Answer:- 448 mL of hydrogen gas are formed.
Solution:- It asks to calculate the volume of hydrogen gas formed in milliliters at STP when 0.020 moles of magnesium reacts with excess HCl acid. The balanced equation is:

There is 1:1 mol ratio between Mg and hydrogen gas. So, the moles of hydrogen gas is also equals to the moles of Mg reacted.
moles of Hydrogen gas formed = 0.020 mol
At STP, volume of 1 mol of the gas is 22.4 L. We need to calculate the volume of 0.02 moles of hydrogen gas.

= 0.448 L
They want answer in mL. So, let's convert L to mL using the conversion formula, 1L = 1000mL

= 448 mL
So, 0.020 moles of magnesium would produce 448 mL of hydrogen gas at STP on reacting with excess of HCl acid.
The component of the candle burning in the surrounding has been the oxygen in the air.
The burning of candle wax and wick has been the chemical reaction. It has been based on the reaction of wick with the atmospheric oxygen, resulting in the formulation of the wax burning.
<h3>Chemical reaction of burning of wax</h3>
The wax has been vaporizes by the heat of the flame, that has been resulted by the burning. The wick has been able to react with the oxygen and form the byproducts that helps in flame burning.
The end products have been wick and oxygen as the wax has been consumed in the reaction. The air in the surrounding has oxygen as the part of the system, as it has been involved in the reaction.
Learn more about candle burning, here:
brainly.com/question/25955977
Answer:
The average height of the sunflower sprouts at the end of week 3 is 12.0
cm.
The average height of the birch sprouts at the end of week 3 is 7.2
cm.
Explanation:
they showed it on edgu
Answer: It is (J) Chemical to mechanical
Explanation: And i think its right! Just hope it helps!!