Question

(a) Five words are shown in the boxes on the left. Five descriptions are shown in the boxes on the right.
Draw one straight line from each word to its correct description.

(b) A student investigates the reaction between calcium carbonate and dilute hydrochloric acid.
Fig. 2.1 shows the apparatus the student uses.

A salt solution and carbon dioxide are made. The carbon dioxide gas is collected in apparatus A.
(i) State the name of apparatus A shown in Fig. 2.1.

…………………………………………………………………………………………………………………….

(ii) State the name of the salt made.

…………………………………………………………………………………………………………………….
(iii) State the chemical test for carbon dioxide. Include the observation for a positive result.
test ……………………………………………………………………………………………………………………
observation …………………………………………………………………………………………………………

(iv) It takes 50 seconds to collect 90cm$^{3}$ of carbon dioxide gas.
Calculate the rate at which carbon dioxide is made in cm$^{3}$/s.

                                                                                    rate = ………………………………………. cm$^{3}$/ s 

(v) State two changes to the reaction conditions that reduce the rate of reaction.

1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….

(vi) Calcium carbonate has the formula CaCO$_{3}$.
State the number of different elements present in calcium carbonate.

…………………………………………………………………………………………………………………….

▶️Answer/Explanation

Ans: 2(a)

1 correct 1 mark ;
2 correct 2 marks ;
3 or 4 correct 3 marks ;
5 correct 4 marks ;

2(b)(i) measuring cylinder ; 
2(b)(ii) calcium chloride ; 
2(b)(iii) (bubble the gas through) lime water ;

goes milky / cloudy ;

2(b)(iv) 1.8 (cm$^{3}$/ s) ; 

2(b)(v) any two from:

lower temperature (of acid) ;
lower concentration of acid ;
decrease surface area ;

2(b)(vi) 3 ;