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.

It take more energy to break the bonds of the reactants and less energy is given off when the product bonds are formed.
<h3>What is Energy?</h3>
Energy is defined as the ability to do work. Work is done in the breaking or formation of bonds.
The standard Enthalpy (ΔH) of water which was formed in the given reaction is negative.
ΔH= Δproduct - Δreactant
This means that the energy to break the bonds of the reactants is more.
Read more about Enthalpy here brainly.com/question/14291557
Answer:
12.18 u
Explanation:
The average atomic mass of an element is calculated by taking the weighted average of the atomic masses of its stable isotopes.
Helloo
To convert to L
2.5 hm^3 * (100m/hm)^3 *1000 L/m^3 gives a volume of 2.5*10^9 L
Have a nice day