Chemistry

Percentage Composition

100

A compound is found to contain 36.5% Na, 25.4 S, and 38.1% O. Find its empirical formula

Na₂SO₃

200

Find the empirical formula of a compound that is 53.7% iron and 46.3% sulfur.

Fe₂S₃

300

Analysis of a sample of a compound indicates that is has 1.04 g K, 0.70 g Cr, and 0.86 g O. What is its empirical formula?

K₂CrO₄

400

If 4.04 g of nitrogen combines with 11.46 g of oxygen to produce a compound with a molar mass of 216.0g, what is the molecular formula of this compound?

N₄O₁₀

500

The molar mass of a compound is 92 g.  Analysis of the sample indicates that it contains 0.606 g N and 1.390 g O.  Find the compound’s molecular formula

N₂O₄

Percentage Composition pt2

100

Find the empirical formula for 66.4% Cu, 33.6% S

CuS

200

Find the empirical formula for 62.6% Ca, 37.4% C

CaC₂

300

Find the empirical formula for 36.8% N, 63.2% O

N₂O₃

400

Find the empirical formula for 1.90% H, 67.6% Cl, 30.5% O

HClO

500

Find the empirical formula for 60% C, 13.3% H, 26.7% O

C₃₀H₇₉O₁₀

Balancing equations

100

___ H₃PO₄ + ___ KOH --> ___ K₃PO₄ + ___ H₂O

 1 H₃PO₄ +  3 KOH --> 1 K₃PO₄ + 3 H₂O

200

___ Rb + ___ S₈ ---> ___ Rb₂S

16 Rb +1 S₈ ---> 8 Rb₂S

300

___ Ca₃(PO₄)₂ + ___ SiO₂ + ___ C ---> ___ CaSiO₃ + ___ CO + ___ P

1 Ca₃(PO₄)₂ + 3 SiO₂ + 5 C ---> 3 CaSiO₃ + 5 CO + 2 P

400

___ Al + ___ S₈ ---> ___ Al₂S₃

16 Al + 3 S₈ ---> 8 Al₂S₃

500

___ CH₃CH₂CH₂CH₃ + ___ O₂ ---> ___ CO₂ + ___ H₂O

2 CH₃CH₂CH₂CH₃ + 13 O₂ ---> 8 CO₂ + 10 H₂O

Mole Conversion

100

How many moles are in 1.20x10²⁵ atoms of phosphorous

58.25

200

How many atoms are in .75 moles of zinc

4.151e23

300

How many molecules are in .4 moles of N₂O₅

2.408e²³

400

Find the grams in 1.26 x 10^-4 mol of HC₂H₃O₂

0.00717

500

What is the volume of 0.05 mol of neon gas at STP

1.12

Mole Conversion pt 2

100

How many moles of magnesium is 3.01 X 10²² atoms of magnesium

.05 moles

200

How many molecules are there in 4.00 moles of C₆H₁₂O₆

2.41 X 10²⁴

300

How many moles are in 28grams of CO₂

.636moles

400

Find the mass in 2.6 mol of lithium bromide

226.044

500

Determine the volume in liters occupied by .03 moles of a gas at STP

.672 liters