Answer:

Explanation:
There are two main kinds of properties: chemical and physical.
Chemical properties, like the name suggests, have to be observed by changing the chemical composition.
That leaves <u>physical properties.</u> They can be measured without any chemical composition changes.
Some examples include: color, odor, mass, density, and volume. All can be measured with just the senses or measuring tools and no composition alterations are needed.
Answer:
9.25
Explanation:
Let first find the moles of
and 
number of moles of
= 0.40 mol/L × 200 × 10⁻³L
= 0.08 mole
number of moles of
= 0.80 mol/L × 50 × 10⁻³L
= 0.04 mole
The equation for the reaction is expressed as:

The ICE Table is shown below as follows:

Initial (M) 0.08 0.04 0
Change (M) - 0.04 -0.04 + 0.04
Equilibrium (M) 0.04 0 0.04







for buffer solutions
since they are in the same solution


They'd observe any new substances or new color, and temp. that is irreversible.
If this helped and you have any other questions, feel free to comment on my wall. Hope this helped.
Mass......................
The Law of Conservation of Mass states that the mass of reactants entering a reaction must be equal to the mass of the products exiting it. In this case, we only have 2 reactants, Fe and S, and we only have 1 product, FeS. Therefore we expect the total mass of the Fe and S reactants to equal the mass of FeS. This gives us 112 g + 64 g = 176 g of FeS, which is choice D.