Revision work for chemistry Grade-8 First term 2021.
Revision work for chemistry Grade-8
First term 2021.
Chose the best.
What type of reactions can able to change products
back to the their original form?
Reversible reactions Irreversible reactions
What is meant by the term Hydration in Chemistry?
removing water from a substance adding water to a substance adding oxygen to a
substance adding Hydrogen to a substance
What is meant by the term Dehydration in Chemistry?
adding Water to a substance removing water from a substance adding oxygen to a
substance adding Nitrogen to a substance
Which is the correct symbol to show a reversible
reaction?
= → ⇌ >
What is the color and shape of Hydrated Copper
Sulfate ?
White powder blue powder blue crystals white crystals
What is the color and structure of anhydrous copper
sulfate?
white powder black crystlas blue crystals red powder
Dehydration is a
................................... process .
endothermic exothermic
What term is used to describe a chemical reaction
in which the forwards and reverse rates are equal, so the amount of product
remains constant?
Static equilibrium Dynamic equilibrium
What happens if you remove some of one of the
products from a system at dynamic equilibrium?
Less products are made More products are made More reactants are made
What is the effect of increasing the pressure on
the following reaction: 2NO + O2 ⇌ 2NO2?
The yield of NO2 increases The yield of NO2 decreases The reaction is slower
True and False
Changes which can
go backwards or forwards are
called reversible. T
2.
The energy absorbed in the
forward reaction is the same as the energy given
out in the reverse reaction. T
3.
At equilibrium, the rate of the forward reaction and the reverse reaction is the same. T
4.
Dynamic' refers to movement.T
5.
When equilibrium is reached, the amount of each substance stays the same. T
6.
The position of equilibrium shifts to try to cancel
out any changes you introduce.T
7.
We can define a base as a proton acceptor.T
8.
For a strong acid plus a weak alkali, use methyl orange indicator.T
9.
For a weak acid and a strong alkali, use phenolphthalein indicator.T
10. Two non-metal atoms can
both gain Protons by sharing. F
11. Shared electrons form covalent bonds between metal atoms.F
12. Carbon has 2 electrons in its outer shell. F
13. The lst shell is filled by just 8 electrons. F
14. Carbon dioxide is another molecule which
contains a double bond. T
15. Substances with giant covalent structures are not soluble in water.T
16. Diamond and graphite are allotropes of
carbon. T
17. Substances, with low melting points and
boiling points have simple molecular structures. T
18. In general the larger the molecule, the stronger the intermolecular forces.T
1.
Diamond is made from only ------------------- atoms. carbon
2.
Both carbon and hydrogen atoms need to gain ---------------------. electrons
3.
We can define an -------------------- as a proton donor. Acid
4. Hydration is a ----------------------- process. exothermic
5. In a reversible reaction, if forward reaction is
exothermic .Then backward reaction will be------------------. Endothermic
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