Deck 2: Chemical Measurements

Question 1

The recommended daily allowance of calcium for men between the ages of 19 to 50 is 1 000 mg Ca.Three multivitamin tablets are analyzed for calcium gravimetrically with the precipitation of calcium cation by oxalate anion.If the mass dry calcium oxalate obtained is 2.0136 g,how many tablets must a man take in a given day to meet the recommended daily allowance?
Ca²⁺ (aq)+ C₂O₄²⁻ (aq) $\rightarrow$ CaC₂O₄ (s)

Answer 1

five vitamin tablets

Question 2

The planet Mars orbits 2.279 *10¹¹ m from the Sun.Express the distance using the appropriate prefix.

A)227.9 Gm
B)227.9 mM
C)2.279 km
D)22.79 nm
E)None of these is correct.

Answer 2

227.9 Gm

Question 3

A student must prepare 500.0 mL of solution containing 0.999 grams of solid copper(II)sulfate.Which of the following statements are FALSE regarding the proper procedure to prepare this solution?
I The 0.999 grams of solid copper(II)sulfate is dissolved in a 500.0-mL volumetric flask containing 500.0 mL of water.
II The 0.999 grams of solid copper(II)sulfate is dissolved in a 500.0-mL volumetric flask containing 400 mL of distilled water before dilution to 500.0-mL.
III The 0.999 grams of solid copper(II)sulfate is placed in an empty 500.0-mL volumetric flask,diluted to 500.0 mL and allowed to dissolve.

A)I and II
B)II and III
C)I and III
D)I,II,and III
E)None are false.

Answer 3

I and III

Question 4

Which of the statements below are TRUE for expressing the concentration of a 54.9-ppm Fe solution in terms of molarity?
I Iron's molar mass must be known to calculate the moles iron in solution.
II Iron's density must be known to calculate the mass iron in solution.
III The solution density must be known to calculate the solution volume.
IV The type of glassware used to prepare the solution must be known.

A)I,III,and IV
B)I and II
C)I and III
D)II and III
E)None of these is true.

Question 5

A mixture of 50.00 grams propane,C₃H₈,and 100.00 grams oxygen,O₂,is combusted.____________________is the limiting reactant and____________________ grams of____________________ is in excess.(C₃H₈ = 44.10 g/mol) C₃H₈ (g)+ 5 O₂ (g) $\rightarrow$ 3 CO₂ (g)+ 4 H₂O (g)

A)Propane;22.44;oxygen
B)Oxygen;63.71;propane
C)Oxygen;22.42;propane
D)Propane;27.44;oxygen
E)None of these answers is correct.

Question 6

The sulfur content of an ore is determined gravimetrically by reacting the ore with concentrated nitric acid and potassium chlorate,converting all sulfur to sulfate.The excess nitrate and chlorate is removed by reaction with concentrated hydrochloric acid and the sulfate is precipitated using barium cation. Ba²⁺ (aq)+ SO₄^2- (aq) $\rightarrow$ BaSO₄ (s)
Analysis of 10.1830 grams of a sulfur containing ore yielded 13.0221 grams of BaSO₄.What is the percent by mass sulfur in the ore? (BaSO₄ = 233.43 g/mol)

A)32.18%
B)52.63%
C)10.74%
D)17.57%
E)The answer cannot be calculated with available data.

Question 7

Calculate the mass of Na₂CO₃ needed to prepare a 15.00 mM solution with a volume of 500.0 mL.(Na₂CO₃ = 105.9888 g/mol)

A)1)258 g
B)3)180 g
C)0)7949 g
D)7)076 g
E)0)0141 g

Question 8

What volume of a 50.0% by mass NaOH solution must be diluted to prepare a 0.3500 M NaOH solution with a volume of 500 mL? The density of 50% NaOH solution is 1.515 g/mL at 25°C.(NaOH = 40.00 g/mol)

Question 9

The calorie content of a candy bar is 230 calories per serving (1 bar).Calculate the specific energy (kJ/g)of the candy bar.(1 candy bar = 52.7 g,1 calorie = 4.184 J)

A)2.90 *10³ kJ/g
B)18.3 kJ/g
C)1.83 * 10⁻² kJ/g
D)5.07* 10⁴ kJ/g
E)9.59* 10⁻¹ kJ/g

Question 10

Calculate the molarity of a 30.0% hydrogen peroxide solution.The reported density of 30% hydrogen peroxide is 1.135 g/cm³.(H₂O₂ = 34.0147 g/mol)

A)7)77 M
B)0)0100 M
C)0)100 M
D)10.0 M
E)8)82 M

Question 11

What volume of 12.1 M HCl must be diluted to prepare a 0.2500 M HCl solution with a volume of 2.000 L?

A)41.3 mL
B)96.8 mL
C)10.3 mL
D)24.2 mL
E)6)05 mL

Question 12

The maximum contaminant level for arsenic is 0.010 ppm for drinking water per EPA regulation.The arsenic concentration for the drinking water of a municipality was measured to be 4.92 * 10⁻⁶ M arsenic.What is the arsenic concentration of the water sample in ppm? Does the water sample meet EPA guidelines? Assume the drinking water sample has a density of 1.0000 g/mL.

Question 13

On average one gallon of kerosene contains 135,000 BTUs of heat energy per gallon combusted.Convert the energy content of kerosene to SI units.(1 BTU = 1055 J)

Question 14

An NaCl solution is labeled as having a concentration of 33.5% by mass.If the NaCl solution has a density of 1.0492 g/mL,what is the molarity of the solution? (NaCl= 58.44 g/mol)

Question 15

Calculate the mass NaCH₃CO₂ contained in 500.0 mL of a 0.1500 M NaCH₃CO₂ solution.(NaCH₃CO₂ = 82.0343 g/mol)

A)914.3 µg
B)283.4 g
C)24.61 µg
D)6)378 g
E)24.61 g

Question 16

What volume of a 36% HCl solution must be diluted to prepare 1.000 L of a 0.1000 M HCl solution? The density of 36% HCl is 1.18 g/mL.

A)11.7 mL
B)8)6 mL
C)1)2 mL
D)10.1 mL
E)64.6 mL

Question 17

A satellite in low Earth orbit with a circular orbit has an orbital speed of 7.3 km/s relative to the Earth's surface.Calculate the satellite's speed in miles per hour.

A)1.6 * 10⁴ mile per hour
B)1.3 * 10⁻³ mile per hour
C)4.2 *10⁴ mile per hour
D)3.3 *10⁻³ mile per hour
E)3.1 * 10² mile per hour

Question 18

The gas mileage for a new car model destined for sale in Europe must be determined for regulatory and promotional purposes.If the car uses 10.5 gallons to travel 250 miles,what is the gas mileage in km/L?

A)174 km/L
B)3)25 km/L
C)67.3 km/L
D)14.9 km/L
E)10.1 km/L

Question 19

When solutions of Pb²⁺ and CrO₄²⁻ are mixed the precipitate PbCrO₄ is produced.What volume of 0.1750 M CrO₄²⁻ removes all lead from 50.00 mL of a 0.3400 M Pb²⁺ solution?

A)97.14 mL
B)25.74 mL
C)48.57 mL
D)194.29 mL
E)75.00 mL

Question 20

Arrange the four microscopic views below of four different solutions in order of increasing concentration.

A)I,II,III,and IV
B)II,III,I,and IV
C)IV,II,III,and I
D)IV,I,III,and II
E)III,IV,II,and I

Question 21

Aqueous lead precipitates when mixed with aqueous carbonate.
Pb²⁺ (aq)+ CO₃²⁻ (aq) $\rightarrow$ PbCO₃ (s)
If 5.000 g Pb(NO₃)₂ and 2.500 g Na₂CO₃ are mixed in water,which ion is the limiting reactant? What mass PbCO₃ is precipitated? (PbCO₃ = 267.21 g/mol,Pb(NO₃)₂ = 331.2 g/mol,Na₂CO₃ = 105.9888 g/mol)