6) Food Chemistry

Question 1

What is a mixture?

Answer 1

A mixture is formed when two or more substances are mixed.

Question 2

What are the 3 common units of volume and their symbols?

Answer 2

Question 3

Convert 1m3 to cm3

Answer 3

1m3 = 1 000 000 cm3

Question 4

Convert 1cm3 to ml

Answer 4

1cm3 = 1 ml

Question 5

Describe how to use a measuring cylinder to measure the volume of a soild.

Answer 5

To measure the vol. of a solid, take 2 readings of liquid.
* Once before the solid is placed inside the liquid and once after the solid is placed inside the liquid.
* Take the difference between the two readings to get the vol. of the solid.

Question 6

State the 5 separation techniques we have learnt.

Answer 6

(a) dissolving
(b) filtration
(c) evaporation
(d) distillation
(e) paper chromatography

Question 7

What are the parts labelled A and B used in filtration?

filtration process

Answer 7

A: residue
B: filtrate

Question 8

What are the parts labelled A , B and C used in dissolving?

dissolving process

Answer 8

A: solvent
B: solute
C: solution

Question 9

What type of mixture can evaporation separate?

Answer 9

A solution

e.g. Sea water is a solution (a mixture of salt and water).
Evaporation removes water and return the salt.

Question 10

What are the parts labelled A used in distillation?

distillation process

Answer 10

A: distillate

Question 11

What is the purpose of the condenser?

Answer 11

To cool down the gas that escape from the distillation flask and turn it back into liquid.

Question 12

What is the purpose of paper chromatograpy?

paper chromatography

Answer 12

To separate mixtures such as inks and food colourings

Question 13

What is a chemical reaction?

In other word, how can I tell if there is a chemical rxn taking place?

Answer 13

A chemical reaction is a process that leads to the formation of new substances

The new substance is also known as products.

Question 14

Give 2 examples of chemical reactions you have learnt in this chapter.

There are 4 examples.

Answer 14

1. cooking of food
2. burning of fuel
3. decaying of food
4. rusting of iron

Question 15

The word equation for photosynthesis is written below
light and chlorophyll
carbon dioxide + water ——————————-> food + oxygen

Identify the reactants and products in this chemical reaction.

Answer 15

reactants: carbon dioxide, water
products: food, oxygen

Question 16

A blue and red litmus paper is used on an acid.
What is the result of the test?

Answer 16

Blue litmus paper turns red.
Red litmus paper remains red.

Question 17

A blue and red litmus paper is used on an alkali.
What is the result of the test?

Answer 17

Red litmus paper turns blue.
Blue litmus paper remains blue.

Question 18

A blue and red litmus paper is used on a neutral solution.
What is the result of the test?

Answer 18

Red litmus paper remains red.
Blue litmus paper remains blue.

Question 19

A universal indicator solution is used on an alkali.
What is the result of the test? Use the universal indicator chart to help you.

universal indicator chart

Answer 19

It can be either green, blue or purple.

The strength of the alkali determine the colour.

Question 20

This is one of the reaction with acid:
acid + metal —> salt + ______________

Identify the missing product.

Answer 20

hydrogen gas

Question 21

This is one of the reaction with acid:
acid + carbonate —> salt + ______________ + ________________

Identify the missing products.

Answer 21

carbon dioxide gas and water

Question 22

This is one of the reaction with acid:
acid + base —> salt + ______________ + ________________

Identify the missing product.

Base is an example of alkali.

This reaction is also known as neutralisation,

Answer 22

water