contains several gaseous elements - Edexcel - GCSE Chemistry - Question 7 - 2020 - Paper 1
Step 1
Which of these shows the three most common gaseous elements in air, listed in order from the most common to the least common?
Answer
The three most common gaseous elements in air, listed in order from the most common to the least common, are: 1. Nitrogen 2. Oxygen 3. Argon. Therefore, the correct answer is D: nitrogen, oxygen, argon.
Step 2
Use the results to calculate the density of argon in g cm⁻³.
Answer
To find the density, we first calculate the mass of argon:
Mass of argon = Mass of stopper and flask full of argon - Mass of stopper and flask
Mass of argon = 79.120 g - 78.639 g = 0.481 g
Now, we can use the density formula:
Substituting the values:
This can be rounded to 0.00192 g cm⁻³.