Chemistry

Question 1

What is the definition of a chemical element?

Answer 1

A substance made up of just one type of atom

Question 2

Explain the difference between atomic mass and atomic number for an element

Answer 2

The number of protons in an atom is called the atomic number and the number of protons plus neurons is the atomic mass

Question 3

The three types of elements on the periodic table are?

Answer 3

Non-metals, metals and metalloids

Question 4

What are the characteristics of a metal?

Answer 4

lustrous, malleable, ductile, dense, thermal conductors, electrical conductors and solid at room temp

Question 5

What are the characteristics of a non-metal?

Answer 5

low melting point, poor conductors of heat and electricity,, brittle and dull

Question 6

What are the characteristics of a metalloid?

Answer 6

semi-conductors

Question 7

why do metals form positive ions in terms of electron configuration

Answer 7

because in their outer shell of outer electrons there is always less than 4 electron, this means that it is easier to lose electrons than gain electrons

Question 8

negatively charged ions are called what?

Answer 8

anion

Question 9

positively charged ions are called?

Answer 9

cation

Question 10

In the periodic table, the vertical columns are called what? and the horizontal rows are called what?

Answer 10

Vertical columns are called groups and horizontal rows are called periods

Question 11

What is an isotope?

Answer 11

Isotopes are atoms that have the same number of protons but a different number of neutrons, they are different ‘versions’ of the same element

Question 12

What is a half life?

Answer 12

The half-life of a radioisotope is the time is takes for half the nuclei to decay

Question 13

What is the equation for photosynthesis?

Answer 13

sunlight
carbon dioxide + water ————-> glucose + oxygen
chlorophyll
sunlight
6CO2 + 6H2O ————> C6H12 + 6O2
chlorophyll

Question 14

What is incomplete combustion and complete combustion?

Answer 14

Incomplete combustion occurs when the oxygen supply is restricted in some way, so the other reactions occur instead - it is exothermic but does not release as much heat or light energy as complete combustion.

Complete combustion occurs whenever something reacts with oxygen gas (O2), burning it exploding as it does so.

Question 15

What do the following give?
An acid plus a base gives _______________
An acid plus a metal gives ______________
An acid plus a carbonate gives ____________

Answer 15

An acid plus a base gives neutralisation, it gives a salt + water.
An acid plus a metal gives corrosion, it gives a salt + hydrogen gas
An acid plus a carbonate gives a salt + water + carbon dioxide

Question 16

What is the Law of Conservation of Mass for Chemical Reactions?

Answer 16

Matter cannot be created or destroyed. The mass of reactions is equal to mass of products