1) PV=nRT
P=738.0 mmHg
V=15.5mL=0.0155 L
T=273+25=298 K
R=62.36 L*mmHg*K⁻¹mol⁻¹
n=PV/RT
n=(738.0 mmHg *0.0155 L)/(62.36 L*mmHg*K⁻¹mol⁻¹*298 K)= =0.000616=6.16*10⁻⁴ mol
2) From the equation of the reaction
1 mol CaCO3 gives 1 mol CO2,
so 6.16*10⁻⁴ mol CaCO3 ----> 6.16*10⁻⁴ mol CO2
Molar mass CaCO3 =M(Ca)+M(C)+3*M(O)= 40.1+12.0+3*16.0 =100.1 g/mol
6.16*10⁻⁴ mol CaCO3 * 100.1 g/mol =617*10⁻⁴ g =0.0617 g = 61.7mg
We want to write the nuclear equation for the beta decay of Aluminium-25.
The equation is:

First, as you may know, in a beta decay the number of protons is increased by one. Aluminium has 13 of them, so after the decay, we will have 14 protons.
This means that the aluminium will transform into silicon, then the nuclear equation is just:

Where the:

Is an electron, which is the emitted particle in the beta decay.
If you want to learn more, you can read:
brainly.com/question/4184205
The elements are arranged in horizontal rows, or periods, by order of increasing atomic number, which equals the number of protons in the atomic nucleus of each element.
Answer:
5.47 x 10^23 atoms in Ag (sliver)
Explanation:
0.909 mol of Ag x 6.02 x 10^23 atoms of Ag/ 1 mol of Ag