Part A Calculate the percentage by mass of the indicated element in the following compounds. Hydrogen in ammonium sulfate, (NH4)2SO4, You may want to reference (Pages 91 - 92) Section 3.3 while completing this problem. a substance used as a nitrogen fertilizer Express your answer using two significant figures.

Please put the correct number of significant figures

Complete the following calculations. Mass calculations Mass of watch glass and evaporating dish: Mass of watch glass, evaporating dish, and Mg ribbon: Calculate the mass of Mg (g) Mass of watch glass, evaporating dish, and reacted Mg after cooling: Calculate the mass of the product (g) 62.254 g 62.534 g 63.375 g

Acid rain is caused in part by burning coal that contains sulfur impurities. The sulfur is converted first to SO2, which reacts with oxygen and atmospheric moisture to produce sulfuric acid, H2SO4. If a particular coal contains 1.90% sulfur (by mass), calculate the mass of sulfuric acid produced by burning a metric ton (1000 kg) of the coal.

An amount (in grams) of nitrogen gas is reacted with excess hydrogen, according to the balanced reaction shown below.  If 104 g of NH3 is recovered, giving a percent yield of 42%, what was the mass of the nitrogen (in grams) that reacted?   N2 (g) + 3 H2 (g) -->  2 NH3 (g)   Report your answer as an integer, that is as a number with zero decimal places, and with no units.  Do NOT use scientific notation.

A pure sample of an organic molecule has the formula CxHyOz. If x = 11, y = 13, and z = 2. Calculate the percent by mass of oxygen in the formula. Round your result to the nearest tenth number; do not enter a % sign in your answer.

A Freon leak in the air conditioning system of an older car releases 28 g of CF2C12 per month. Part A What mass of chlorine is emitted into the atmosphere each year by this car? Express your answer using two significant figures.

A chemist needs 32.0 g of phenol, C6H5OH, for an experiment. How many moles of phenol is this?   Explain how to find the molar mass of the compound. Explain how many significant figures your answer needs to have. The numerical answer

Starting with 8.39 X 1018 grams of HCIO4, how many molecules of Cl207 can you make? 12 HCIO, + P,O10 = 4 H3 PO4 + 6 Cl207 Round your answer to 2 decimal places and, if needed, enter scientific notation like this 6.02e23 (would mean 6.02 x 1023.)