Answer:
Chemicals A and B form an endothermic reaction, and chemicals C and D form an exothermic reaction.
Explanation:
The reaction that produced chemical C is an endothermic reaction whereas, the reaction between C and D is an exothermic one.
An exothermic change is one in which heat is liberated to the surroundings. So the surrounding becomes hotter at the end of the reaction.
An endothermic reaction is a change in which heat is absorbed from the surrounding and hence the surrounding colder at the end of the change.
- We can see that the first reaction is endothermic.
- The second reaction is exothermic.
Explanation:
From the source, The student recrystallized biphenyl by using benzene. Biphenyl is non polar and so is benzene. Biphenyl is very soluble in benzene at low as well as high temperature. Thus, it do not recrystallize as like dissolves like and gives a very poor yield.
The good recovery of the product is dependent on compound having high solubility at the high temperatures and having low solubility at the low temperatures.
First we need to find the number of moles of both K and O reacted
K - 0.779 g / 39 g/mol
= 0.02 mol
the mass of O₂ reacted = 1.417 g - 0.779 g = 0.638 g
O₂ moles = 0.638 g / 32 g/mol
= 0.02 mol
the number of both K and O₂ moles reacted are equal
therefore stoichiometry of K to O₂ reacted are 1:1
then the formula of potassium superoxide is KO₂
I don't understand what is (g).
Maybe the answer is 2H<span>(aq)S</span>₂<span>−2(aq) </span>⇒ <span>H</span>₂<span>S</span>₂.
To most geologists, the term "acid test" means placing a drop of dilute (5% to 10%) hydrochloric acid on a rock or mineral and watching for bubbles of carbon<span> dioxide gas to be released. The bubbles signal the presence of carbonate minerals such as</span>calcite<span>, </span>dolomite<span>, or one of the minerals listed in Table 1.</span>
