Chemistry MCQS

Question 1

endothermic reactions

Answer 1

melting ice, evaporation, thermal decomposition of carbonates, photosynthesis , electrolysis, cooking

Question 2

exothermic reactions

Answer 2

combustion, neutralization, nuclear fission, acid + metals, rusting of iron

Question 3

which metals react with water

Answer 3

potassium, sodium, lithium,, calcium

Question 4

which metals react with acids

Answer 4

all metals up til hydrogen

Question 5

which metals react with oxygen

Answer 5

all excluding gold, silver and platinum

Question 6

thermal decomposition exc. cases

Answer 6

group 1 elements and in nitartes they form nitrites

Question 7

explain exothermic

Answer 7

energy absorbed in bond breaking is less than energy released in bond making

Question 8

formation of acid rain

Answer 8

Many fossil fuels contain sulfur impurities. When these fuels are burned, the sulfur is oxidised to form sulfur dioxide.

S(s) + O2(g) → SO2(g)

This sulfur dioxide then dissolves in droplets of rainwater to form sulfurous acid.

Question 9

What is terylene

Answer 9

A polyester

Question 10

what happens to the temperature of the reaction media during an endothermic reaction?

Answer 10

temperature drops

Question 11

trends in group 1

Answer 11

reacticity increases down the group

m.p and density decreases down the group

Question 12

which is a use of oxygen

Answer 12

to react with methane in a bunsen burner

Question 13

why is carbon monoxide considered to be a pollutant?

Answer 13

it is poisonous

Question 14

does the reaction of an alkali with a carbonate produce CO2

Answer 14

no

Question 15

how to write a polymer

Answer 15

poly(alkene)

NOT ALKANE

Question 16

characteristics of carboxylic acid

Answer 16

pungent smell

colorless

Question 17

is hydration reaction exothermic or endothermic?

Answer 17

exothermic. when we add water back. temp increases

Question 18

what conditions are needed to make steel from the iron produced?

Answer 18

oxygen, heat, calcium oxide (lime)

Question 19

what oxides are released from car exhausts

Answer 19

CO, NO

CO2, NO2, SO2

Question 20

what is a use of stainless steel

Answer 20

in chemical plant bc of its strenght and resistance to corrosion

Question 21

iron explain zones

Answer 21

first layer CaCO3 neatralizes silicon impurity CaO+O2
Zone 3 : Fe2O3 + 3CO —> 3CO2 + 2Fe

Zone 2: CO2 + C —> 2CO

Zone 1: C + O2

slag tapped off
molten iron tapped off

Question 22

iron to steel

Answer 22

tilting furnace
O2
CAO
Heat
carbon sulfur phosphorus silicon removed

Question 23

stainless steel

Answer 23

chromium and nickel