Answer:
39.02 amu
Explanation:
The average atomic mass of an element can be calculated as follows :

So, the atomic mass of the element X is 39.02 amu.
Answer:

Explanation:
In multiplication and division problems, the answer can have no more significant figures than the number with the fewest significant figures.
A calculator gives the result:

163.8 has four significant figures.
8.64 has three significant figures.
You must round to three significant figures.
That is, you drop all the digits to the right of the 9 — the red line in Fig. 1 below. You are rounding to the nearest tenth.
To round a number to the nearest tenth, you look at the digit in the hundredths place (7). See Fig. 2.
If the digit to be dropped is greater than 5 or is 5 followed by at least one non-zero digit, you add 1 to the number in the tenths place (Fig. 3).
Here's how you do it.
- The digit in the hundredths place is 5 followed by non-zero digits.
- Add 1 to the digit in the tenths place (9).
- ⁹/₁₀ + ⅒ = ¹⁰/₁₀ = 1 + ⁰/₁₀ = 1.0
The tenths digit becomes 0 and the ones digit increases from 8 to 9.

Answer:
A
Explanation:
temperature increase because burning causes heat therefore the planet heats up from all the fossil fuels burned aka "global warming"
It has 5 unpaired electrons
Answer:
b. In equilibrium with the liquid phase, the pressure exerted by a gas.
Explanation:
When a liquid is warmed up to a temperature , it starts vaporising . The liquid is turning into gas and gas is turning into liquid at different rates . Initially the rate of former is higher but gradually the difference of rate between them decreases to zero . At this point the rate of conversion of liquid into gas and rate of conversion of gas into liquid becomes equal . This is called dynamic equilibrium point .
If we change the temperature , the equilibrium gets disturbed .
At this point the pressure exerted by the gas is called the vapour pressure of the liquid .
So option b ) is correct .