<h2>Answer:</h2>
The mass of the system will remain the same if there is no conversion of mass to energy in the reaction.
<h3>Explanation:</h3>
- If the system is closed, then according to the law of mass conservation the mass of the reaction system will remain the same.
- <u><em>Law of conservation of the mass: In simple words, it is described as the mass of a closed system can never be changed, it may transfer from one form to another or change into energy.</em></u>
- But if the reaction involves energy transfer like heat or light production, in this case, the mass can be changed.
The given dehydration equation is,

Cadmiumnitrate tetrahydrate when heated dehydrates releasing the combined water as water vapor. The reaction produces 4 moles of gaseous product water vapor. So, the degree of disorder or randomness increases. Hence, the sign of change in entropy is positive.
This reaction is spontaneous at room temperature even if it is endothermic as the sign of change in entropy is positive.
Answer: 
Explanation:
Significant figures : The figures in a number which express the value or the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
Rules for significant figures:
Digits from 1 to 9 are always significant and have infinite number of significant figures.
All non-zero numbers are always significant.
All zero’s between integers are always significant.
All zero’s after the decimal point are always significant.
All zero’s preceding the first integers are never significant.
Thus
has three significant figures
0.216g of aluminium compound X react with an excess of water water to produce gas. this gas burn completely in O2 to form H2O and 108cm^3of CO2 only . the volume of CO2 was measured at room temperature and pressure
0.108 / n = 24 / 1
n = 0.0045 mole ( CO2 >>0.0045 mole
0.216 - 0.0045 = 0.2115
so Al = 0.2115 / 27 => 0.0078 mole
C = 0.0045 * 1000 => 4.5 and Al = 0.0078 * 1000 = 7.8
It is b because I'm just going around the house with me to the mall to get u at the moment I don't have any plans tonight or naw