Chapter 6 HW
The number of grams in 7.00 moles of N2 is
196 (NOTE: N: 2 x 14.007= 28.01 28.01 x 7.00= 196.07 ==> 196)
The active ingredient in many antacid tablets is calcium carbonate, CaCO3. How many moles of calcium carbonate are contained in a tablet weighing 550. mg?
5.51 × 10^-3
What mass of PCl5 will be produced from the given masses of both reactants? Express your answer to three significant figures and include the appropriate units.
63.5 g (.305 g x 208.22= 63.507 ==> 63.5 g)
The combustion of propane gas (C3H8) is used to fuel barbeque grills. In order to produce 5.65 moles of water how many moles of oxygen gas are needed? C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l)
7.06 mol
In a reaction to produce ammonia, the theoretical yield is 420.g. What is the percent yield if the actual yield is 350.g?
83.3% (NOTE: 350/420 x 100= 83.33 ==> 83.3%)
Which statement concerning the mole is not correct?
A mole of any compound contains one mole of each kind of atom found in that compound.
The molar mass of Fe(OH)3 is ________ g.
ANSWER: 106.87 (NOTE: Fe: 55.845 O: 3 x 16.00= 48.00 H: 3 x 1.008 = 3.02 total: 106.87 molar mass)
Calculate the mass of water produced when 2.92 g of butane reacts with excess oxygen. Express your answer to three significant figures and include the appropriate units.
ANSWER: 4.52 g
How many moles of methane are produced when 48.1 moles of carbon dioxide gas react with excess hydrogen gas? Express your answer with the appropriate units. For example, write the unit moles as mol.
ANSWER: 48.1 mol (FORMULA: 48.1 mol CO (1 mole CH4 / 1 mol CO) = 48.1 mol CH4)
A sample of propane, C3H8, contains 14.7 moles of carbon atoms. How many total moles of atoms does the sample contain?
ANSWER: 53.9 (NOTE: 3 carbon + 8 hydrogen= 11 11 x (14.7/3) = 53.9 mol atoms )
In the Sandwiches mode, select the "Cheese sandwich" option and observe the equation given for the preparation of a cheese sandwich. When the number of bread slices and cheese slices is set to "0," you will see that there is "no reaction." Now, in the equation, set the number of bread slices to "2" and the number of cheese slices to "1." You will see that the product formed by these three elements is one cheese sandwich with two slices of bread and one slice of cheese. This equation can be written as 2 bread + cheese → cheese sandwich2 bread + cheese → cheese sandwich Classify the following combination of bread and cheese according to the limiting ingredient in the preparation of the cheese sandwich mentioned above.
Bread is the limiting ingredient:: 4 bread slices and 5 cheese slices 8 bread slices and 5 cheese slices 6 bread slices and 4 cheese slices Cheese is the limiting ingredient: 4 bread slices and 1 cheese slice 8 bread slices and 3 cheese slices 6 bread slices and 2 cheese slices There is no limiting ingredient: 6 bread slices and 3 cheese slices 2 bread slices and 1 cheese slice
Calculate the number of moles of magnesium, chlorine, and oxygen atoms in 5.60 moles of magnesium perchlorate, Mg(ClO4)2. Express the number of moles of Mg, Cl, and O atoms numerically, separated by commas.
EXACT ANSWERS IN ORDER: 5.60,11.2,44.8 (NOTE: Mg=1 x 5.60 moles = 5.60 moles Cl: 2 x 5.60 moles = 11.2 moles O: 4x2=8 x 5.60 moles= 44.8 moles *make sure it's in 3 decimal places)
Calculate the number of moles of aluminum, sulfur, and oxygen atoms in 3.00 moles of aluminum sulfate, Al2(SO4)3. Express the number of moles of Al, S, and O atoms numerically, separated by commas.
EXACT ANSWERS IN ORDER: 6.00, 9.00, 36.0 (NOTE: Al= (2 x 3.00) moles= 6.00 moles S= (3 x 3.00) moles= 9.00 moles O=(4X3=12 x 3.00) moles = 36.0 moles *make sure it's in 3 decimal places)
Balance the chemical reaction equation P4(s)+Cl2(g)→PCl5(g) Enter the coefficients in order, separated by commas (e.g., 1,2,3).
ANSWER: 1,10,4 (FORMULA: P4 + 10Cl2 ===> 4PCl5)
How many moles of nitrogen, N, are in 65.0 g of nitrous oxide, N2O? Express your answer with the appropriate units.
ANSWER: Value: 2.95 Units: mol (FORMULA: 65.0 g N2O x (1 mole N2O/44.01 gN2O) (2 mol N/1 mol N2O)= 2.95 mol N)
What is the mass of 7.50 moles of magnesium chloride, MgCl2? Express your answer with the appropriate units.
ANSWER: Value: 714 Units: g (NOTE: calculate the molar mass: 24.305 Mg + 35.45 (2) Cl= 95.21 g/mo)
How many moles of water, H2O, contain 2.0x10^22 molecules of water? (See the hints for assistance in interpreting scientific notation.) Express the quantity in moles to two significant figures.
ANSWER: .033 mol (NOTE: 2.0 x 10^22 / 6.022 x 10^23= .033 mol)
Calculate the molar mass of norepinephrine (C8H11NO3), a hormone that helps increase blood pressure by stimulating blood vessels to constrict. Express your answer to five significant figures.
ANSWER: 169.18 (NOTE: Molar mass = 12.01(8) + 1.008(11) + 16.00(3) + 14.01(1)= 169.18 g/mol)
Part C Go to the Molecules mode by selecting the icon at the bottom. Notice that there are three real reactions: the synthesis of water, the synthesis of ammonia, and the combustion of methane. Select each of the reactions, and observe the reactants taking part in the reactions. Suppose you are carrying out each of these reactions starting with 5 mol of each reactant. Observe that some reactants are in excess whereas some reactants limit the amount of products formed. Classify each of the reactants as a limiting reactant or an excess reactant for a reaction starting with 5 mol of each reactant. Drag the appropriate items to their respective bins.
Limiting reagent: O2 in combustion of methane H2 in formation of water H2 in formation of ammonia Excess reagent: CH4 in combustion of methane N2 in formation of ammonia O2 in formation of water (NOTE: In the formation of water from 5 mol of hydrogen and 5 mol of oxygen gas, you can form 4 mol of water. Even though oxygen is available, you do not have enough hydrogen gas to produce more water. Thus, you can conclude that hydrogen is the limiting reactant and oxygen is available in excess. In the formation of ammonia from 5 mol of nitrogen and 5 mol of hydrogen gas, you can form 2 mol of ammonia. Here, you are short hydrogen gas; thus, you can conclude that hydrogen is the limiting reactant and nitrogen is in excess. When you combust methane, you need 2 mol of oxygen gas for every mole of methane. If you have 5 mol of methane and 5 mol of oxygen, you can produce 2 mol of carbon dioxide and 4 mol of water. Even though methane is available, you do not have enough oxygen gas to produce more carbon dioxide. Thus, you can conclude that oxygen is the limiting reactant.)
Which of the following combinations of conversion factors could be used to convert atoms of reactant A to grams of product B if given a balanced equation?
atoms A*(moles A/Avogadro's number of atoms)*(moles B/moles A)*(grams B/moles B) (NOTE: All of the conversion factors are correct and the units will cancel, resulting in grams of B.)
Ascorbic acid, or vitamin C (C6H8O6C6H8O6, molar mass = 176 g/mol), is a naturally occurring organic compound with antioxidant properties. A healthy adult's daily requirement of vitamin C is 70-90 mg. A sweet lime contains 2.83×10−4 mol of ascorbic acid. To determine whether the ascorbic acid in a sweet lime meets the daily requirement, calculate the mass of ascorbic acid in 2.83×10−4 mol of ascorbic acid. Express the mass in grams to three significant figures.
0.05 g (FORMULA: 2.83 X10^-4 mol C6H8O6) (176 G C6H8O6) /1 mole C6H8O6)= .049808 ==> 0.50 g C6H8O6 OR change it to scientific notation: 4.98 x 10^-2 g)
How many moles of PCl5 can be produced from 54.0 gg of Cl2 (and excess P4)? Express your answer to three significant figures and include the appropriate units.
0.305 mole (54.0 gCl2 (1 mole Cl2/70.9 gCl2) = 0.762 mol Cl2 0.762 mol Cl2 (4 mol PCl5/10 mol Cl2) .305 mol PCl5)
Acid rain forms in the upper atmosphere by the reaction of sulfur trioxide with water forming sulfuric acid. Calculate the mass in grams of 5.65 × 1021 molecules of SO3.
0.751 g
How many moles of PCl5 can be produced from 29.0 gg of P4 (and excess Cl2)? Express your answer to three significant figures and include the appropriate units.
0.936 mole
Using the following chemical reaction, determine the mole ratio needed to convert from moles of N2 to moles of NH3. N2(g) + H2(g) → NH3(g)
1 mole N2/2 mole NH3 (NOTE: The balanced equation is N2(g) + 3H2(g) → 2NH3(g))
Given the atomic mass of select elements, calculate the molar mass of each salt. Match the numbers to the appropriate blanks in the sentences below. Make certain each sentence is complete before submitting your answer.
1. The molar mass of PdF2 is 144.42 g/mol. 2. The molar mass of MgF2 is 62.31 g/mol 3. The molar mass of CoF2 is 96.93 g/mol 4. The molar mass of BeF2 is 47.01 g/mol (NOTE: PdF2: 106.42+19.00+19.00= 144.42 g/mol)
Caffeine is a bitter stimulant drug and is found in varying quantities in seeds, leaves, and so on. Its formula is C8H10N4O2. Match the number of moles of each element found in the specified number of moles of caffeine. Match the numbers in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.
1. There are 26 mol of hydrogen in 2.6 mol of caffeine. 2. There are 1.6 mol of nitrogen in 0.40 mol of caffeine. 3. There are 16 mol of carbon in 2.0 mol of caffeine. 4. There are 7.0 mol of oxygen in 3.5 mol of caffeine.
The Haber process is used to make ammonia, which is an important source of nitrogen that can be metabolized by plants. Using the equation below, determine how many moles of ammonia will be formed from 8.55 mole of nitrogen. N2(g) + 3 H2(g) → 2 NH3(g)
17.1 mol
Find the number of moles of water that can be formed if you have 194 mol of hydrogen gas and 92 mol of oxygen gas. Express your answer with the appropriate units.
184 mol (FORMULA: 92 X 2= 184 moles of hydrogen NOTE: 92 mol of oxygen will form only 184 mol of water, and 10 mol of hydrogen remain in excess, so the limiting reactant is oxygen and hydrogen is in excess. You can use the Game mode in the simulation to practice these concepts.)
Calculate the molar mass of caffeine (C8H10N4O2). Round to the tenths place.
194.2 g/mol (NOTE: (12.011 amu * 8 C) + (1.00794 amu * 10 H) + (14.0067 amu * 4 N) + (15.9994 amu * 2 O) )
Calculate the mass of butane needed to produce 61.7 g of carbon dioxide. Express your answer to three significant figures and include the appropriate units.
20.4 g
In a reaction to produce chlorine gas, the theoretical yield is 25.6g. What is the actual yield of the reaction if the percent yield is 83.5%?
21.4 g (NOTE: 25.6 x .835 / 100= 21.4)
The fuel for your car is a mixture of octane and several other hydrocarbons. What mass of CO2 will be produced when 125 g of C8H18 react completely in the following equation? 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
386 g (NOTE: this is the correct answer!)
The Haber process is used to make ammonia, which is an important source of nitrogen that can be metabolized by plants. Using the equation below, determine how many kilograms of ammonia will be formed from 89.5 kg of hydrogenN2(g) + 3H2(g) 2NH3(g)
502 kg
A sample of propane, C3H8, contains 14.7 moles of carbon atoms. How many total moles of atoms does the sample contain? Express the total number of moles of carbon and hydrogen numerically.
53.9 moleS
What is the molar mass of butane, C4H10? Express your answer to four significant figures and include the appropriate units.
58.12 g/mol (SOLVED: C4: 4 X 12.011= 48.04 H10: 10 X 1.008 = 10.08 48.04 + 10.08= 58.12 g/mol )
Convert 8 mg of iron into moles. Express your answer to two significant figures and include the appropriate units.
ANSWER: 1.4*10^-4 (use the asterisk a symbol (*) symbol, not the x symbol) (FORMULA: 8 mg Fe (1 g Fe /1,000 mg Fe)(1 mol Fe / 55.845 g Fe) = 1.4x10^-4 )
Sodium hydroxide, NaOH, is a strong base that is used in industrial synthesis and processes such as making paper. What is the mass of 2.60 ×10^22 formula units of NaOH (Molar mass = 40.0 g/molg)? Express the mass in grams to three significant figures.
ANSWER: 1.73 (FORMULA: 2.60 x 10^22 molecule (40.0 gNaOH/6.022 x 10^23 molecule= 1.7270 ==> 1.73 g NaOH)
In the gaseous state, chlorine exists as a diatomic molecule Cl2Cl2 (Molar mass = 70.9 g/mol). Calculate the number of moles of chlorine present in 130 g g of chlorine gas. Express the quantity in moles to three significant figures.
ANSWER: 1.83 (FORMULA: 130 g Cl2 x (1 mol Cl2/70.9 g Cl2)= 1.83 mol Cl2)
How many moles of hydrogen gas would be needed to react with excess carbon dioxide to produce 88.1 moles of water vapor? Express your answer with the appropriate units. For example, write the unit moles as mol.
ANSWER: 176 mol (FORMULA: 88.1 mol H2O (4 mol H2 / 2 mol H2O) = 176.2 ==> 176 mol H2O)
Part B Calculate the molar mass for Mn2O7, an oxide of manganese. Express your answer to five significant figures.
ANSWER: 221.88 (NOTE: Mn: 2 x 54.938= 109.876 O: 7 x 15.999= 111.993 109.876 +111.993= 221.88 molar mass)
In the Sandwiches, mode select the "Cheese sandwich" option and observe the equation given for the preparation of a cheese sandwich. In the equation, set the number of bread slices to "2" and the number of cheese slices to "1." You will see that the product formed by these three ingredients is one cheese sandwich. Suppose you have 46 bread slices and 36 cheese slices. How many cheese sandwiches can you make? Express your answer as an integer.
ANSWER: 23 sandwiches (FORMULA 46 /2 = 23)
Convert 18 mg of iron into moles. Express your answer to two significant figures and include the appropriate units.
ANSWER: 3.2*10^-4 (use the asterisk a symbol (*) symbol, not the x symbol) (FORMULA: 18 mg Fe (1 g Fe /1,000 mg Fe)(1 mol Fe / 55.845 g Fe) = 3.2x10^-4 )
Calculate the number of molecules in 6.00 moles H2S. Express your answer numerically in molecules.
ANSWER: 3.61*10^24 *using the * instead of the x symbol or you will be marked wrong. (FORMULA: 6.00 mol H2S (6.022 x 10^23 H2S molecules/1 mole H2S) = 3.61x10^24)
What is the mass of 7.50 moles of magnesium chloride, MgCl2? Express your answer with the appropriate units.
ANSWER: 715 g (FORMULA: 7.50 moles (95.3 g / 1 mole= 7.15 g)
Calculate the number of moles of Cl atoms in 2.41×1024 formula units of magnesium chloride, MgCl2. Express your answer numerically in moles.
ANSWER: 8.00 mol Cl atoms (FORMULA: 2.41 x 10^24 (1 mol MgCl2 / 6.022 x 10^23) = 4.00 mol MgCl2 4.00 mol MgCl2 (2 mol Cl atoms / 1 mol MgCl2)= 8.00 mol Cl atoms)
