Answer:
The atomic radius of strontium is larger than magnesium because there are more number of shielding electrones in strontium than magnesium, which causes electron-electron repulsion, that makes the electrons in valance shell to expand. Hence it would decrease the effective nuclear charge.
You divide 19 centimeters by 2.54 making 19 centimeters equivalent to 7.48 inches
<h2>Answer:</h2>
Option (B):
The products can form reactants, and the reactants can form products.
<h3>Explanation:</h3><h3>Reversible reaction</h3>
A reversible reaction is a reaction where the reactants form products, which react together to give the reactants back.
aA + bB ⇄ cC + dD
A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B.
Other options are wrong because off:
(A) Concentration changes with time equilibrium concentration and higher product concentration is also possible.
(C) They may be constant.
(D) Concentration changes with time equilibrium concentration and higher reactant concentration is also possible.
Answer:- 0.800 moles of the gas were collected.
Solution:- Volume, temperature and pressure is given for the gas and asks to calculate the moles of the gas.
It is an ideal gas law based problem. Ideal gas law equation is used to solve this. The equation is:
PV=nRT
Since it asks to calculate the moles that is n, so let's rearrange this for n:

V = 19.4 L
T = 17 + 273 = 290 K
P = 746 mmHg
we need to convert the pressure from mmHg to atm and for this we divide by 760 since, 1 atm = 760 mmHg

P = 0.982 atm
R = 
Let's plug in the values in the equation to get the moles.

n = 0.800 moles
So, 0.800 moles of the gas were collected.