Answer:- The natural abundance of 
is 0.478 or 47.8% and 
is 0.522 or 52.2% .
Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:
Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)
We have been given with atomic masses for and as 150.919860 and 152.921243 amu, respectively. Average atomic mass of Eu is 151.964 amu.
Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of as n then the abundance of would be 1-n .
Let's plug in the values in the formula:
151.964=150.919860n+152.921243-152.921243n
on keeping similar terms on same side:
negative sign is on both sides so it is canceled:
The abundance of is 0.478 which is 47.8%.
The abundance of is = 
= 0.522 which is 52.2%
Hence, the natural abundance of is 0.478 or 47.8% and is 0.522 or 52.2% .
Answer:
1.90 atm
Explanation:
Using ideal gas equation as:
where,
P is the pressure
V is the volume
n is the number of moles
T is the temperature
R is Gas constant having value = 0.0821 L atm/ K mol
According to above equation, at constant Volume and number of moles, pressure is directly proportional to the temperature. So,
Given ,
P₁ = 1.51 atm
P₂ = ?
T₁ = 23 °C
T₂ = 100 °C ( boiling point of water )
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (23 + 273.15) K = 296.15 K
T₂ = (100 + 273.15) K = 373.15 K
Using above equation as:
<u>New Pressure = 1.90 atm</u>
Answer:
3.5 mol
Explanation:
Step 1: Given data
Moles of HCl: 7.0 mol
Step 2: Write the balanced equation
Fe(s) + 2 HCl(aq) ⇒ FeCl₂(aq) + H₂(g)
Step 3: Calculate the moles of H₂ gas produced from 7.0 moles of HCl
According to the balanced equation, the molar ratio of HCl to H₂ is 2:1.
7.0 mol HCl × 1 mol H₂/2 mol HCl = 3.5 mol H₂
When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.
