Question

How many grams of sodium metal are needed to react completely with 25.8 liters of chlorine gas at 293 Kelvin and 1.30 atmospheres?

Answer 1

can people tell me how 2 get moles?

Answer 2

@iPwnBunnies @ParthKohli

Answer 3

@aaronq

Answer 4

@AccessDenied

Answer 5

@jigglypuff314

Answer 6

can you tell me how to get moles?

Answer 7

use the ideal gas equation, PV=nRT, to get moles, n.

Answer 8

so?

Answer 9

how do i do it?

Answer 10

n=PV*RT?

Answer 11

or divide...;(

Answer 12

nope, divide n=PV/RT

Answer 13

oh

Answer 14

P=pressure, V=volume, and R=constant, and T=temp. right?

Answer 15

correct, T needs to be in Kelvin, btw.

Answer 16

oh?

Answer 17

n=1.3 x 25.8/0.0821 x 293?

Answer 18

is it this?

Answer 19

yeah (i just noticed the temp is already given in Kelvin lol)

Answer 20

lol

Answer 21

so is that correct?

Answer 22

Yeah, now to find the grams of sodium, you need to find the moles of sodium first, then convert.

Answer 23

1.294g/mol.

Answer 24

whoops, 1.394

Answer 25

right?

Answer 26

yeah, but the units aren't "g/mol", it's just moles

Answer 27

oh

Answer 28

so i just do the thing, except i add n instead of =n right?

Answer 29

im not sure i follow

Answer 30

?

Answer 31

what do i do after i find mole?

Answer 32

you need to use the molar ratio between them, so write and balance the chemical equation for the process

Answer 33

i know the balanced equation 2 Na (s) + Cl2 (g) → 2 NaCl (s)

Answer 34

i think its that, it was already given

Answer 35

yeah that's it.

so now, make a ratio of the moles with the coefficients:

\(\dfrac{n_{Na}}{2}=\dfrac{n_{Cl_2}}{1}\)

plug in moles of what you know, then solve

Answer 36

ok...

Answer 37

ummm, 1.394Na/2=1.394Cl^2/1?

Answer 38

which is 0.697=1.394

Answer 39

you only know the moles of \(Cl_2\), right? (you found this above)

this \(n_{Cl_2}\) is just a symbol for that.

so it's \(\dfrac{n_{Na}}{2}=\dfrac{1.394}{1}\rightarrow n_{Na}=\dfrac{1.394*2}{1}\)

Answer 40

yeah

Answer 41

oh

Answer 42

2.788Na

Answer 43

yeah so that's moles, 2.788 moles of sodium metal

now convert the moles to grams, use \(n=\dfrac{m}{M}\)

Answer 44

ok

Answer 45

1.394=whats m/M?

Answer 46

m = mass in grams (what you're looking for)
M= molar mass (of sodium)

Answer 47

ok

Answer 48

1.394=m/2.788

Answer 49

m=2.788 x 1.394?

Answer 50

m=3.89

Answer 51

the molar mass of sodium is 22.9898 g/mol

Answer 52

you can find this on a periodic table

Answer 53

oh

Answer 54

the atomic number?

Answer 55

well, the number below

Answer 56

nope, the atomic number is only the number of protons

Answer 57

yeah, it's called atomic mass (or molar mass because it's the mass of 1 mole of that substance)

Answer 58

ok, so now

Answer 59

1.395=22.989/2.788

Answer 60

hm you're confusing the variables.

n=moles = 2.788 moles
m=mass (in grams) = x
M= molar mass = 22.9898 g/mol


the formula is: \(n=\dfrac{m}{M}\)

Answer 61

ohhhh

Answer 62

2.788=x/22.9898

Answer 63

so, x=2.788 x 22.9898?

Answer 64

yes

Answer 65

x=64.1

Answer 66

\(\checkmark \)

Answer 67

dont forget the units

Answer 68

yay! 64.1g/mol

Answer 69

nope, just grams. remember this is the mass, not the molar mass

Answer 70

kk