the answer is C
It is a chemical change because heat energy is absorbed and the pack gets colder. A change in temperature is a sign that a chemical reaction has taken place; increase in temperature is an exothermic reaction and decrease in temperature is an endothermic reaction. This is an endothermic chemical reaction.
If he was 30.8% too low, it means that he was at 69.2% of the boiling point needed. So 50o C is 69.2% of total.
In order to know what 100% is, you can divide the number by it's percentage and then multiply it by a hundred.
So: 50/30.8=1.623
1.623*100=162.3
So the correct boiling point of the liquid he was working with in the lab is 162.3 oC
Answer:
2(mass no of magnisium)+mass of barium
plug in the values
Isomers have the same molecular formula but they only differ in structure. So, when trans isomer is converted to cis isomer, you would expect a total mass of 25 mg exactly. So, the percent yield would be:
Percent yield = 5 mg/25 mg * 100 = <em>20%</em>
