Question

PLEASE HELP!
How many liters of a 2.25 molar hydrobromic acid (HBr) solution would be needed to react completely with 100.0 grams of calcium metal?

Ca (s) + 2HBr (aq) CaBr2 (aq) + H2 (g)

Answer 1

I got 2.00? the answer choices are

1.11 liters

2.22 liters

2.81 liters

22.5 liters

Answer 2

convert 100 g of calcium to moles

then use the concentration of the HBr in the molarity equation (don't forget to take the stoichiometric coefficient into account)

Answer 3

so it would be:

100g Ca x 1 mol Ca/ 40.1 g Ca x 2 mol HBr/1 mol Ca x 1 L HCl solution/ 2.5 mol HBr

Answer 4

nope, do one step at a time..

molarity of Hbr = the moles of calciumx2/L

you're solving for liters

Answer 5

wait you're actually right

Answer 6

but my answer is 2.00???

Answer 7

but it's 2.25 M not 2.5

Answer 8

oh...wow:/

Answer 9

lol

Answer 10

will you help me with one more?

Answer 11

sure

Answer 12

The density of an unknown gas is found to be 3.44 g/L at standard temperature and pressure (STP). What is the molar mass of this gas?

Answer 13

use the ideal gas law and manipulate it to solve for molar mass

Answer 14

how do I do that..?

Answer 15

algebra and substitution

Answer 16

try it, if you can't do it ill show you

Answer 17

well idk how to start it

Answer 18

ik ideal gas law is Pv=nRT

Answer 19

PV=nRT

moles definition: n=m/M

PV=mRT/M

Answer 20

3.44g/L x 0.0821L-atm/mole-K x 273K / 1atm = molar mass = 77.1g/mole?

Answer 21

looks right

Answer 22

ok thank you!!

Answer 23

no prob!