We have that all (ideal) gases obey the fundamental gas equation: PV=nRT where P is the Pressure, V is the Volume, n is the number of moles, R is a universal constant and T is the temperature in Kelvin. In this process, we have that both the number of moles and the temperature stays the same. So if we denote by i the initial conditions and by f the final conditions of the gas, we have:

. Hence, if we solve for the final Volume we get:

. Now we know all the other variables; substituting we get that the final volume is 6.7 L (6.716 L ).
Choice A because the amount of Joules on both sides are equal to one another (balanced).
Part 1 : Answer is only B substance is soluble in water.
In this experiment undissolved mass of each substance was measured. According to the given data, undissolved mass of substance B at 20 °C is 10 g while A is 50 g. Since, the initial added mass of each substance is 50 g, we can see that substance A is not soluble in water since the undissolved mass is 50 g.
Part 2 : Substance A is not soluble in water and substance B is soluble in water.
According to the given data, the undissolved mass of substance A remains as same as initial added mass, 50 g throughout the temperature range from 20 ° to 80 °C. Hence, we can conclude that substance A is not soluble in water.
But, according to the data, undissolved mass of substance B at 20 °C is 10 g. That means, 40 g of substance B was dissolved in water. When the temperature increases the undissolved mass of substance B decreases. Hence, we can conclude that substance B is soluble in water and solubility increases with temperature.
Answer:
The branch of chemistry that best describes the chemist´s work is organic chemestry
Explanation:
The chemist wants to improve the process for natural gas, a mix of organic compuond, mainly alcans.
1. Endothermic reaction
2. Exothermic reaction
3. Exothermic reaction
<u>Explanation:</u>
1. Evaporation of alcohol from the skin, here the heat is absorbed by the alcohol so that it gets evaporated from the skin and it is an endothermic process. As the reaction says that, the energy is added to the system, so it is endothermic.
C₃H₈O + 5.2 kJ → C₃H₈O(g)
2. Burning of propane in a gas grill:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O + 1652 kJ.
Here energy is released or given out which is termed as exothermic reaction.
3. Oxidation of iron to form rust:
4 Fe + 3O₂ → 2 Fe₂O₃ + 2221 kJ.
Here also energy is released along with the products, so it is termed as exothermic reaction.
Whenever energy is absorbed, the reaction is endothermic in contrast if the energy is released then the reaction is exothermic.