Explanation:
The reaction equation will be as follows.

Using bond energies, expression for calculating the value of
is as follows.

On reactant side, from
number of bonds are as follows.
C-C bonds = 1
C-H bonds = 6
From
; Cl-Cl bonds = 1
On product side, from
number of bonds are as follows.
C-C bonds = 1
C-H bonds = 5
C-Cl bonds = 1
From HCl; H-Cl bonds = 1
Hence, using the bond energies we will calculate the enthalpy of reaction as follows.

=
= -102 kJ/mol
Thus, we can conclude that change in enthalpy for the given reaction is -102 kJ/mol.
Answer:
An element is a substance that is made up of the same kind of atoms and
cannot be broken down into simpler substances by any known chemical means
examples of element are iron boron carbon helium calcium hydrogen etc
Answer:
Sn₃(PO₄)₄ - tin(IV) phosphate.
Explanation:
Hope it helps! :)
Answer: C) 330 g
Explanation: Since all the masses are given in different units, it's good to make all of them to have same unit. Let's say we convert all of them to grams.
A) kg stands for kilogram and 1 kg = 1000 g
So, 
= 33 g
B) hg stands for hactogram and 1 hg = 100 g
So, 
= 33 g
C) 330 g
D) cg stands for centigram and 1 cg = 0.01 g
So, 
= 33 g
Looking at all the choices, choice A, B and D represent equal amount of matter that is 33 g where as choice C represents 330 g of matter.
Hence, the correct choice is C) 330 g.
Answer:
18 DAYS IS THE HALF LIFE OF THE RADIOISOTOPE.
Explanation:
Using the formula
Nt = No * (1/2)^t/t1/2
where;
Nt = amount remaining = 25 g
No = Initial amounrt of the radioisotope = 50 g
t = time elapsed = 18 days
t1/2 = half life = unknown
Substitute the values into the equation and obtain the half life of the radioisotope;
Nt = No * (1/2) ^t/t1/2
25 = 50 * (1/2) ^18/t1/2
25 /50 = (1/2)^18/ t1/2
1/2 = (1/2)^18/t1/2
1/2)^1 = (1/2)^18/t1/2
1 = 18/t1/2
t1/2 = 18 days.
So therefore the half life of the radioisotope is 18 days.