A spectrum that includes all colors and doesn't have
any gaps in it is a continuous spectrum.
<u>Answer:</u> The
for the reaction is -1835 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction follows:

The intermediate balanced chemical reaction are:
(1)
( × 4)
(2)

The expression for enthalpy of the reaction follows:
![\Delta H^o_{rxn}=[4\times (-\Delta H_1)]+[1\times \Delta H_2]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B4%5Ctimes%20%28-%5CDelta%20H_1%29%5D%2B%5B1%5Ctimes%20%5CDelta%20H_2%5D)
Putting values in above equation, we get:

Hence, the
for the reaction is -1835 kJ.
Answer: 20) 2365 g
21) 22.39 grams.
22) 29.99 g
Explanation: 20) molarity is the no of moles of solute per unit volume.
We can calculate amount of CaCl2 required to prepare 0.1 M CaCl2 1000 ml solution.
we know that to prepare one ltr of 1 M solution of CaCl2 111 g required
Now consider x gram will require to prepare to
so that comparing above both condition
1000ml ×1M×X g=1000ml×0.1M×111g
X= 11.1 gram
X= 11.1 g of CaCl2
Hence 11.1 g of CaCl2 would be dissolved in 1.0L of a 0.100 M solution of CaCl2
21) How many moles of CaCl₂ in that solution?
;
;
.
What's the mass of that 0.20172 moles of CaCl₂?
Molar mass from a modern periodic table:
Ca- 40.078;
Cl- 35.45.
Molar mass of CaCl₂:
.
Mass of that 0.20172 moles of CaCl₂:
22) its a 3.0m solution so 1 litre of solution contains 3 moles of NaOH, 250ml of solution contains 0.25x39.9971 g/mol, so 250ml of this solution contains 0.75x39.9971=29.99g, or if you round it up 30.0g