Chem 103 Exam 3 real thing Ferris State

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)

(1 mole WO3) / (3 mole H2O)

How many moles of NaCl are required to prepare 52.0 mL of a 3.60 M solution of NaCl?

0.187 mol

Provide a conversion factor that relates moles of oxygen atoms to moles of Fe2O3.

1 mol Fe2O3/3 mol O and 3 mol O/1 mol Fe2O3 both of these

The mass of an object is 14.643 g. The volume occupied by the object is 12.6 mL. What is its density?

1.16 g/mL

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

1.5 tsp/qt

Avogadro's number, 6.022 x 10^23, is the number of carbon-12 atoms in _______ of carbon-12.

12g

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.

140 Cal

How many grams of oxygen are present in 3.00 moles of Fe2O3?

144g

How many mL of a 4.00 M stock solution of AgNO3 are required to prepare a 0.300 L of a 0.200 M AgNO3 solution? [Hint: Begin with the given measured quantity—what amount are you asked to prepare? Start from the back and work forward. You know the volume of solution you are asked to prepare. You know the requested solution concentration—convert it to moles. Once you know how many moles there must be in the final preparation, you know how many moles you must begin with—those moles are supplied by the original stock solution. Calculate volume of stock solution required using the stock solution's concentration. Do this all in one step—write one string of conversion factors, making sure units cancel to give mL in the final answer.]

15.0 mL

9.4-9.5 The oxidation of iron metal yields iron(III) oxide, or rust. 4 Fe(s) + 3 O2(g) →Fe2O3(s).

159.69 g/mol

What is the combined mass of a stone with mass 12.624 g and a stone with 148.2 g?

160.8 g

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.

167.5 g

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?

18 g

o say that the molecular mass of water, H2O, is 18.02 g/mol leads to the following conversion factor.

18.02 g water/ 1 mol water and 1 mol water/ 18.02 g water both are the correct answer

Which is an appropriate conversion factor for converting grams to kilograms?

1k/ 1000g

Provide a conversion factor that relates moles of iron atoms to moles of oxygen atoms in Fe2O3.

2 mol Fe/ 3 mol O

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

2.54cm/1 inch

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?

2/3 mol

8.4-8.6 Saying that dry air is 20.95% oxygen by volume means

20.95L O2/ 100.00L air x100

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.

25.1 g Pb

Calculate the percent yield if 35.00 g of magnesium was reacted with an excess of nitrogen and 12.56 g of magnesium nitride was formed.

25.92 %

Question 7. I'm not writing it out. What will the Celsius thermometer read when the lab temperature is 79 degree F?

26 degree C

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?

3

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.

3 cups

To calculate the molarity of a solution, remember, molarity is solution concentration expressed in moles solute / L solution. To calculate molarity, start by writing a fraction, amount of solute / volume solution, using whatever units for amount and volume were given in the problem. Then, use conversion factors to get the numerator to units of moles, and the denominator to units of liters. Calculate the molarity, M of a solution of sodium chloride containing 1.5 moles NaCl dissolved in 500 mL of NaCl solution.

3.0 mol/L

An ammonium chloride solution was prepared by dissolving 42.843 g of NH4Cl in water and then diluting the solution with water to give 250.00 mL. What is the solution's molarity?

3.2037 M

A chemical test used by geologists for detecting limestone is to treat the rock with a hydrochloric acid solution and watch for the formation of bubbles of carbon dioxide gas. CaCO3(s) + 2 HCl(aq) −−> CaCl2(aq) + H2O(l) + CO2(g) How many grams of CaCO3(s) are consumed in a reaction with 225 mL of 3.25 M HCl? [Hint: What quantity are you given? Start by converting it to moles. Then, look at the balanced equation to find a conversion factor for getting from mol HCl to mol CaCO3. That brings you close to the end.]

36.6 g

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?

3610 mol CO2

When solving solution stoichiometry problems—finding one value from another by use of concentration and other conversion factors, always begin with the measured quantity—the measurable you are given, or the measurable you are seeking. How many moles of NaCl are required to prepare 1.0 L of a 4.0 M solution of NaCl? [Hint: start your calculation with 1.0 L NaCl soln]

4.0 mol

How many grams of rust will be formed through oxidation of 32 g of Fe?

46 g

Examine the reaction of magnesium metal, Mg with nitrogen gas, N2: 3 Mg(s) + N2(g) −−> Mg3N2(s) If 35.00 g of magnesium is reacted with an excess of nitrogen, what is the theoretical yield of magnesium nitride?

48.45 g

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.

5.94 m

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?

50 lb

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.

50.0 kg WO3 ⇨ g WO3 ⇨ mole WO3 ⇨ mole W ⇨ g W ⇨ kg W

What volume of 2.00 M CuSO4 solution contains 0.100 mol CuSO4?

50.0 mL

The molar mass of an element is the mass of _____ atoms of the element.

6.022 x 10^23

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?

61.9 degree F

Calculate the mass in grams of 4.0 moles of Fe2O3.

640 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.

7.40 x 105 gal/s

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?

7310 mol O2

How many liters of 4.84 M NaCl can we prepare with 2.60 kg of NaCl? [Hint: Begin with the given measured quantity, convert it to moles and calculate volume using the solution concentration. Do this all in one step—write one string of conversion factors, making sure units cancel to give L in the final answer.]

9.17 L

Choose the correct set-up for converting 14 inches to centimeters.

? cm= 14 in (2.54cm /1 inch)

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 _______.

All of these: chemical formulas of the compounds balanced reaction equation atomic mass (or weight) of the elements from the periodic table

Saying that there are 640 acres per square mile means

Although both are correct, the language used is 640 acres/ 1 mile

Avogadro's number of particles represents one _______ of the particles.

Mol

8.1-8.3 A conversion factor is a ratio that shows the relationship between two units.

True

Measured and calculated values are uncertain and so influence significant figure determination.

True

The density of a substance is independent of its temperature.

True

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.

True

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 ______.

amu / g mol^-1

While it is easy to measure solution volumes, it is not possible to relate solution volume to moles of solute unless you know the solution _______.

concentration

1ug/10^6g is the correct conversion factor for relating grams to micrograms.

false

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.

formula unit

The molar mass of an element is the atomic mass of the element expressed in ________.

g mol^-1

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 ________.

limiting reagent

Examine the reaction of magnesium metal, Mg with nitrogen gas, N2: 3 Mg(s) + N2g) → Mg3N2(s) What is the limiting reagent, if 2 moles of magnesium are reacted with 2 moles of nitrogen?

magnesium

The ratio of product obtained to the amount of product predicted by the limiting reagent, multiplied by 100 is the ______ of the reaction.

percent yield

When reactants are dissolved in a solvent, they are better able to collide with each other, increasing the probability of ______.

reaction

10.3 Solution chemistry is the chemistry of reactants in _______.

solution in a solvent

This reactant [that ran out first] determines the maximum amount of product that can be formed, know as the ________.

theoretical yield

Density is a measure of the amount of matter in a given space.

true

Exact values and numbers generated by counting do not influence significant figure determination.

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.

true

The density of a substance is calculated using its mass and the volume.

true

The units in the numerator of a conversion factor differ from the units in the denominator.

true

What is the molar mass of methane, CH4?

16.04 g mol^-1

Calculate the formula mass for NaOH.

40.00 g/mol

The molar mass of carbon dioxide, CO2, is 44.01 g/mol. What is the mass of 2.00 moles of CO2?

88.0 g

What is the empirical formula of a compound that is 40.05 % sulfur by mass, and 59.95 % oxygen?

SO3

One mole of elemental carbon = 12.011 g of carbon.

True