Name of the Student:
Grade/Div : VIII
Name of the Teacher: Sneha Chari
Date: 9th Jan 2021
Subject: Chemistry
Class Test 3
Q.1. (a) ​Type the correct option in the space provided.
1.Which ionic equation represents a more reactive metal displacing a less reactive metal?
D
2. Element ​X​ is a very soft solid.
It reacts violently with water.
A purple flame is seen as it reacts with water.
What is ​X​?
A iodine
B potassium
C aluminium
D zinc
B) Potassium
3. Iron occurs in the ground as iron oxide.
Gold occurs in the ground as the element.
Which statement explains this observation?
A Gold is more reactive than iron.
B Gold oxide is more reactive than iron oxide.
C Iron is more reactive than gold.
D Iron oxide is more reactive than gold oxide.
C) Iron is more reactive than gold
4. Which compound reacts with dilute sulfuric acid?
A magnesium chloride
B potassium carbonate
C sodium sulfate
D zinc nitrate
A) Magnesium chloride
Q.1. (b) ​A student observes what happens when a piece of sodium is added to water, as
shown in Fig.1.1.
Fig. 1.1
During the reaction the student observes that the sodium floats and melts.
The student is told that sodium hydroxide solution is formed and hydrogen gas is given off.
(i) State which information above shows that sodium has a low density.
The information stating that sodium floats on water.
(ii) Write/type the word equation for this reaction.
Sodium + water → sodium hydroxide + hydrogen
(iii) The student makes different observations when a piece of copper is added to water.
Describe these different observations.
1.Copper Sinks Into the water due to high density
2. No fizzing or colour change takes place.(No reaction)
Q.2.(a)​ The student then investigates four other solid metals P, Q, R and S.
He adds equal sized pieces of each metal to cold water and to dilute hydrochloric acid.
Some of his observations are shown in Fig. 2.1.
Fig. 2.1
(i) Use the letters ​P, Q, R​ and S
​ ​ to identify these four metals.
calcium
S
magnesium
P
iron
Q
copper
R
(ii) Identify the gas that is formed when metal ​S​ reacts with dilute hydrochloric acid.
hydrogen
(iii) With reference to the Fig.2.1, arrange the above metals as per reactivity.
1.S (Calcium)
2.P (magnesium)
3.Q (Iron)
4.R (Copper)
(b) ​As per the reactivity of metals, tick (
takes place and put (
) if no reaction occurs.
Magnesium
sulphate solution
Magnesium
Zinc
Iron
Copper
) in the columns where displacement reaction
Zinc sulphate
solution
yes
no
no
no
no
no
Iron sulfate
solution
Copper sulfate
solution
yes
yes
yes
yes
yes
no