Answer:
[OH⁻] = 4.3 x 10⁻¹¹M in OH⁻ ions.
Explanation:
Assuming the source of the carbonate ion is from a Group IA carbonate salt (e.g.; Na₂CO₃), then 0.115M Na₂CO₃(aq) => 2(0.115)M Na⁺(aq) + 0.115M CO₃²⁻(aq). The 0.115M CO₃²⁻ then reacts with water to give 0.115M carbonic acid; H₂CO₃(aq) in equilibrium with H⁺(aq) and HCO₃⁻(aq) as the 1st ionization step.
Analysis:
H₂CO₃(aq) ⇄ H⁺(aq) + HCO₃⁻(aq); Ka(1) = 4.3 x 10⁻⁷
C(i) 0.115M 0 0
ΔC -x +x +x
C(eq) 0.115M - x x x
≅ 0.115M
Ka(1) = [H⁺(aq)][HCO₃⁻(aq)]/[H₂CO₃(aq)] = [(x)(x)/(0.115)]M = [x²/0.115]M
= 4.3 x 10⁻⁷ => x = [H⁺(aq)]₁ = SqrRt(4.3 x 10⁻⁷ · 0.115)M = 2.32 x 10⁻⁴M in H⁺ ions.
In general, it is assumed that all of the hydronium ion comes from the 1st ionization step as adding 10⁻¹¹ to 10⁻⁷ would be an insignificant change in H⁺ ion concentration. Therefore, using 2.32 x 10⁻⁴M in H⁺ ion concentration, the hydroxide ion concentration is then calculated from
[H⁺][OH⁻] = Kw => [OH⁻] = (1 x 10⁻¹⁴/2.32 x 10⁻⁴)M = 4.3 x 10⁻¹¹M in OH⁻ ions.
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NOTE: The 2.32 x 10⁻⁴M value for [H⁺] is reasonable for carbonic acid solution with pH ≅ 3.5 - 4.0.
Answer: Option (b) is the correct answer.
Explanation:
A synthesis reaction is the reaction in which two compounds or atoms combine together to result in the formation of a single compound.
For example, 
Thus, here CaO and 
combine together to result in the formation of calcium carbonate compound. Therefore, it is a synthesis reaction.
Therefore, we can conclude that the most likely products of Cao + co2 → CaCO3 reaction.
From the periodic table:
mass of carbon = 12 grams
mass of hydrogen = 1 gram
mass of chlorine = 35.5 grams
Therefore,
molar mass of CH2Cl2 = 12 + 2(1) + 2(35.5) = 85 grams
number of moles = mass / molar mass
number of moles of CH2Cl2 = 66.05 / 85 = 0.777 moles
One mole of CH2Cl2 contains two moles of Cl and each chlorine mole has Avogadro's number of atoms in it.
Therefore,
number of chlorine atoms in 0.777 moles of CH2Cl2 can be calculated as follows:
number of atoms = 0.777 * 2 * 6.022 * 10^23 = 9.358 * 10^23 atoms
Now, we will take log base 10 for this number:
log (9.358 * 10^23) = 23.97119
Answer:
25.9g
Explanation:
Molecular mass of Fe₂O₃ = (56 * 2) + (16 * 3)
= 112 + 48 = 160
Let's follow the unitary method now
In 160g Fe₂O₃ , there is 112 g Fe
In 1 g Fe₂O₃ , there is 112 / 160 g Fe
In 37 Fe₂O₃ , we need 112 * 37 / 160
= 25.9 g Fe
Answer:
2RbNO2 + BaCO3 → Rb2CO3 + Ba(NO2)2
Explanation:
The balanced reaction equation is shown below;
2RbNO2 + BaCO3 → Rb2CO3 + Ba(NO2)2
This reaction is possible because the reduction potential of Rb is -2.98V while that of Ba is –2.92 V. Hence Rb can displace Ba from its salt solution.
The equation is balanced since the number of atoms of each element on the left and right hand sides of the reaction equation are equal.
