Please help I don't understand this at all :(

for A it is 217,269 litres
for B it is 9.69g
for C it is 106.624L

Explanation:

A) you are given the number of moles, from the given formula you can get the molar mass which is 12.00g/mol + 16 g/mol =28 g/mol. using the formula n=m/Mr rearrange the formula and make m subject, you thn have m=nMr therefore 7.60x 1021 mol x 28g/mol= m

m = 217268.8 g, you will notice that mol cancel out each other leaving you with g.

now convert g to litres

1 litre is equal to 1000 grams therefore

217268.8g x 1l/1000g = 217,269 litres

B) 9.69g

Explanation:

To obtain the desired result, first let us calculate the number of mole of N2 in 7.744L of the gas.

1mole of a gas occupies 22.4L at stp.

Therefore, Xmol of nitrogen gas(N2) will occupy 7.744L i.e

Xmol of N2 = 7.744/22.4 = 0.346 mole

Now let us convert 0.346 mole of N2 to gram in order to obtain the desired result. This is illustrated below:

Molar Mass of N2 = 2x14 = 28g/mol

Number of mole N2 = 0.346 mole

Mass of N2 =?

Mass = number of mole x molar Mass

Mass of N2 = 0.346 x 28

Mass of N2 = 9.69g

Therefore, 7.744L of N2 contains 9.69g of N2

C) The volume of carbon dioxide gas at STP for given amount is 106.624 L

Explanation:

We are given:

Moles of carbon dioxide = 4.76 moles

At STP:

1 mole of a gas occupies a volume of 22.4 Liters

So, for 4.76 moles of carbon dioxide gas will occupy a volume of = \frac{22.4L}{1mol\times 4.76mol=106.624L

Hence, the volume of carbon dioxide gas at STP for given amount is 106.624L

indium, and thallium have three electrons i think

the answer is b & c i believe : )