The answer is b) light waves travel faster than sound waves.
Answer:

Explanation:
There are no molecules in NaCl, because it consists only of ions.
However, we can calculate the number of formula units (FU) of NaCl.
Step 1. Calculate the moles of NaCl

Step 2. Convert moles to formula units

There are
in 3.6 g of NaCl.
Answer: The final temperature of both the weight and the water at thermal equilibrium is
.
Explanation:
The given data is as follows.
mass = 7.62 g, 
Let us assume that T be the final temperature. Therefore, heat lost by water is calculated as follows.
q =
= 
Now, heat gained by lead will be calculated as follows.
q =
=
According to the given situation,
Heat lost = Heat gained
= 
T = 
Thus, we can conclude that the final temperature of both the weight and the water at thermal equilibrium is
.
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