A student used the apparatus in Figure 7 to investigate the rate of the reaction between a metal and dilute hydrochloric acid - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2022 - Paper 1
Question 5
A student used the apparatus in Figure 7 to investigate the rate of the reaction between a metal and dilute hydrochloric acid.
Pieces of the metal were placed in di... show full transcript
Worked Solution & Example Answer:A student used the apparatus in Figure 7 to investigate the rate of the reaction between a metal and dilute hydrochloric acid - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2022 - Paper 1
Step 1
i. Name a piece of apparatus that would be better to measure the volume of gas produced, instead of the 250 cm³ measuring cylinder.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A suitable piece of apparatus would be a gas syringe.
Reason: A gas syringe allows for more accurate measurement of gas volume due to its smaller graduations and higher resolution.
Step 2
ii. Calculate the mean rate of production of hydrogen over the first 90 seconds, in cm³ per second.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To find the mean rate of production of hydrogen:
From the graph, the volume measured at 90 seconds is 29 cm³.
The mean rate can be calculated as:
Rate=TimeVolume=90 seconds29 cm3=0.3222 cm3 per second.
Step 3
iii. The student measured the volume of gas for 10 minutes. State why the measurements could have been stopped at 9 minutes.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The measurements could have been stopped at 9 minutes because the volume of gas was constant, indicating that the reaction had finished.
Step 4
i) Explain why the rate of reaction increases when the concentration of acid is increased.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The rate of reaction increases with higher acid concentration because there are more reactant particles present, leading to more frequent collisions. This increases the likelihood of successful collisions, resulting in a faster reaction.
Step 5
ii) Another student suggests four ways of increasing the rate of this reaction. Which one is correct?
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The correct option is D: use the same metal but in a powdered form. This increases the surface area, leading to more frequent collisions and a faster reaction.
Step 6
Describe how the student can make small and medium sized marble chips from large chips.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The student can crush the large chips into smaller pieces using a pestle and mortar. Alternatively, they can chop or slice the chips into smaller pieces. To ensure uniform sizes, they can use sieves to separate different sized chips or sort the chips by size.
