Answer: The atomic mass of these two isotopes is 40.03 amu. The average mass is closer to actual amu of 58.69 for nickel as its percentage abundance is more.
Explanation:
Mass of isotope 1 = 63.93
% abundance of isotope 1 = 0.93% =
Mass of isotope 2 = 57.93
% abundance of isotope 2 = (68.08)% =
Formula used for average atomic mass of an element :
![A= 40.03amu](https://tex.z-dn.net/?f=A%3D%0A40.03amu)
Therefore, the average atomic mass of nickel is, 40.03 amu. The average mass is closer to actual amu of 58.69 for nickel as its percentage abundance is more.
Answer:
When an electron in an atom has absorbed energy it is said to be in an excited state. An excited atom is unstable and tends to rearrange itself to return to its lowest energy state. When this happens, the electrons lose some or all of the excess energy by emitting light.
Explanation:
i looked it up.
Answers are:
1) Carbon-14 is a naturally occurring carbon isotope.
2) Carbon-14 has a known half-life.
3) Carbon-14 is present in all living organisms.
Living things have carbon-14 in their organism, but when they died, the amount of C-14 they contain begins to decrease as the C-14 undergoes radioactive decay. Measuring the amount of C-14 in a sample from a dead plant or animal when the animal or plant died.
The half-life of C-14 is about 5730 years.
Half-life is the time required for a quantity (in this example number of radioactive nuclei of carbon-14) to reduce to half its initial value.
<span>STP means standard temperature
and pressure at 0°C (273K) and 1 atm (atmosphere). The density of the unknown
gas is 0.63 gram per liter. The deal gas equation is PV = nRT. The n is the
numer of moles and can be represented as mass of the gas, m, divided by the
molar mass, c. so we have,</span>
PV = nRT
PV = (m/c)RT
Since the density is d = m/V
Pc = (m/V)RT
Pc = dRT
c = drT/P
substitute the values into the equation,
c = [(0.63g/L)(0.08206
L-atm/mol-K)(273K)]/(1atm)
<u>c = 14.11 g/mol</u>
Solution:
Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol.
Therefore,
Latice Energy: K⁺(g) + NO₃⁻(g) → KNO₃(s) . . . ∆H = –163.8 kcal/mol
Hydration:
K⁺(g) + NO₃⁻(g) + excess H₂O → K⁺(aq) + NO₃⁻(aq) . . . ∆H = –155.5 kcal/mol
Flip the first equation and add them together:
KNO₃(s) + excess H₂O → K⁺(aq) + NO₃⁻(aq) . . . ∆H = +8.3 kcal/mol = +34. 73 kJ/mol
(110kJ)/(34. 73 kJ/mol) = 3.16729 mol must be dissolved to absorb 110 kJ