Answer : The value of rate constant is, 
Explanation :
First we have to calculate the rate constant, we use the formula :
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = ?
t = time passed by the sample = 4.84 s
a = initial concentration = 4.17 M
a - x = concentration after time 4.84 s = 3.56 M
Now put all the given values in above equation, we get


Therefore, the value of rate constant is, 
It is endothermic because heat energy is supplied to make the water of crystallization evaporate and make the compound anhydrous.
Answer:
are calculated by multiplying useful energy by the total amount of energy
Explanation:
The energy conversions are never 100 percent efficient. This is because the energy originally is converted into a mixture of the useful and not useful energy. For example, gasoline in the car is converted to motion, sound and friction. The later two (sound and friction) are energies but are less useful. Thus, in this case, the energy conversion is not 100 % efficient. Thus, the energy efficiency equation comes into play. This is given as the ratio of the useful energy to the total energy. It is a fraction.
Rising air in the tropics is called the Intertropical convergence zone and is a region of rising hot air. As it rises, the moisture in the air eventually reaches its saturation point and the moisture falls out as rain. This is why the tropics are know for their very heavy rainfall periods
The phrase that describes the energy of collision is D. kinetic energy transferred when billiard balls hit each other.
<h3>What is collision?</h3>
collision can be regarded as coming together of one solid or direct impact to the other such as car collided with a tree.
Therefore, kinetic energy transferred when billiard balls hit each other is an example.
Learn more about collision at;
brainly.com/question/11352260