1.6 QUANTIFYING ELEMENTS & COMPOUNDS

Question 1

Are zeros between other non zero digits significant?

Answer 1

YES. zeros in between other non zero digits are always significant

Question 2

Do we use the relative atomic mass or the atomic number to measure mole?

Answer 2

The relative atomic mass (u)

Question 3

Are trailing zeros at the end of a number that contains a written deicimal point significant?

2.035264000

Answer 3

YES!

0’s at the end of a number WITH a written decimal point are ALWAYS significant

Question 4

For example: sodium (Na) has a mass of 22.99u, which means one mole of Na is?

Answer 4

One mole of sodium is 22.99g

22.99g = 6.02 x 10^23

Question 5

Write the scientific notation for:

0.0000516

Answer 5

5.16 x 10^-5

Question 6

What does n in M x 10^n represent?

Answer 6

n is the number of decimal places to be moved and the direction in which it moves.

Question 7

Why do we use moles?

Answer 7

Used to measure compounds and elements so we can get the exact amount of particles involved in chemical reactions.

Also used because particles are very small and need a large number to represent it accurately.

Question 8

What is molar mass?

Answer 8

Molar mass is defined as the mass in grams of one mole of a substance. The units of molar mass are grams per mole, abbreviated as g/mol.

Question 9

What does a positive ^n indicate for a number in standard form?

Answer 9

This indicates that this is a large number

4.35 x 10^16 = 43 500 000 000 000 000

Question 10

What are base units?

Answer 10

m/s/mol

Question 11

What is the particle entitiy for ionic compounds?

Answer 11

Formula Units

Question 12

What is the pre-fix for 10^2

Answer 12

hecto

Question 13

What is the formula for scientific notation?

Answer 13

M x 10^n

Question 14

Are zeros at the front of a number significant?

0000056983.254

Answer 14

NO. zeros at the front of a number are never significant

Question 15

Equation for:

Number of Particles =

Answer 15

Number of particles = number of moles × Avogadro’s number

or

N = n × NA

Question 16

What does a negative ^n indicate in standard form?

Answer 16

It indicates that the number is small.

0.00000632 = 6.32 x 10^-6

Question 17

What is the prefix for 1 x 10^-9?

Answer 17

nano

Question 18

What are the rules of significant digits?

Answer 18

Question 19

What is Avogadro’s Number?

Answer 19

Avogadro’s Number is the name of a measurement used to represent 6.02 x 10^23 of something. It is used to show how large of an amount there is.

Question 20

What is the symbol for mole?

Answer 20

(n), not exponent ^n in scientific notation

Question 21

What are the entities of a molecular compound?

Answer 21

molecules

Question 22

What direction does the decimal in a negative n move?

Answer 22

The decimal moves to the left, making the number smaller

5.648 x 10^-8 = 0.00000005648

Question 23

What is Avogadro’s Number equal to?

Answer 23

Avogadro’s Number is equal to one mole.

For example: one mole of iron is 6.02 x 10^23 of iron atoms.

Question 24

What is a significant figure/digit?

Answer 24

A sig figure/digit is something that is actually measured.

Question 25

When taking the atomic relative mass to measure molar mass, how many digit places do we round to?

Answer 25

the nearest hundredth. For example Oxygen has mass of 15.99amu This becomes 16.00g/mol

Question 26

What is the difference between **molecular mass** and **molar mass**?

Answer 26

**Molecular** weight is the **mass of a molecule of a substance**. It can also be called molecular mass. ... **Molar** mass is the **mass of one mole of a substance**. Molar mass is reported in grams per mole or **g/mol**

Question 27

What direction does the decimal move in a positive n?

Answer 27

The decimal moves to the right. **5.436 x 10^8 = 543 600 000.**

Question 28

What is the particle entity for elements?

Answer 28

atoms.

Question 29

In Scientific Notation, what numbers does M in M x 10^n have to be between?

Answer 29

where 1 lesser or equal to M lesser than 10.

Question 30

What is the name of the atomic amount used to measure chemical quantities?

Answer 30

a mole

Question 31

What is molar mass of a molecule?

Answer 31

Sum of the individual molar masses of the atoms in the mole. **For Example: one H2O** 2 Hydrogen: 2 x 1.01u = 2.02u 1 oxygen: 1 x 16.00 = 16.00u 2.02u + 16.00u = 18.02g/mol

Question 32

Write the scientific notation for: ## Footnote **0.698534 x 10^9**

Answer 32

**698 534 000**

Question 33

What equation do you use to find the Molar Mass?

Answer 33

**M = m/n** molar mass (g/mol) = mass (g) / number of mols (mol)