Question

Make the following conversions below.

A. 32.0g CH4 to moles (2.00 moles)
B. 8.76g of NaOH to moles (0.219 moles)
C. 27.00 moles H2O to grams (486.5 g)
D. 4.3 moles Ne to grams (87 g)
E. 0.78 moles Mg2O3 to formula units (4.70 x 10^23)
F. 155 g NH4OH to formula units (2.66 x 10^24)
G. 4.78 x 10^23 atoms Ag to moles (0.797 moles)
H. Determine the mass of one molecule of H2O (3.0 x 10^-23 g)

Answer 1

A. moles= mass/molar mass therefore the molar mass of CH4 is (12+1×4)=16

32.0÷16.0=2.00 moles

B. moles=mass/molar mass (molar mass of NaOH is 40) Na,23+ O,16+ H,1

8.76÷40=0.219moles

C.mass = moles ×molar mass

molar mass(H2(1×2=2+ O=16 ,16+2=18

27.00×18 =486 g

D. molar mass of Ne is 20.17g/mol so,to find it's mass we multiply the number of moles and the molar mass

4.3 ×20.17=86.731 rounded off to the nearest whole number is 87g

E.The Avogadro's constant 6.023×10^23 is equivalent to 1 mole

1 mole= 6.023×10^23

0.78=?

0.78×6.023×10^23=4.69794 ×10^23 , rounded off to the nearest whole number is 4.70 ×10^23

F.NH4OH molar mass=