conservation of mass

conservation of mass

Multiple Choice

Tick the correct statement below. [1]

In a chemical reaction...

• atoms and mass are lost.

• atoms and mass are gained.

• atoms are rearranged and mass is conserved.

Multiple Choice

by burning 11,2 gram iron we can get 14,4 g iron(II) oxide.

Find how much oxygen is required for the reaction. The mass of iron

and oxygen together should be equal to the mass of iron oxide after

reaction

• 1.6 g

• 3.2 g

• 25.6 g

• 6.4

Multiple Choice

The conservation of mass rule can be applied to other reactions also.

By keeping this in mind, solve the question below.

We can get table salt by combining sodium and chlorine. Find the mass of

chlorine gas used if the mass of sodium used is 4,6 gram and the mass

of salt produced is 11,7 gram. Here the mass of sodium and chlorine is

equal to the mass of the table salt at the end.

• 3.55 g

• 16.3 g

• 7.1 g

• 5.6 g

Multiple Choice

Sometimes the total mass of the substance on the dish seems to get

less. Actually, some mass is released as a gas. Please solve the

example below by considering it.

Calcium carbonate can produce calcium oxide and carbon dioxide.

Initial mass of calcium carbonate is 10 gram and the mass of the

calcium oxide is 5,6 gram. Find the mass of carbon dioxide released

into the atmosphere.

• 4.4 g

• 3.2 g

• 15.6 g

• 56 g

Open Ended

A pupil heated 1.24g of copper carbonate strongly.

The chemical reaction, which took place, is represented by the equation:

CuCO₃ (s) ==> CuO(s) + CO₂(g)

After the solid, which remained, had cooled, he weighed it. He found that its

mass was 0.80g

Why did the pupil find a decrease in mass in this experiment?

Multiple Choice

Write a word equation for the reaction, which takes place when

the magnesium burns in oxygen.

• magnesium+magnesium oxide==> magnesium+oxygen

• magnesium oxide + oxygen==>magnesium

• magnesium +magnesium oxide==> oxygen

• magnesium + oxygen==> magnesium oxide

Multiple Choice

when carbon and oxygen reacts, two oxygen atom combine with 1 carbon atom. if there are 4 carbon and 8 oxygen atoms at the beginning of the reaction, how many carbon dioxide molecules will be formed at the end.

• 2

• 4

• 6

• 8

Multiple Choice

the reaction between carbon and oxygen is as follows:

carbon+ oxygen==> carbon dioxide

write which one is the product here

• carbon

• oxygen

• carbon dioxide

• none of the above

Multiple Choice

12 g of carbon reacted with 32 g of oxygen. What mass of carbon dioxide was formed? Circle the correct

answer.

• 12

• 24

• 32

• 44

Multiple Choice

In an experiment, a student burnt magnesium ribbon in air. He

found that the mass of the powder formed was greater than the

original mass of the ribbon.

• there is a magnesium added during the reaction

• the oxygen in the air combined with magnesium

• the scale is not correctly measuring

• the mass of the magnesium can change from time to time.

Multiple Choice

This diagram below shows the reaction between marble chips and acid

This is the word equation for the reaction:

hydrochloric acid+ calcium carbonate —> calcium chloride+ carbon dioxide +water

the initial mass of the reactants measured as 180 gram. what woud you expect the total mass of the calcium chloride and water.

• more than 180 gram

• less than 180 gram

• 180 gram

Multiple Choice

If you heat a piece of copper, it combines with oxygen from the air to form a black layer of copper oxide. Write a word equation for this reaction.

• copper + copper oxide==> oxygen

• copper oxide+ oxygen==> copper

• copper + oxygen ==> copper oxide

Multiple Choice

how will the mass of the copper will change when it combines with oxygen and forms copper oxide

• increase

• decrease

• doesnt change

Multiple Choice

5 grams of iron combines with 3 grams of sulfur and forms iron sulfide. calculate the mass of the iron sulfide that is formed.

• 0.4 gram

• 2 grams

• 8 grams

• 2.5 grams

Multiple Choice

8 grams of aluminium combines with oxygen in the air and forms 11 grams of aluminium oxide. how much oxygen combined with aluminium.

• 19 grams

• 3 grams

• 11/8 grams

• 8/11 grams

Multiple Choice

in which of the reactions below the mass increases?

• A piece of magnesium ribbon

  is burnt in oxygen

• A piece of ice is left to

  melt in a beaker

• Sugar is stirred into a

  beaker of water

• Marble chips are placed into

  hydrochloric acid and a gas escapes

• One liquid is added to another liquid

Multiple Choice

in which of the reactions below the mass decreases?

• A piece of magnesium ribbon

  is burnt in oxygen

• A piece of ice is left to

  melt in a beaker

• Sugar is stirred into a

  beaker of water

• Marble chips are placed into

  hydrochloric acid and a gas escapes

• One liquid is added to another liquid