Question

1)

A)
How many moles of Br are there in a sample of Br that contains 3.15×10²⁴atoms?
moles

B)

How many Ba atoms are there in 4.39 moles of Ba?

atoms

2)

How many moles of Br are there in 63.0grams of Br?

moles

How many grams of Ba are there in 4.39moles of Ba?

grams

3)

How many Ca atoms are there in a 63.0gram sample of Ca ?
atoms

How many grams of Rb are there in a sample of Rb that contains 1.03×10²⁴atoms? grams

4)

Complete the table below for calculating the molar mass of the compound carbon monoxide.

...

Molar mass

...

Moles

...

Mass in one mole of carbon monoxide

C

g/mol

mol

g

O

g/mol

mol

g

Molar mass carbon monoxide =   g/mol

B)

Complete the table below for calculating the molar mass of the ionic compound potassium oxide .

Formula

...

Molar mass

...

Number of ions

...

Mass of ion in one mole of potassium oxide

Cation

K⁺

g/mol

mol

g

Anion

O^2-

g/mol

mol

g

Molar mass potassium oxide =   g/mol

5)

1. How many GRAMS of carbon are present in 3.12 moles of carbon monoxide ?   grams.

are present in 4.15moles of this compound ? grams.


2. How many MOLES of aluminum chloride are present in 4.50grams of this compound ? moles.


2. How many MOLES of oxygen are present in 1.29 grams of carbon monoxide ?   moles.

Answer 1

A)

How many moles of Br are there in a sample of Br that contains 3.15×1024atoms?

1 mol = 6.022*10^23 atoms

then

total mol = (3.15*10^24)/6.022*10^23 = 5.23082 mol of Br

B)

How many Ba atoms are there in 4.39 moles of Ba?

1 mol = 6.022*10^23

4.39 mol = 4.39*6.022*10^23 = 2.6436*10^24 atos of Ba

2)

How many moles of Br are there in 63.0grams of Br?

MW of Br = 79.904

mol = mass/MW = 63/79.904 = 0.78844 mol of Br

b)

How many grams of Ba are there in 4.39moles of Ba?
MW = 137.327

mass = mol*MW = 4.39*137.327 = 602.86553 g of Ba

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