Answer:
c. add coefficients as needed
Explanation:
A chemical equation is defined as the equation that shows changes in a chemical reaction. A chemical equation consist of reactant and product, reactant is at left side of the arrow and product is at right side of the arrow.
Reactant => Product
While balancing a chemical equation, the basic rule is to balance the coefficient as required. Coefficient represents the number of molecules and is used at front of a chemical symbol. Change in coefficient helps balance the number of atoms or molecules of the substances on both the sides of the arrow.
Subscripts are never allowed to change because it can change the chemical involved in the reaction.
Hence, the correct answer is "c. add coefficients as needed".
% composition of ethanol = 34.51%
% composition of water = 65.49%
<h3>What is density?</h3>
A material's density is defined as its mass per unit volume.
Given data:
The density of ethanol = 0.7890 g/mL
The density of water = 0.9982 g/mL
The density of mixture = 0.926 g/mL
Let the % composition of ethanol = x
Let the % composition of water = 100-x
Now density of the mixture



%
Hence,
% composition of ethanol = 34.51%
% composition of water = 65.49%
Learn more about the density here:
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The normality of the H₂SO₄ that reacted with 25cc of 5 % NaOH solution is 1.1 N.
<h3>What is the molarity of 5% NaOH?</h3>
The molarity of 5% NaOH is 1.32 M
25 cc of NaOH neutralized 30cc of H₂SO₄ solution.
Equation of reaction is given below:
- 2 NaOH + H₂SO₄ ---> Na₂SO₄ + 2 H₂O
Molarity of H₂SO₄ = 1.32 x 1 x 25/(30 x 2) = 0.55 M
- Normality = Molarity × moles of H⁺ ions per mole of acid
moles of H⁺ ions per mole of H₂SO₄ = 2
Normality of H₂SO₄ = 0.55 x 2 = 1.1 N
In conclusion, the normality of an acid is determined from the molarity and the moles of H⁺ ions per mole of acid.
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Answer:
C The experiment shows that the red substance experienced a chemical change.
Explanation:
Apparently, adding heat caused the red substance to decompose into a gas and a metallic liquid. If it were simply a phase change, the original red substance could be expected to return when the temperature cooled. Because the substance apparently decomposed, it is clearly not an element. At no point in the experiment is there any evidence of a plasma being formed.
The observed decomposition is a chemical change.
In Homogeneous, "Homo" means same, so homogeneous means the same nature or kind.
Heterogeneous is the opposite. It means diverse.
A good way to remember is just think of homo as same. And the rest should come to you.
Hope this helps! :)