Answer:
Holmium can absorb neutrons, so it is used in nuclear reactors to keep a chain reaction under control. Its alloys are used in some magnets. Holmium has no known biological role, and is non-toxic. Holmium is found as a minor component of the minerals monazite and bastnaesite.
Explanation:
this is basically used in industries
Explanation:
Upon dissolution of KCl heat is generated and temperature of the solution raises.
Therefore, heat generated by dissolving 0.25 moles of KCl will be as follows.

= 4.31 kJ
or, = 4310 J (as 1 kJ = 1000 J)
Mass of solution will be the sum of mass of water and mass of KCl.
Mass of Solution = mass of water + (no. of moles of KCl × molar mass)
= 200 g + 
= 200 g + 13.625 g
= 213.625 g
Relation between heat, mass and change in temperature is as follows.
Q = 
where, C = specific heat of water = 
Therefore, putting the given values into the above formula as follows.
Q = 
4310 J =
Thus, we can conclude that rise in temperature will be
.
Answer:
0.17325 moles per liter per second
Explanation:
For a first order reaction;
in[A] = in[A]o - kt
Where;
[A]= concentration at time t
[A]o = initial concentration
k= rate constant
t= time taken
ln0.5 =ln1 - 2k
2k = ln1 - ln0.5
k= ln1 - ln0.5/2
k= 0 -(0.693)/2
k= 0.693/2
k= 0.3465 s-1
Rate of reaction = k[A]
Rate = 0.3465 s-1 × 0.50 mol/L
Rate = 0.17325 moles per liter per second
Answer:
Molecular Mass:
1. 40g per mole
2. 19g per mole
3. 64g per mole
4. 32 g per mole
5. 17g per mole
6. 59.5g per mole
7.58.5 g per mole
8.220g per mole
9. 78g per mole
10. 200g per mole
Explanation:
Molecular Mass = Number of atom x atomic mass of an element
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