A. its only a physical change. It is not a chemical change as no H2O bonds are broken. When water molecules absorb enough energy they are able to change states i.e solid --> liquid , liquid --> vapour.
Hope this is clear
Answer: A. The flask would probably feel cooler than before the reaction started.
Explanation: An endothermic reaction is a type of of chemical reaction in which energy is absorbed from the surroundings. The temperature of the surrounding decreases.
An Exothermic reaction is a type of of chemical reaction in which energy is released into the surrounding. The temperature of the surrounding increases.
When an endothermic reaction takes place in the flask, the heat is absorbed by the flask and thus the temperature of the surrounding (here the flask) will decrease which can be felt by touching the outside of the test tube. Thus the flask would appear colder.
Potassium goes to argon so that a proton in the K nucleus "vanishes" into a positron (positive electron ?) but keeps the same atomic mass at 38. ? I'd say that the number of the positron was 0, and the charge was +1 electronic charge.
exothermic
Explanation:
negative means it's losing energy
P=F/A
A=F/P
P = 0.1 atm = 10132.5 Pa
A=4 x 10⁵/10132.5
A=39.477 m²
for one wing=39.477 : 2 = 19.739 m²