6) Food Chemistry Flashcards
What is a mixture?
A mixture is formed when two or more substances are mixed.
What are the 3 common units of volume and their symbols?
Convert 1m3 to cm3
1m3 = 1 000 000 cm3
Convert 1cm3 to ml
1cm3 = 1 ml
Describe how to use a measuring cylinder to measure the volume of a soild.
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.
State the 5 separation techniques we have learnt.
(a) dissolving
(b) filtration
(c) evaporation
(d) distillation
(e) paper chromatography
What are the parts labelled A and B used in filtration?
A: residue
B: filtrate
What are the parts labelled A , B and C used in dissolving?
A: solvent
B: solute
C: solution
What type of mixture can evaporation separate?
A solution
e.g. Sea water is a solution (a mixture of salt and water).
Evaporation removes water and return the salt.
What are the parts labelled A used in distillation?
A: distillate
What is the purpose of the condenser?
To cool down the gas that escape from the distillation flask and turn it back into liquid.
What is the purpose of paper chromatograpy?
To separate mixtures such as inks and food colourings
What is a chemical reaction?
In other word, how can I tell if there is a chemical rxn taking place?
A chemical reaction is a process that leads to the formation of new substances
The new substance is also known as products.
Give 2 examples of chemical reactions you have learnt in this chapter.
There are 4 examples.
- cooking of food
- burning of fuel
- decaying of food
- rusting of iron
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.
reactants: carbon dioxide, water
products: food, oxygen
A blue and red litmus paper is used on an acid.
What is the result of the test?
Blue litmus paper turns red.
Red litmus paper remains red.
A blue and red litmus paper is used on an alkali.
What is the result of the test?
Red litmus paper turns blue.
Blue litmus paper remains blue.
A blue and red litmus paper is used on a neutral solution.
What is the result of the test?
Red litmus paper remains red.
Blue litmus paper remains blue.
A universal indicator solution is used on an alkali.
What is the result of the test? Use the universal indicator chart to help you.
It can be either green, blue or purple.
The strength of the alkali determine the colour.
This is one of the reaction with acid:
acid + metal —> salt + ______________
Identify the missing product.
hydrogen gas
This is one of the reaction with acid:
acid + carbonate —> salt + ______________ + ________________
Identify the missing products.
carbon dioxide gas and water
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,
water
