Answer: Option (b) is the correct answer.
Explanation:
Since energy of reactants is less than the energy of products. Therefore, it means energy is absorbed during the reaction.
As the energy required to break the bonds in the reactants is greater than the energy released when products are formed.
Therefore, it is an endothermic reaction.
Thus, we can conclude that the statement, it is endothermic because the energy required to break bonds in the reactants is greater than the energy released when the products are formed is correct.
Answer:In the chemical formula Al2(SO4)3, the Al2 means there two aluminium (atoms or ions). The SO4 is a sulfate ion and (SO4)3 means there are 3 sulfate ions. The number 3 before Al2(SO4)3 means there are three times the number of atoms and ions of the chemical formula.
solution:
You need to find the frequency, and they have already given you the wavelength. And since you already know the speed of light, you can use formula (2) to answer this problem. Remember to convert the nano meters to meters because the speed of light is in meters. 
What type of rock is the wave made of?
Answer: The Wave is a natural formation of ~sandstone rocks~
Because 25% is half of 0.5 and the half life of 
is given as 5,715, the time it takes to reach this amount should just be double the half life: 11430 years.
However, in other cases the problem may not have easy numbers, so below is a more mathematical approach.
The half life formula is 
.
Solving for t gives:
Given information:
Plug in given values and solve for t.
With correct significant figures, this would be 11000 years.
