You have to be very careful with this question. A change in mass can also occur in chemical changes especially if you have too much of something. For example
CH4 + 1.5 02 ===> CO2 + H2O
If you have too much of either CH4 or O2, there will be some CH4 or O2 left over. There has been a change in mass that you have too much of.
However that is not the point of the question. It is just something you need to be aware of.
Suppose you have a piece of aluminum and you take a course grinder after it. You will change the texture of the side you took the grinder to. If the aluminum has been anodized (a color has been put on it's surface), you may grind the color off or if it is just plain aluminum, you may roughen the surface, but you won't change what the aluminum will do chemically.
You may need only a small portion of the aluminum and you grind off just what you need. That will change the mass of both what you took off and the piece that you want, but the aluminum will still do whatever chemical property you need to use.
So you can change both texture and mass without changing the chemical properties of the substance whose mass or texture you are changing.
Reactants are what is changed in the chemical reaction. They go before the arrow when you wrote the equation. Products are what is formed when the chemical reaction occurs. Products always contain the same elements as the reactants, but they might be rearranged because of the reaction. In this picture, you can see that the reactants go before the arrow, and the products go after.
Answer: It is very important to know the activity tendencies of the elements. The activity tendencies tells us about whether the element is reactive or not.
In the redox-reaction where there is a need to know the oxidizing agent and reducing agent, we can know it easily from the activity tendencies. The elements lying above the reactivity series are better reducing agents.
In the substitution reactions, the activity tendencies helps us to know which element will replace the other. The element lying above in the series will replace the element lying below it.

where, N is an element that lies above in the reactivity series
M is an element that lies below in the reactivity series
Answer:
5.168 L
Explanation:
Applying Charles Law,
V/T = V'/T'..................... Equation 1
Where V = Initial Volume, T = Initial Temperature in Kelvin, V' = Final Volume, T' = Final Temperature in Kelvin,
Make V' the subject of the equation,
V' = VT'/T................. Equation 2
From the question,
Given: V = 5L, T = 25°C = (25+273) = 298K, T' = 35°C = (35+273) = 308K
Substitute these values into equation 2
V' = (5×308)/298
V' = 5.168 L