Question

@Somy How many liters of oxygen gas, at standard temperature and pressure, will react with 35.4 grams of calcium metal? Show all of the work used to solve this problem.

2 Ca + O2 yields 2 CaO

For this question would I use PV = nRT?

Answer 1

no this time you do not use it

Answer 2

find moles of calcium metal

Answer 3

0.8

Answer 4

there are 2 Ca

Answer 5

40.1* 2= your Mr for Ca

Answer 6

Oops, right. So like 2.26

Answer 7

Mr = 80.2
mass = 35.4

Answer 8

mole= mass/Mr
try again

Answer 9

0.44

Answer 10

thats right)

Answer 11

2 Ca + O2 yields 2 CaO

now ratio
whats the ratio between Ca and O2?

Answer 12

2:1?

Answer 13

good
so if
2- 0.44
1- ?

Answer 14

.22

Answer 15

thats right now u got moles of O2

Answer 16

there is a formula connecting Volume , standard temperature and pressure value, and moles

Answer 17

value of standard temperature and pressure is 22.4 if i remember correctly

Answer 18

check out your notes

Answer 19

Let me check real quick

Answer 20

yeah it's 22.4 as i thought http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html STP is http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html

Answer 21

This is what I have

Answer 22

oh its not about this the value is in Liters and it's known so u can straightaway use 22.4dm3

Answer 23

OH, okay lol.

Answer 24

\[Volume = mole \times 22.4 \]
do this and you'll get your answer :)

Answer 25

it's the formula for when you need to find volume or mole and you are given either one and the question is telling you that it's happening (reaction is happening) under standard temperature and pressure
so do not mix it up :)

Answer 26

V= .22 x 22.4?

Answer 27

yes :)

Answer 28

So it's 4.93

Answer 29

that's right) and the unit is dm3 or Liters

Answer 30

liters since it's asking for that right

Answer 31

yup) so u don't need to convert anything :D

Answer 32

Awesome! Can you help me with my last one?

Answer 33

lets see it :)

Answer 34

If 5.0 liters of carbon dioxide gas are produced by the reaction below at STP, how many liters of oxygen gas were used in the reaction?

2 CO (g) + O2 (g) yields 2 CO2 (g)

Answer 35

use volume formula :D

Answer 36

and find mole of CO2

Answer 37

V = 12 x 22.4?

Answer 38

nvm wait a sec lol

Answer 39

u are given volume of CO2 and u know STP so find mole

Answer 40

5.0 = .22 x 22.4 = 4.9

Answer 41

omg lol 0.22???? it's from ur previous question

Answer 42

Volume= mole * 22.4
mole= Volume/22.4 =5.0/22.4=

Answer 43

LOL im all over the place

Answer 44

Wait so Im confused now

Answer 45

what u don't get?