How would you the mass in grams of 4.52 xx10^-34.52×103 "C"_20"H"_42"C20H42? Use the molar masses: C = 12.0 g/mole; H = 1.0 g/mol.

2 Answers
Dec 23, 2017

Take the product..."molar quantity"xx"molar mass"molar quantity×molar mass; I gets a tad over 1*g1g...

Explanation:

You got the molar quantity...4.52xx10^-3*mol4.52×103mol...(you have not specified the units in your question, but I assume that these units pertain); and multiply these units by the molar mass...

4.52xx10^-3*molxx(20xx12_("atomic mass of carbon")+42xx1_("atomic mass of hydrogen"))*g*mol^-1=??*g4.52×103mol×(20×12atomic mass of carbon+42×1atomic mass of hydrogen)gmol1=??g

Dec 23, 2017

The mass of 4.52xx"10"^(-3) "mol C"_20"H"_42"4.52×103mol C20H42 is "1.27 g"1.27 g.

Explanation:

If the mass of 4.52xx"10"^(-3) "mol C"_20"H"_42"4.52×103mol C20H42 is what you are looking for:

Determine the molar mass of "C"_20"H"_42"C20H42.

"Molar mass"Molar masscolor(white)(.). "C"_20"H"_42: C20H42:(20xx"12.0 g/mol C")+(42xx"1.0 g/mol H")="282 g/mol C"_20"H"_42"(20×12.0 g/mol C)+(42×1.0 g/mol H)=282 g/mol C20H42

Mass of 4.52xx"10"^(-3) "mol C"_20"H"_42"4.52×103mol C20H42

Multiply mol "C"_20"H"_42"C20H42 by its molar mass.

4.52xx"10"^(-3) color(red)cancel(color(black)("mol C"_20"H"_42))xx(282"g C"_20"H"_42)/(1color(red)cancel(color(black)("mol C"_20"H"_42)))="1.27 g C"_20"H"_42" rounded to three significant figures