Answer: Option (b) is the correct answer.
Explanation:
According to the law of conservation of energy, it is known that energy can neither be created nor it can be destroyed.
But energy can be changed from one form to another.
Whereas entropy is the degree of randomness present within the molecules of a substance or object.
For example, gas molecules are able to move rapidly so, they have more entropy as compared to solid and liquid substances.
According to second law of thermodynamics, entropy of the system is always increasing.
Thus, we can conclude that "Conservation of energy" refers to the fact that energy cannot be created or destroyed but can be converted from one form to another.
8.3mL
Explanation:
Given parameters:
Mass of acetone = 6.54g
Density of acetone = 0.7857 g/mL
Unknown:
Volume of acetone = ?
Solution:
Density is defined as the mass per unit volume of a substance. It is expressed mathematically as shown below:
Density = 
Since the unknown is volume, we make it the subject of the formula
Volume = 
Input the values;
Volume = 
= 8.3mL
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Based on the chemical equation, to balance the equation we use 2 as a coefficients of HCl on left hand side of reaction.
<h3>What is balanced equation?</h3>
Balanced chemical equations are those equation in which each entities are present in same amount on left side as well as on the right side of the chemical reaction.
Given chemical reaction is:
Zn + HCl → ZnCl₂ + H₂
Above reaction is not balanced equation as number of chlorine and hydrogen atoms are not same, so balanced equation will be:
Zn + 2HCl → ZnCl₂ + H₂
Hence we add 2 as a coefficient of HCl to balance the equation.
To know more about balance equation, visit the below link:
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They have hydrogens numbers wrong its 1.008 not 1.01
The number of moles in monochloro pentaborane (9) 
is 0.37056.
We know that ,
Number of moles = Given mass/ Molar mass
Given mass of monochloro pentaborane (9) is 20.1 g
The molar mass of monochloro pentaborane (9) is
= 
= 
= 54.241
Thus number of moles = 20.1/54.241
= 0.37056
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