Question

post - test activity
please answer the following questions in a one whole sheet of yellow paper. submit your outputs through canvas.

1. calculate, to two decimal places, the formula mass of each of the following substances. obtain the needed atomic masses from the inside front cover of the text.

a. c₁₂h₂₂o₁₁ (sucrose, table sugar)
b. c₇h₁₆ (heptane, a component of gasoline)
c. c₁₄h₁₈n₂o₅ (saccharin, an artificial sweetener)
d. (nh₄)₂so₄ (ammonium sulfate, a lawn fertilizer)
indicate the number of objects present in each of the following quantities.
a. number of oranges in 1.00 mole of oranges
b. number of camels in 1.00 mole of camels
c. number of atoms in 1.00 mole of cu atoms
d. number of molecules in 1.00 mole of co molecules

1. what is the mass, in grams, of 1.000 mole of each of the following substances?

a. ca (calcium)
b. ag (silver)
c. no (nitric oxide)
d. hno₃ (nitric acid)

1. how much, in grams, does each of the following quantities of matter weigh?

a. 3.00 moles of p atoms
b. 2.00 moles of so₂ molecules
c. 5.00 moles of cl atoms
d. 5.00 moles of cl₂ molecules

Explanation:

Step1: Recall molar - mass formula

The molar mass $M$ of a compound is the sum of the molar masses of its constituent atoms. The molar mass of an element is equal to its atomic mass (from the periodic table) in g/mol.

Step2: Calculate molar mass of $C_{12}H_{22}O_{11}$ (sucrose)

The atomic masses of $C = 12.01\ g/mol$, $H = 1.01\ g/mol$, and $O = 16.00\ g/mol$.
$M_{C_{12}H_{22}O_{11}}=12\times12.01 + 22\times1.01+11\times16.00$
$=144.12+22.22 + 176.00$
$=342.34\ g/mol$

Step3: Calculate molar mass of $C_7H_{16}$ (heptane)

$M_{C_7H_{16}}=7\times12.01+16\times1.01$
$=84.07+16.16$
$=100.23\ g/mol$

Step4: Calculate molar mass of $C_{14}H_{18}N_2O_5$ (saccharin)

$M_{C_{14}H_{18}N_2O_5}=14\times12.01+18\times1.01 + 2\times14.01+5\times16.00$
$=168.14+18.18+28.02 + 80.00$
$=294.34\ g/mol$

Step5: Calculate molar mass of $(NH_4)_2SO_4$ (ammonium sulfate)

$M_{(NH_4)_2SO_4}=2\times(14.01 + 4\times1.01)+32.07+4\times16.00$
$=2\times(14.01+4.04)+32.07 + 64.00$
$=2\times18.05+32.07+64.00$
$=36.10+32.07+64.00$
$=132.17\ g/mol$

Step6: Calculate mass of 1.000 mole of substances

The mass $m$ of a substance in grams is given by $m = n\times M$, where $n$ is the number of moles and $M$ is the molar mass.
For $Ca$ (calcium), $M_{Ca}=40.08\ g/mol$, $m_{Ca}=1.000\ mol\times40.08\ g/mol = 40.08\ g$
For $Ag$ (silver), $M_{Ag}=107.87\ g/mol$, $m_{Ag}=1.000\ mol\times107.87\ g/mol = 107.87\ g$
For $NO$ (nitric oxide), $M_{NO}=14.01+16.00 = 30.01\ g/mol$, $m_{NO}=1.000\ mol\times30.01\ g/mol = 30.01\ g$
For $HNO_3$ (nitric acid), $M_{HNO_3}=1.01+14.01+3\times16.00$
$=1.01+14.01 + 48.00$
$=63.02\ g/mol$, $m_{HNO_3}=1.000\ mol\times63.02\ g/mol = 63.02\ g$

Step7: Calculate mass of given - mole quantities

For 3.00 moles of $P$ atoms, $M_P = 30.97\ g/mol$, $m_P=3.00\ mol\times30.97\ g/mol = 92.91\ g$
For 2.00 moles of $SO_2$ molecules, $M_{SO_2}=32.07+2\times16.00 = 64.07\ g/mol$, $m_{SO_2}=2.00\ mol\times64.07\ g/mol = 128.14\ g$
For 5.00 moles of $Cl$ atoms, $M_{Cl}=35.45\ g/mol$, $m_{Cl}=5.00\ mol\times35.45\ g/mol = 177.25\ g$
For 5.00 moles of $Cl_2$ molecules, $M_{Cl_2}=2\times35.45\ g/mol = 70.90\ g/mol$, $m_{Cl_2}=5.00\ mol\times70.90\ g/mol = 354.50\ g$

Step8: Recall Avogadro's number

Avogadro's number $N_A=6.022\times 10^{23}\ mol^{-1}$.
The number of objects in $n$ moles is $N=n\times N_A$.
For 1.00 mole of oranges, the number of oranges is $N = 1.00\ mol\times6.022\times 10^{23}\ mol^{-1}=6.022\times 10^{23}$
For 1.00 mole of camels, the number of camels is $N = 1.00\ mol\times6.022\times 10^{23}\ mol^{-1}=6.022\times 10^{23}$
For 1.00 mole of $Cu$ atoms, the number of $Cu$ atoms is $N = 1.00\ mol\times6.022\times 10^{23}\ mol^{-1}=6.022\times 10^{23}$
For 1.00 mole of $CO$ molecules, the number of $CO$ molecules is $N = 1.00\ mol\times6.022\times 10^{23}\ mol^{-1}=6.022\times 10^{23}$

Answer:

1.

• $C_{12}H_{22}O_{11}$: $342.34\ g/mol$
• $C_7H_{16}$: $100.23\ g/mol$
• $C_{14}H_{18}N_2O_5$: $294.34\ g/mol$
• $(NH_4)_2SO_4$: $132.17\ g/mol$

2.

• Oranges: $6.022\times 10^{23}$
• Camels: $6.022\times 10^{23}$
• $Cu$ atoms: $6.022\times 10^{23}$
• $CO$ molecules: $6.022\times 10^{23}$

3.

• $Ca$: $40.08\ g$
• $Ag$: $107.87\ g$
• $NO$: $30.01\ g$
• $HNO_3$: $63.02\ g$

4.

• $P$ atoms: $92.91\ g$
• $SO_2$ molecules: $128.14\ g$
• $Cl$ atoms: $177.25\ g$
• $Cl_2$ molecules: $354.50\ g$