Answer:
<em>The correct option is B) two liquids are mixed at room temperature and a gas forms.</em>
Explanation:
A chemical change can be described as a change which results in the formation of a new substance by the reactants. In the option B, two liquids react to form a new product which is a gas. Hence, it is an example of chemical change.
Other options,like option D, is not a chemical change as by crushing a solid no new product is formed. Option C is also not correct because as when salt dissolves in water, no new product is made.
<h3>
Answer:</h3>
B. C7H16 + 11O2 → 7CO2 + 8H2O
<h3>
Explanation:</h3>
- In a balanced chemical equation, the number of atoms of each element is equal on both sides of the equation.
- In this case, the balanced chemical equation is;
C7H16 + 11O2 → 7CO2 + 8H2O
Because, it has 7 carbon atoms, 16 hydrogen atoms and 22 oxygen atoms on each side of the equation.
- When an equation is balanced it obeys the law of conservation of mass such that the mass of reactants will be equal to the mass of products.
Answer: acid dissociation constant Ka= 2.00×10^-7
Explanation:
For the reaction
HA + H20. ----> H3O+ A-
Initially: C. 0. 0
After : C-Cx. Cx. Cx
Ka= [H3O+][A-]/[HA]
Ka= Cx × Cx/C-Cx
Ka= C²X²/C(1-x)
Ka= Cx²/1-x
Where x is degree of dissociation = 0.1% = 0.001 and c is the concentration =0.2
Ka= 0.2(0.001²)/(1-0.001)
Ka= 2.00×10^-7
Therefore the dissociation constant is
2.00×10^-7
