Answer:
See Explanation
Explanation:
An endothermic reaction is one in which energy is absorbed and the change in enthalpy for the reaction is positive.
If we look at the reaction 2HgO + 45kcal ----> 2Hg + O2; we will notice that
i) 45kcal of energy was taken in (absorbed) for the reaction to occur
ii) The value of the reaction enthalpy is positive
For these two reasons, the reaction is an endothermic reaction as written.
Answer:
The right answer is "3 g".
Explanation:
Given:
Initial mass substance,

By using the relation between half lives and amount of substances will be:
⇒ 


Thus, the above is the correct answer.
Answer:
D. It is converted into kinetic energy.
Explanation:
When a book is dropped from a desk to the floor, the potential energy of the book is converted to kinetic energy as it falls.
- Potential energy of a body is the energy due to the position of the body.
- At a particular height, the potential energy is maximum.
- A body with mass and moving with velocity will have kinetic energy
- As the book drops through the height, to conserve energy, the potential energy is converted to kinetic energy.
Answer:

Explanation:
In this case, we can start with the reaction:

If we check the reaction, we will have 2 X and Y atoms on both sides. So, <u>the reaction is balanced</u>. Now, the problem give to us two amounts of reagents. Therefore, we have to find the <u>limiting reagent</u>. The first step then is to find the moles of each compound using the <u>molar mass</u>:


Now, we can <u>divide by the coefficient</u> of each compound (given by the balanced reaction):


The smallest value is for "X", therefore this is our <u>limiting reagent</u>. Now, if we use the <u>molar ratio</u> between "X" and "XY" we can calculate the moles of XY, so:

Finally, with the molar mass of "XY" we can calculate the grams. Now, we know that 1 mol X = 85 g X and 1 mol
= 48 g
(therefore 1 mol Y = 24 g Y). With this in mind the <u>molar mass of XY</u> would be 85+24 = 109 g/mol. With this in mind:

I hope it helps!
I mole is the answer I believe