Chemical Equations and Reactions

Question 1

Molecule

Answer 1

An aggregate of at least 2 atoms of a definite arrangement held together by chemical forces

• Diatomic: only 2 atoms
• Polyatomic: more than 2 atoms

Question 2

Molecular mass

Answer 2

Sum of atomic masses in a molecule e.g. H2O = 18

Question 3

Mole

Answer 3

Relates mass of a substance to a number of atoms/molecules present. A unit to count numbers of particles
1 mole = 6.022 x 1023

Question 4

Chemical reactions

Answer 4

A process in which a substance or substances is/are changed into one or more new substances. A chemical equation uses chemical symbols to show what happened during a chemical reaction.

Question 5

Molar mass

Answer 5

The mass in grams of 1 mole of molecules or 1 mole of atoms. E.g 1 mole of C=12grams

Question 6

Molecular formula

Answer 6

shows the exact no. of atoms of each element in a molecule C6 = 6 carbons

Question 7

How to balance chemical equations

Answer 7

1. 1 in front of most complicated molecule
   
   2. Leave oxygen last *
      Balance equation with smallest whole number

Question 8

solution

Answer 8

Homogeneous mixture of 2 or more substances can be formed in any state of matter that is they may be solid liquid or gas

Question 9

concentration

Answer 9

The amount of soluble present in a given amount of solvent, or a given amount of solution

Question 10

Dilute

Answer 10

Contains relatively little solute in a large quantity of solution

Question 11

Concentrated

Answer 11

Contains relatively large amount of solute in a given quantity of solution.

Question 12

Calculating the weight/volume%

Answer 12

Grams of solute/100ml of solution

Question 13

Isotonic

Answer 13

A solution that has the same concentration of solute as in our blood 0.9% ACL, 5%glucose

Question 14

Molarity

Answer 14

no moles of a solute per litre of a solution

Question 15

Osmosis

Answer 15

Movement of water across a semi permeable membrane

Question 16

Hypotonic

Answer 16

contains fewer solutes (such as salt and other electrolytes) than is found in normal cells and blood

Question 17

Hypertonic

Answer 17

contains more solutes (such as salt and other electrolytes) than is found in normal cells and blood