Relative Molecular Mass

Presentation

•

Chemistry

•

1st - 10th Grade

•

Hard

Joseph Anderson

FREE Resource

3 Slides • 31 Questions

Chemistry Topic 3 Recap

Multiple Choice

Each element is defined by its

Electron number

Isotopes number

Neutron number

Proton number (atomic number)

Multiple Choice

The relative atomic mass is the average mass of an atom compared to

the mass of a carbon-12 atom.

1/12 the mass of a carbon-12 atom

the mass of a hydrogen atom

1/12 the mass of a hydrogen atom

Multiple Choice

What is the atomic mass of magnesium?

Multiple Choice

What is the relative atomic mass (A_r) of Carbon?

Multiple Choice

What is the relative atomic mass (A_r) of Chlorine (Cl)?

35.5

18.5

0.5

Multiple Choice

What is the relative atomic mass (A_r) of Xenon (Xe)?

131

132

Fill in the Blanks

Which element has a relative atomic mass of 14?

Type answer...

CO₂

The little number next to the element tells us the number of atoms.

If there is no number this means there is 1 atom of that element.

How many atoms of Oxygen (O) are there in CO₂?

How many atoms of Carbon (C) are there in CO₂?

Multiple Select

In Sulfur hexafluoride (SF₆), how many atoms of Sulfur are there?

Multiple Select

In Sulfur hexafluoride (SF₆), how many atoms of Fluorine are there?

Multiple Choice

The relative molecular mass of a compound is equal to the sum of all its atoms'...

Atomic masses

Atomic numbers

Oxidation numbers

Outer shell electrons

Multiple Choice

Fluorine, F has a relative atomic mass (Ar) of 19. What is the relative molecular mass (Mr) of fluorine gas, F₂?

Multiple Choice

What is the relative molecular mass (M_r) of Hydrochloric Acid (HCl)?

Ar of H = 1, Ar of Cl = 35.5

34.5

36.5

35.1

To calculate Formula Mass

Find the relative atomic mass of each element
Count up how many atoms of each element and multiply this by the relative atomic mass of each one.
Add up the total numbers

Fill in the Blanks

What is the relative formula mass of CH₄?

Relative atomic mass (Ar) of C = 12 , Ar of H = 1

1) Count up the Carbon (C) and Hydrogen (H) atoms in CH₄.

2) Next we can multiply the number of atoms by the relative atomic mass (Ar) of each element

So: Relative Formula mass (Mr) = ( _ x 12) + (4 x 1)

What number goes in the blank space?

Type answer...

Fill in the Blanks

What is the relative formula mass of CH₄?

Ar of C= 12, Ar of H = 1

Relative Formula mass (Mr) = (1 x 12) + (4 x 1)

What do you get when you do this calculation?

Type answer...

Multiple Choice

What is the relative formula mass of carbon monoxide (CO)

Ar of C = 12 , Ar of O = 16

(No little number means one atom of Carbon and one atom of oxygen per molecule.)

Formula mass = (1 x 12) + (1 x 16) = ....

Multiple Choice

What is the relative formula mass of Sodium Hydroxide NaOH?

Ar of Na = 23, Ar of H =1 , Ar of O = 16

Relative Formula Mass = (1 x 23) + (1 x 16) + (1 x 1) = ...

This give us...?

Fill in the Blanks

Calculate the relative formula mass of

Carbon Dioxide, CO₂

Ar of O = 16 ; C = 12

Relative Formula mass = (1 x 12) + ( _ x 16)

What is the missing number?

Type answer...

Fill in the Blanks

Calculate the relative formula mass of Carbon Dioxide, CO₂

Ar of O = 16 ; C = 12

Relative Formula mass = (1 x 12) + ( 2 x 16)

What does this give you in total?

Type answer...

Fill in the Blanks

Calculate the relative formula mass of Ammonia, NH₃?

Ar of N = 14 ; H = 1

-> Relative Formula mass = (1 x 14) + (3 x _ ) =

What is the missing number?

Type answer...

Fill in the Blanks

Calculate the relative formula mass of Ammonia, NH₃?

Ar of N = 14 ; H = 1

-> Relative Formula mass = (1 x 14) + (3 x 1) =

What is the answer for the relative formula mass then?

Type answer...

Fill in the Blanks

Calculate the relative formula mass of Sodium Chloride, NaCl?

Ar of Na = 23 ; Cl = 35.5