Question

1. 0.00500 grams ne

convert to mass in grams

1. 10.0 moles na
2. 2.20 moles sn
3. 5.00 moles ag
4. $1.00 \times 10^{7}$ moles b
5. $6.02 \times 10^{23}$ atoms ca
6. $1.204 \times 10^{23}$ atoms bi

Explanation:

Step1: Get Na molar mass

Molar mass of Na = $22.99\ \text{g/mol}$

Step2: Calculate mass of Na

$\text{Mass} = \text{Moles} \times \text{Molar Mass} = 10.0\ \text{mol} \times 22.99\ \text{g/mol} = 229.9\ \text{g}$

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Step1: Get Sn molar mass

Molar mass of Sn = $118.71\ \text{g/mol}$

Step2: Calculate mass of Sn

$\text{Mass} = 2.20\ \text{mol} \times 118.71\ \text{g/mol} = 261.162\ \text{g}$

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Step1: Get Ag molar mass

Molar mass of Ag = $107.87\ \text{g/mol}$

Step2: Calculate mass of Ag

$\text{Mass} = 5.00\ \text{mol} \times 107.87\ \text{g/mol} = 539.35\ \text{g}$

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Step1: Get B molar mass

Molar mass of B = $10.81\ \text{g/mol}$

Step2: Calculate mass of B

$\text{Mass} = 1.00 \times 10^7\ \text{mol} \times 10.81\ \text{g/mol} = 1.081 \times 10^8\ \text{g}$

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Step1: Convert atoms to moles

Use Avogadro's number $N_A = 6.02 \times 10^{23}\ \text{atoms/mol}$
$\text{Moles of Ca} = \frac{6.02 \times 10^{23}\ \text{atoms}}{6.02 \times 10^{23}\ \text{atoms/mol}} = 1.00\ \text{mol}$

Step2: Get Ca molar mass & calculate mass

Molar mass of Ca = $40.08\ \text{g/mol}$
$\text{Mass} = 1.00\ \text{mol} \times 40.08\ \text{g/mol} = 40.08\ \text{g}$

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Step1: Convert atoms to moles

$\text{Moles of Bi} = \frac{1.204 \times 10^{23}\ \text{atoms}}{6.02 \times 10^{23}\ \text{atoms/mol}} = 0.200\ \text{mol}$

Step2: Get Bi molar mass & calculate mass

Molar mass of Bi = $208.98\ \text{g/mol}$
$\text{Mass} = 0.200\ \text{mol} \times 208.98\ \text{g/mol} = 41.796\ \text{g}$

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Step1: Note for Q8

0.00500 grams Ne is already in grams, no conversion needed.

Answer:

1. 0.00500 grams
2. 230 g (rounded to 3 sig figs)
3. 261 g (rounded to 3 sig figs)
4. 539 g (rounded to 3 sig figs)
5. $1.08 \times 10^8$ g (rounded to 3 sig figs)
6. 40.1 g (rounded to 3 sig figs)
7. 41.8 g (rounded to 3 sig figs)