The complete question;
Match each type of titration to its pH at the equivalence point.
Weak acid, strong base
Strong acid, strong base
Weak base, strong acid
pH less than 7
pH equal to 7
<span>pH greater than 7
</span>Answer:
weak acid, strong base - pH greater than 7
Strong acid, strong base - pH equal to 7
Weak base, strong acid - pH less than 7
Strong acids dissociate completely to give out H⁺ ions.
Strong bases dissociate completely to give out OH⁻ ions.
When strong acids and strong bases are mixed the dissociated H⁺ and OH⁻ ions react and neutralise each other, making the solution neutral.
Weak acids cannot completely dissociate, only a fraction of H⁺ ions are dissociated. Same applies for weak bases.
When weak acid and strong base is mixed, whilst the strong acid completely dissociates, weak base only partially dissociates. Therefore the amount of H⁺ ions is greater than OH⁻ ions, overall pH is more acidic, hence less than 7.
When strong base and weak acid are mixed, strong base completely dissociates giving OH⁻ ions and weak acid only partially dissociates, therefore amount of OH⁻ ions is greater than H⁺ ions, more basic hence pH is greater than 7.
Answer:
Empirical Formula = C₁H₄ or CH₄
Explanation:
Data Given:
Mass of C = 12.0 g
Mass of H = 4 g
Step 1: <u>Calculate Moles of each Element;</u>
Moles of C = Mass of C ÷ At.Mass of C
Moles of C = 12.0 ÷ 12.0
Moles of C = 1.0 mol
Moles of H = Mass of H ÷ At.Mass of H
Moles of H = 4.0 ÷ 1.0
Moles of H = 4.0 mol
Moles of O = %O ÷ At.Mass of O
Moles of O = 53.924 ÷ 16.0
Moles of O = 3.370 mol
Step 2: <u>Find out mole ratio and simplify it;</u>
C H
1.0 4.0
1.0/1.0 4.0/1.0
1 4
Hence,
Empirical Formula = C₁H₄ or CH₄
Answer:
Magnesium
Explanation:
The element that could provide one atom to make an ionic bond with oxygen is magnesium.
Generally, most group II elements will form an ionic bond with oxygen with just one atom.
An ionic bond forms by the transfer of electrons from one specie to another.
Oxygen has a charge of 2-, to use one atom to form ionic bond with this specie, a magnesium atom with 2+ charge will bond with the specie.
This will form:
MgO
This is notable for other group II elements.
The atomic mass of element B is 106.1 amu.
Given:
- The atomic mass of element A is 35.45 amu.
- A +B → AB
- 28.54 g sample of A combines with 85.42 g of another element B
To find:
The atomic mass of element B.
Solution:
The mass of element A = 28.54 g
The atomic mass of element A = 35.45 amu = 35.45 g/mol
Moles of element A :
= 
A +B → AB
According to reaction, one mole of A combines with 1 mole of B , then 0.8051 moles of A will combine with:
Moles of B element = 0.8051 mol
Mass of element B used = 85.42 g
The atomic mass of element B =M
The atomic mass of element B is 106.1 amu.
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