Answer:
a) I believe it has a volume of 25 ml. I found the value by subtracting 40 from 65.
Hope this Helps!
<em>-kiniwih426</em>
Friedrich Mohs devised a scale that tested mineral <span>hardness, </span>which means the resistance of a mineral to being scratched. This scale (from 1 to 10) is known as the Mohs Hardness Test. Objects are used as tools to perform the hardness test:
<span>fingernail (hardness = 2,5).
copper penny (hardness = 3)
glass plate or steel knife (hardness = 5,5)
<span>steel file (hardness = 6,5).
According to this scale </span></span><span>hardness of the mineral is between 5,5 and 6,5.</span>
<h3>
Answer:</h3>
C. A change in concentration results in a change in the rate of a
reaction
<h3>
Explanation:</h3>
We first need to know what is the rate of a reaction;
- The rate of a reaction refers to the speed at which reactants are converted to products.
Secondly we need to identify several factors that affect the rate of reactions.
- The rate of reactions depends on a number of factors which include, surface area of reactants, concentration of both reactants and products, temperature, presence of a catalyst, etc.
Thirdly, understand the effect of concentration of reactants and products on the rate of reaction.
- If we consider the concentration of reactants and products;
- An increase in the concentration of reactants increases the number of collisions which results to an increase in the rate of reaction.
- On the other hand, when the concentration of products is increased, the rate of reverse reactions increases for reversible reactions while a decrease in the concentration of reactants favors forward reaction.
Therefore, in our case, we can say that, a change in the concentration of either reactants or products results in a change in the rate of a reaction.
Answer: D) An Mg atom donates one electron to each of the two Cl atoms.
Explanation: Ionic compound is formed by transfer of electrons from metal to non metal.
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here magnesium is metal with atomic number 12 and chlorine is a non metal with atomic number of 17.
Thus magnesium loses two electrons to form 
and chlorine atoms gain one electron each to form 
Thus the compound formed is 
.
