What is the empirical formula for a compound that contains 80% carbon and 20% hydrogen by mass

Tin has ten stable isotopes. the heaviest, 124sn, makes up 5.80% of naturally occuring tin atoms. how many atoms of 124sn are present in 82.0 g of naturally occurring tin? what is the total mass of the 124sn atoms in this sample?

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy

How many liters of 3.0 m naoh solution will react with 0.60 liters of 4.0 m h2so4? h2so4 + naoh → na2so4 + h2o 1.2 l 1.6 l 2.4 l 2.8 l