<h2>Natural Abundance for 10B is 19.60%</h2>
Explanation:
- The natural isotopic abundance of 10B is 19.60%.
- The natural isotopic abundance of 11B is 80.40%.
- The isotopic masses of boron are 10.0129 u and 11.009 u respectively.
For calculation of abundance of both the isotopes -
Supposing it was 50/50, the average mass would be 10.5, so to increase the mass we need a more percentage of 11.
Determining it as an equation -
10x + 11y= 10.8
x+y=1 (ratio)
10x + 10y = 10
By taking the denominator away from the numerator
we get;
y = 0.8
x + y = 1
∴ x = 0.2
To get percentages we need to multiply it by 100
So, the calculated abundance is 80% for 11 B and 20% 10 B.
Missing text find on internet: a<span> 90,0 mL sample of water is heated to its boiling point.
V(H</span>₂O) = 90,0 mL.
d(H₂O) = 1,00 g/mL.
m(H₂O) = 90 mL · 1,00 g/mL.
m(H₂O) = 90 g.
n(H₂O) = m(H₂O) ÷ M(H₂O).
n(H₂O) = 90 g ÷ 18 g/mol.
n(H₂O) = 5 mol.
Q = n(H₂O) · ΔHvap
Q = 5 mol · 40.65 kJ/mol.
Q = 203,250 kJ.
Q - heat reqiured.
only metals above hydrogen
Explanation:
On the activity series, only metals above hydrogen will displace it in solution.
The activity series is a list of metals and non-metals that shows how reactive they are.
- Metals high in the series are highly reactive.
- Those that are down below are less reactive.
- As a rule of thumb, any metal higher than another in the series will displace it from the solution containing the lower metal.
- As with hydrogen, only metals that above it will displace it from solutions.
- Reactions of this kind are called single displacement reactions
learn more:
Chemical reactions brainly.com/question/3953793
#learnwithBrainly
Well protists quite very as organisms i.e it is hard to say if an organism is a protist. Some main features of protists are that they have
1. A membrane enclosed nucleus
2.They are mainly single celled
Also protista are found mainly anywhere water is present for example damp soil, pools and lakes.
Hope this helps :).
Answer : If any atom has more electrons than one energy level can hold, then automatically the electron is accommodated in the next energy level (shell). The remaining extra electrons starts to fill the next energy level. This produces the valency of that particular atom.