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Chemistry, 7/e

Mass Relationships in Chemical Reactions

# Self Assessment A

 1 Determine the number of moles of aluminum in 0.2154 kg of Al. A) 1.297 x 1023 mol B) 5.811 x 103 mol C) 7.984 mol D) 0.1253 mol E) 7.984 x 10-3 mol 2 How many phosphorus atoms are there in 2.57 g of P? A) 4.79 x 1025 B) 1.55 x 1024 C) 5.00 x 1022 D) 8.30 x 10-2 E) 2.57 3 How many grams of acetylsalicylic acid (aspirin, C9H8 O4) are present in 1.32 x 10-2 mol of C9H8 O4? A) 1.32 x 10-2 g B) 2.38 g C) 180.2 g D) 7.33 x 10-5 g E) None of the above. 4 Calculate the percent composition by mass of nitrogen in ammonium nitrate (NH4 NO3). A) 0.175% B) 0.350% C) 17.5% D) 35.0% E) 42.5% 5 A compound with a percent composition by mass of 87.5% N and 12.5% H was recently discovered. What is the empirical formula of this compound? A) NH2 B) N2H3 C) NH D) N2H2 E) N2H 6 What is the coefficient for CO2 when the following chemical equation is properly balanced using the smallest set of whole numbers? C4H10 + O2 ----> CO2 + H2O A) 1 B) 4 C) 6 D) 8 E) 12 7 What mass of copper nitrate would be produced from the complete reaction of 45.6 g of copper, according to the chemical reaction shown below? Cu + 2 AgNO3 ----> Cu(NO3) 2 + 2 Ag A) 0.72 g B) 21.1 g C) 98.7 g D) 135 g E) 187 g 8 Calculate the number of moles of H2O formed when 0.200 mole of Ba(OH) 2 is treated with 0.500 mol of HClO3 according to the chemical reaction shown below. Ba(OH) 2 + 2 HClO3 ----> Ba(ClO3)2 + 2 H2O A) 1.00 mol B) 0.600 mol C) 0.500 mol D) 0.400 mol E) 0.200 mol 9 Ammonia is produced industrially from the reaction of nitrogen and hydrogen. Write the balanced chemical equation for this reaction, and determine the largest mass of NH3 that could be produced from the reaction of 105 g of N2 and 15.0 g of H2. A) 28.4 g B) 42.2 g C) 63.8 g D) 84.3 g E) 128 g