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.
Answer:
From n=1 to n=2
Explanation:
Electrons in n=1 are strongly attracted to the nucleus and therefore will require great force to overcome the electrostatic force of attraction to displace them from the energy level to another.
The electrostatic force reduces as you progress to the outer energy levels.
A. conduction
that is the correct answer
Answer:
Explanation:
the strength and vitality required for sustained physical or mental activity.
Answer:
The rate at which sulfur dioxide is being produced is 0.90 kg/s.
Explanation:
Volume of oxygen gas consumed in second ,V= 994 L
Pressure of the gas = p
Temperature of the gas = T = 170°C= 170 + 273 K=443 K
Moles of oxygen gas consumed in a second = n
( ideapl gas equation)

n = 21.044 mole
Moles of dioxygen gas consumed per second = 21.044 mol
(Claus process)
According to reaction, 3 moles of dioxygen gives 2 moles of sulfur dioxide gas.Then 21.044 moles of dioxygen will give;
of sulfur dioxide
Mass of 14.029 moles of sulfur dioxide gas;
14.029 mol × 64 g/mol = 897.86 g
897.86 g = 0.89786 kg ≈ 0.90 kg
Mass of sulfur dioxide produced per second = 0.90 kg
The rate at which sulfur dioxide is being produced is 0.90 kg/s.