Answer:
<em>Mg = 24.30 g/mol) Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g) Hint: 1 mole of gas at STP occupies 22.4 L</em>
<u>Answer:</u> The expression of
is written below.
<u>Explanation:</u>
We are given a chemical compound which is trimethylamine that acts as a weak base when dissolved in water.
It accepts a proton from the water to form trimethylammonium ion and hydroxide ion.
The chemical equation for the reaction of trimethylamine in water follows:

The expression of
for above equation follows:
![K_b=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}](https://tex.z-dn.net/?f=K_b%3D%5Cfrac%7B%5B%28CH_3%29_3NH%5E%2B%5D%5BOH%5E-%5D%7D%7B%5B%28CH_3%29_3N%5D%7D)
Hence, the expression of
is written above.
The number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
<h3>What is significant figures?</h3>
Significant figures of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something.
Also significant figures can be defined as, the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.
Examples of significant figures;
- 405 = 3 significant figures
- 405000 = 3 significant
- 0.040500 = 5 significant figures
<u>Note:</u> leading zeros are not significant but trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point.
345,000 = 3.45 x 10⁵ (3 significant figures)
Thus, the number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
Learn more about significant figures here: brainly.com/question/24491627
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Answer : The original volume of gas was, 3.0 L
Explanation :
Charles' Law : It is defined as the volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

or,

where,
are the initial volume and temperature of the gas.
are the final volume and temperature of the gas.
We are given:

Now put all the given values in above equation, we get:

Thus, the original volume of gas was, 3.0 L