What is the mass of 3 moles of #"C"_2"H"_2# ?

3 Answers

Answer:

#"78 g"#

Explanation:

Every mole of #"C"_2"H"_2# (acetylene) has a mass of #"26.04 g"#, i.e. acetylene has a molar mass of #"26.04 g/mol"#.

Thus,

#"26.04 g/mol " * " 3 mol"#

gives you the mass of #3# moles, #"78 g"#

Feb 26, 2018

Molar mass of #C_2H_2 => 26g#, that's the mass of 1 mole.

Therefore, mass of 3 moles of #C_2H_2# would be #26 xx 3 = color(red)(78g#

Feb 27, 2018

Answer:

#78 \ "g"#

Explanation:

Acetylene #(C_2H_2)# has a molar mass of #26.04 \ "g/mol"#.

To find out the mass of moles, we have to multiply the number of moles by the molar mass of the substance, i.e. we can form an equation like this:

#"mass"="moles"*"molar mass"#

So, the mass of three moles of acetylene is

#"mass"_(C_2H_2)=3color(red)cancelcolor(black)"mol"*(26.04 \ "g")/(color(red)cancelcolor(black)"mol")=78.12 \ "g"#

Now, we can round off to the nearest whole number to make the answer more reasonable, so it'll be

#78.12 \ "g"~~78 \ "g"#