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Flashcards in Relative Formula Mass Deck (19)
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1
Q

What is another way of saying relative atomic mass?

A

Ar.

2
Q

Relative atomic mass is usually the same as what?

A

As the mass number of the element.

3
Q

Relative atomic mass is what?

A

How heavy different atoms are compared with the mass of an atom of carbon-12.

4
Q

Carbon-12 has a relative atomic mass of what?

A

Exactly 12.

5
Q

Elements in the periodic table all have what?

A

2 numbers.

6
Q

The smaller number is called what?

A

Atomic number.

7
Q

What does the atomic number tell us?

A

How many protons it has.

8
Q

The bigger number is called what?

A

The mass number.

Relative atomic mass.

9
Q

The relative atomic mass is found where?

A

The number on top of the element

10
Q

What happens when an element has more than one stable isotope?

A

The relative atomic mass is an average value of all the different isotopes.

11
Q

How else is relative formula mass written as?

A

Mr.

12
Q

If an example of a compound which has a relative formula mass?

A

MgCl2.

13
Q

A compound with a relative formula mass means what has happened?

A

All the relative atomic masses added together.

14
Q

What would MgCl2 relative atomic mass be?

A

24 + (35.5 x 2) = 95.

15
Q

Relative formula mass means…

A

Add up all the relative atomic masses.

16
Q

One mole of a substance is equal to what?

A

Its Mr, in grams.

17
Q

The relative formula mass of a substance is known as what?

A

One mole of that substance.

18
Q

What formula do you use to find the number of moles?

A

Mass in g divided by Mr.

19
Q

How many moles are there in 42g of carbon?

A

42g divided by 12 = 3.5 moles.