11. how many moles are in 17.987 grams of water (mgcl₂)? 12. approximately how many atoms are in 28.923 grams of na? 13. how many grams of p are there in 3.987 moles 14. what is the molar mass of so₄?

Question

Accepted Answer

### Question 11: How many moles are in 17.987 grams of $ \text{MgCl}_2 $?
# Explanation:
## Step 1: Calculate molar mass of $ \text{MgCl}_2 $
Molar mass of $ \text{Mg} = 24.305 \, \text{g/mol} $, molar mass of $ \text{Cl} = 35.453 \, \text{g/mol} $. For $ \text{MgCl}_2 $, molar mass $ M = 24.305 + 2 \times 35.453 $.
$ M = 24.305 + 70.906 = 95.211 \, \text{g/mol} $
## Step 2: Use moles formula $ n = \frac{m}{M} $
Given $ m = 17.987 \, \text{g} $, $ M = 95.211 \, \text{g/mol} $.
$ n = \frac{17.987}{95.211} \approx 0.189 \, \text{moles} $
# Answer:
$ \approx 0.189 $ moles

### Question 12: Approximately how many atoms are in 28.923 grams of $ \text{Na} $?
# Explanation:
## Step 1: Calculate moles of $ \text{Na} $
Molar mass of $ \text{Na} = 22.99 \, \text{g/mol} $. Using $ n = \frac{m}{M} $, $ m = 28.923 \, \text{g} $, $ M = 22.99 \, \text{g/mol} $.
$ n = \frac{28.923}{22.99} \approx 1.258 \, \text{moles} $
## Step 2: Use Avogadro's number $ N = n \times N_A $
$ N_A = 6.022 \times 10^{23} \, \text{atoms/mol} $.
$ N = 1.258 \times 6.022 \times 10^{23} \approx 7.576 \times 10^{23} \, \text{atoms} $
# Answer:
$ \approx 7.58 \times 10^{23} $ atoms (or similar approximation)

### Question 13: How many grams of $ \text{P} $ are there in 3.987 moles?
# Explanation:
## Step 1: Molar mass of $ \text{P} $
Molar mass of $ \text{P} = 30.974 \, \text{g/mol} $.
## Step 2: Use mass formula $ m = n \times M $
Given $ n = 3.987 \, \text{moles} $, $ M = 30.974 \, \text{g/mol} $.
$ m = 3.987 \times 30.974 \approx 123.5 \, \text{grams} $
# Answer:
$ \approx 123.5 $ grams (or precise calculation: $ 3.987 \times 30.974 \approx 123.49 \approx 123.5 $)

### Question 14: What is the molar mass of $ \text{SO}_4 $? (Assuming $ \text{SO}_4^{2-} $ or neutral? Wait, $ \text{SO}_4 $ as a group: molar mass of $ \text{S} = 32.065 \, \text{g/mol} $, $ \text{O} = 16.00 \, \text{g/mol} $)
# Explanation:
## Step 1: Calculate molar mass
For $ \text{SO}_4 $, molar mass $ M = 32.065 + 4 \times 16.00 $.
$ M = 32.065 + 64.00 = 96.065 \, \text{g/mol} $
# Answer:
$ \approx 96.07 \, \text{g/mol} $ (or 96.065 g/mol)

Sovi.AI - AI Math Tutor

QUESTION IMAGE

Question

Explanation:

Question 11: How many moles are in 17.987 grams of \( \text{MgCl}_2 \)?

Step 1: Calculate molar mass of \( \text{MgCl}_2 \)

Step 2: Use moles formula \( n = \frac{m}{M} \)

Step 1: Calculate moles of \( \text{Na} \)

Step 2: Use Avogadro's number \( N = n \times N_A \)

Step 1: Molar mass of \( \text{P} \)

Step 2: Use mass formula \( m = n \times M \)

Answer:

Question 12: Approximately how many atoms are in 28.923 grams of \( \text{Na} \)?