Answer:
2 a
element pure form cannot broken down
3 b
Chemical change chemical R×N
(R×N = reaction)
4c homogeneous solution
Yield = Yield (reaction yield): A measure of a chemical reaction's efficiency, as a ratio of moles of product to moles of reactant. Usually expressed as a percentage. % Yield = Moles of product.
Explanation:
Answer:
D. It is a chemical reaction because the total mass remains the same when new substances are formed.
Explanation:
A chemical reaction is represented by a chemical equation which show the reactant and products. Reactants are written on left side of arrow while products are written on right side. The number of atoms are remain same however arrangement of atoms is different on both side.
For example:
6H₂O + 6CO₂ + energy → C₆H₁₂O₆ + 6O₂
it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen. The number of atoms are same on both side however arrangement of atoms is different.
While in case of nuclear reaction small change in mass take place.
Answer : (C) Hafnium is the most likely identity of the given substance.
Solution : Given,
Mass of given substance (m) = 46.9 g
Volume of given substance (V) = 3.5 
First, find the Density of given substance.
Formula used :
Now,put all the values in this formula, we get
= 13.4 g/
So, we conclude that the density of given substance (13.4 g/) is approximately equal to the density of Mercury and Hafnium (13.53 and 13.31 g/ respectively).
According to the question the substance is solid at room temperature but Mercury is liquid at room temperature. So, Mercury is not identical to the given substance.
Another element i.e, Hafnium is the element whose density is approximately equal to the given substance and also solid at room temperature. And we know that the melting point of solid is high.
So, Hafnium is the most likely element which is the identity of the given substance.
Answer:they have the same number of electrons in the valence shell
Explanation:
Answer:
13.5 %
Explanation:
First we<u> calculate the mass of 500 mL of water</u>, using <em>its density</em>:
- 500 mL * 1.00 g/mL = 500 g
Then we <u>calculate the mass percent of potassium sulfate</u>, using the formula:
Mass of Potassium Sulfate / Total Mass * 100%
- 78 g / (78 + 500) g * 100 % = 13.5 %
