Module 2, Atoms And Moles And Formulas And Equations

Question 1

Isoelectronic

Answer 1

When ions of different elements have same number of electrons

Question 2

What do the peaks represent in mass spectrometry

Answer 2

Different isotopes

Question 3

What is avogadro’s constant

Answer 3

6.022x10^23

Question 4

What is the equation for number of particles

Answer 4

N(moles) x Na(avogadro’s constant)

Question 5

What is the equation for number of moles

Answer 5

Mass(g)/mr

Question 6

Empirical formula definition

Answer 6

Simplest whole number of ratio. Of atoms/ions of an element in a compound.

Question 7

Relative atomic mass

Answer 7

Ratio of average mass of atoms that is constant which is one twelfth the mass of a carbon-12 atom

Question 8

Stoichemitry

Answer 8

Relationship between substances in a equation

Question 9

What assumptions are made when reacting masses

Answer 9

100% transformation, excess hydrogen

Question 10

Limiting reactant

Answer 10

Is one used up

Question 11

Excess reactant

Answer 11

One that has left over moles after reacting

Question 12

1 What did dalton describe the model

Answer 12

Solid spheres, different spheres made of different elements

Question 13

2 describe Thomsons findings

Answer 13

Measurements of charge and mass showed atom must contain negative charged particles, electrons. Plum pudding model, positive charged sphere with negative electrons embedded.

Question 14

3 describe Rutherford findings

Answer 14

Worked with Geiger and marsden, gold foil experiment, fired alpha particles at thin sheet of gold. Expected most Alpha particle to be deflected slightly most went straight through A small number deflected backwards which showed the plum pudding model couldn’t be right came up with the nuclear model where there is a tiny positive charge nucleus at the centre surrounded by cloud of negative electrons where the mass concentrated in the centre and the atom is empty Space. Discovered protons

Question 15

4 Bohr findings

Answer 15

Electrons existed in fixed orbit is known as shells and had a fixed energy. He came up with the bohr model which is similar to the one now.

Question 16

Relative isotopic mass

Answer 16

Mass of an atom of an isotope of an element compared to 1/12 of mass of carbon-12

Question 17

Relative formula mass

Answer 17

Average mass of a formula unit, compared to 1/12th of the mass of a carbon-12

Question 18

Work out ionic equation

Answer 18

Write in ions form, cross out ions that appear on both sides, check charges balance, balance equation, write into constituent ions(eg 2Na3= 6Na), cross out bits on both side

Question 19

What is the equation for working out number of moles assuming gases at RTP

Answer 19

Number of moles= volume(dm3)/24