Question

boop

Answer 1

A sample of neon has a volume of 75.8 L at STP. How many moles are present?

Answer 2

@Vocaloid

Answer 3

1 mol = 22.4L

so divide 75.8 L by 22.4 L to convert to moles

Answer 4

33.83?

Answer 5

shift a decimal place over

3.38moles --> ans

Answer 6

What is the mass in grams of a 8.4 mole sample of iron?

Answer 7

to go from moles to mass, multiply moles by the molar mass

so 8.4 * 55.8 g/mol -->

Answer 8

468.72

Answer 9

good

only 2 sig figs so I would round to 470g

Answer 10

Convert 0.45 g of sodium hydroxide, NaOH to moles

Answer 11

going from gram to moles is the opposite of what we did before, so divide by the molar mass

0.45g/39.997 -->

Answer 12

0.011

Answer 13

good, 0.011moles

Answer 14

What is the mass in grams of 0.94 moles of sodium bicarbonate, NaHCO3?

Answer 15

similar as before, moles * molar mass = total mass

0.94 * 84.007 -->

Answer 16

78.96

Answer 17

good but only 2 sig figs so 79g

Answer 18

A gold coin contains 3.47 × 1023 gold atoms. What is the mass of the coin in grams?

Answer 19

atoms -> moles -> grams

divide by Avogadro's number (6.022e23) to get to moles
then multiply by the molar mass of gold

for future reference you can find molar masses on ptable.com or google

Answer 20

so whats the equation? 3.47 x 1023 / avg #?

Answer 21

yes, that's the first step, then the second step is to multiply by the molar mass of gold

Answer 22

(3.47 x 10^23)/(6.022*10^23) * molar mass of gold (you can get the molar mass from the periodic table, get into the habit of reading the ptable)

Answer 23

196.96?

Answer 24

that equals 113.49

Answer 25

good, and w/ sig figs that's 113g of gold --> ans

Answer 26

One component of smog is nitrogen monoxide, NO. A car produces about 8 g of this gas per day. What is the volume at STP?

Answer 27

grams -> moles -> liters

to go from grams to moles, divide by the molar mass of NO (to find this, add up the Molar masses of oxygen + nitrogen)

then multiply by 22.4L

Answer 28

equation?

Answer 29

you are given grams

divide by the molar mass

multiply by 22.4L

Answer 30

so 8/30.01 x 22.4L?

Answer 31

yup just like that

Answer 32

5.97

Answer 33

good, and since we only have 1 sig fig we round up to 6

Answer 34

okay! thanks!