Chem 103 Exam 3 real thing Ferris State Actual Questions And Detailed Correct Answers.

8.1-8.3 A conversion factor is a ratio that shows the relationship between two units. - correct answer True The units in the numerator of a conversion factor differ from the units in the denominator. - correct answer true Multiplying a measured value by a conversion factor does not change the size of the thing was measured, just the way it is expressed. - correct answer true By definition, 1 in = 2.54 cm. We obtain two conversion factors, the first by dividing both sides of the equality by 1 in to give - correct answer 2.54cm/1 inch Which is an appropriate conversion factor for converting grams to kilograms? - correct answer 1k/ 1000g 1ug/10^6g is the correct conversion factor for relating grams to micrograms. - correct answer false Choose the correct set-up for converting 14 inches to centimeters. - correct answer ? cm= 14 in (2.54cm /1 inch) Elemental sulfur is used to control fungal diseases on plants. The recommend dosage for spraying roses is 2 tablespoons per gallon of water. How many teaspoons of powder should be added to a 1 quart spray bottle? Write the problem out, just answer. Be consistent. Always use the framework shown in Example 8.2 on pages 290-291. Useful equalities: 3 tsp = 1 Tbsp = 0.5 fl oz, and 4 qt = 1 gal - correct answer 1.5 tsp/qt The density of a substance is calculated using its mass and the volume. - correct answer true Density is a measure of the amount of matter in a given space. - correct answer true The density of a substance is independent of its temperature. - correct answer True The mass of an object is 14.643 g. The volume occupied by the object is 12.6 mL. What is its density? - correct answer 1.16 g/mL Exact values and numbers generated by counting do not influence significant figure determination. - correct answer true A pick-up truck measures 19 feet, six inches. What is its length in meters? Write the problem out, just answer. Be consistent. Always use the framework shown in Example 8.2 on pages 290-291. Useful equalities: 12 in = I ft, 2.54 cm = 1 in, 100 cm = 1 m. - correct answer 5.94 m Measured and calculated values are uncertain and so influence significant figure determination. - correct answer True What is the combined mass of a stone with mass 12.624 g and a stone with 148.2 g? - correct answer 160.8 g More than 168,000 cubic meters of water go over Niagara Falls each minute. How many gallons of water flow over the falls per second? Write the problem out, just answer. Be consistent. Always use the framework shown in Example 8.2 on pages 290-291. Useful equalities: 103 L = 1 m3, 3.785 L = 1 gal, 60 s = 1 min. - correct answer 7.40 x 105 gal/s 8.4-8.6 Saying that dry air is 20.95% oxygen by volume means - correct answer 20.95L O2/ 100.00L air x100 The average density of seawater at the surface of the oceans is 1.025 g/mL. The average salt content (salinity) is 3.5%. How many grams of salt are there in 500 mL of seawater? - correct answer 18 g Saying that there are 640 acres per square mile means - correct answer Although both are correct, the language used is 640 acres/ 1 mile A house has 40 rows of shingles, with 50 shingles per row. Each shingle was fastened with 4 nails. Each nail weighs 0.10 oz. How many pounds of nails were used? - correct answer 50 lb A gardener needs to fertilize her three year old apple trees. She learns that she should apply 1/8 lb of actual nitrogen per year according to the age of the tree. She has a bag of 19-19-19 fertilizer, which means that the bag contains 19 % nitrogen, 19% phosphorus and 19% potassium by weight. The bulk density of the granular material is about 60 lb/ft3. How many cups of fertilizer should she spread around each tree? Some useful equalities: 1 ft3 = 6.43 gal, 1 gal = 4 qts, 1 qt = 4 cups. - correct answer 3 cups How many dietary Calories can you burn by drinking eight 16 ounce glasses of ice water per day? Helpful: Ice water starts at 0 degree C. Body temp is 37 degree C. 1 fluid oz= 29.574mL. 1 cal= 1000cal. One calorie, cal is the amount of heat energy that will raise the temp of 1 mL water by 1 degree C, so 1 cal= 1 mL water x1 degree C increase. 1 mLx1 degree C/ 1 cal and 1 cal/ 1 mLx1 degree C. - correct answer 140 Cal Question 7. I'm not writing it out. What will the Celsius thermometer read when the lab temperature is 79 degree F? - correct answer 26 degree C Acetic acid has a melting point of 16.6oC. Pure acetic acid is called glacial acetic acid, because icy looking crystals can be seen in the bottle on cold winter days. What Fahrenheit temperature does the chemistry lab have to be lower than in order to see those crystals? - correct answer 61.9 degree F 9.1-9.3 In this chapter we will learn how to calculate the amount of product we might form in a chemical reaction using the _______. - correct answer All of these: chemical formulas of the compounds balanced reaction equation atomic mass (or weight) of the elements from the periodic table he atomic mass of an element is the weighted average of the masses of the isotopes expressed in _____; it takes the relative abundance of each isotope into account. The atomic weight of an element is the atomic mass expressed in ______. - correct answer amu / g mol^-1 Avogadro's number, 6.022 x 10^23, is the number of carbon-12 atoms in _______ of carbon-12. - correct answer 12g Avogadro's number of particles represents one _______ of the particles. - correct answer Mol Use unit analysis to determine the mass in g of 3.000 moles iron (Fe). Remember to write out the full problem, starting with ? g = ... Always show your work. Include all units at every step of the way. Keep track of significant figures. - correct answer 167.5 g The molar mass of an element is the mass of _____ atoms of the element. - correct answer 6.022 x 10^23 The molar mass of an element is the atomic mass of the element expressed in ________. - correct answer g mol^-1 The molar mass of a molecular compound (the molecular mass) is calculated by adding the atomic masses of all the atoms in the compound and expressing the result in g/mol. - correct answer True What is the molar mass of methane, CH4? - correct answer 16.04 g mol^-1 One mole of elemental carbon = 12.011 g of carbon. - correct answer True The molar mass of carbon dioxide, CO2, is 44.01 g/mol. What is the mass of 2.00 moles of CO2? - correct answer 88.0 g The molar mass of an ionic compound is calculated by adding the atomic masses of all the atoms in the ________ of the compound and expressing the result g/mol. - correct answer formula unit Calculate the formula mass for NaOH. - correct answer 40.00 g/mol o say that the molecular mass of water, H2O, is 18.02 g/mol leads to the following conversion factor. - correct answer 18.02 g water/ 1 mol water and 1 mol water/ 18.02 g water both are the correct answer 9.4-9.5 The oxidation of iron metal yields iron(III) oxide, or rust. 4 Fe(s) + 3 O2(g) →Fe2O3(s). - correct answer 159.69 g/mol Provide a conversion factor that relates moles of oxygen atoms to moles of Fe2O3. - correct answer 1 mol Fe2O3/3 mol O and 3 mol O/1 mol Fe2O3 both of these Provide a conversion factor that relates moles of iron atoms to moles of oxygen atoms in Fe2O3. - correct answer 2 mol Fe/ 3 mol O Calculate the mass in grams of 4.0 moles of Fe2O3. - correct answer 640 g How many grams of oxygen are present in 3.00 moles of Fe2O3? - correct answer 144g How many grams of rust will be formed through oxidation of 32 g of Fe? - correct answer 46 g What is the empirical formula of a compound that is 40.05 % sulfur by mass, and 59.95 % oxygen? - correct answer SO3 10.1-10.2 Provide a conversion factor that relates moles of one reactant or product in the reaction provided to moles of another reactant or product in this reaction. 3 H2(g) + WO3(s) −− W(s) + 3 H2O(l) - correct answer (1 mole WO3) / (3 mole H2O) Consider the combustion of octane, a major component of gasoline, in excess oxygen. 2 C8H18(g) + 25 O2(g) −− 16 CO2(g) + 18 H2O(g) How many moles of CO2 are produced when 451 moles of C8H18 is burned? - correct answer 3610 mol CO2 Consider the combustion of octane, a major component of gasoline, in excess oxygen. 2 C8H18(g) + 25 O2(g) −− 16 CO2(g) + 18 H2O(g) How many moles of oxygen are consumed in the combustion of 585 moles of C8H18? - correct answer 7310 mol O2 Show the necessary strategy required to calculate the amount of tungsten, W formed when 50.0 kg of tungsten(VI) oxide is heated with hydrogen gas, H2. - correct answer 50.0 kg WO3 ⇨ g WO3 ⇨ mole WO3 ⇨ mole W ⇨ g W ⇨ kg W Lead(II) oxide reacts with ammonia according to: PbO(s) + NH3(g) −− Pb(s) + N2(g) + H2O(l) This equation is not balanced. It must be balanced before it can be used for calculations: How many moles of water form for every mole of nitrogen gas that forms? - correct answer 3 Lead(II) oxide reacts with ammonia according to: PbO(s) + NH3(g) −−; Pb(s) + N2(g) + H2O(l) This equation is not balanced. It must be balanced before it can be used for calculations: Calculate how many grams of Pb(s) would be formed if 27.0 g of PbO was reacted. - correct answer 25.1 g Pb It is not uncommon, in a chemical reaction, for one of the reactants to be completely consumed before the all of the other reactants have a chance to react, leaving those reactants in the product mixture. The reactant that runs out first is called the ________. - correct answer limiting reagent This reactant [that ran out first] determines the maximum amount of product that can be formed, know as the ________. - correct answer theoretical yield The ratio of product obtained to the amount of product predicted by the limiting reagent, multiplied by 100 is the ______ of the reaction. - correct answer percent yield Examine the reaction of magnesium metal, Mg with nitrogen gas, N2: 3 Mg(s) + N2(g) −− Mg3N2(s) If 2.0 moles of magnesium metal are reacted with 2.0 moles of nitrogen gas, how many moles of magnesium nitride can be formed? - correct answer 2/3 mol Examine the reaction of magnesium metal, Mg with nitrogen gas, N2: