Answer:
pH = 12.7
Explanation:
First, we have to calculate the [Ca²⁺] in a solution of about 250 ppm CaCO₃.
Now, let's consider the dissolution of Ca(OH)₂ in water.
Ca(OH)₂(s) ⇄ Ca²⁺(aq) + 2 OH⁻(aq)
The solubility product Ksp is:
Ksp = [Ca²⁺] × [OH⁻]²
[OH⁻] = √(Ksp/[Ca²⁺]) = √(6.5 × 10⁻⁶/2.5 × 10⁻³) = 5.1 × 10⁻² M
Finally, we can calculate pOH and pH.
pOH = -log [OH⁻] = -log (5.1 × 10⁻²) = 1.3
pH + pOH = 14 ⇒ pH = 14 - pOH = 14 - 1.3 = 12.7
Answer:
5.90x10²² atoms of gold are present in the cube
Explanation:
First, we must find the volume of the cube in cm³. With density we can find the mass of the gold and the moles using its molar mass. As 1 mol = 6.022x10²³ atoms we can find the number of atoms:
<em>Volume in cm³:</em>
(10.0mm)³ = 1000mm³
<em>1mm³ = 0.001cm³</em>
1000mm³ * (0.001cm³ / 1mm³) = 1cm³
<em>Mass gold:</em>
1cm³ * (19.3g/cm³) = 19.3g Gold
<em>Moles Gold:</em>
19.3g * (1mol / 197.0g) = 0.0980 moles Gold
<em>Atoms gold:</em>
0.0980 moles Gold * (6.022x10²³ atoms / mol) =
<h3>5.90x10²² atoms of gold are present in the cube</h3>
Answer:
A tundra has a lower average temperatures year-round.
The maximum mass of B₄C that can be formed from 2.00 moles of boron (III) oxide is 55.25 grams.
<h3>What is the stoichiometry?</h3>
Stoichiometry of the reaction gives idea about the relative amount of moles of reactants and products present in the given chemical reaction.
Given chemical reaction is:
2B₂O₃ + 7C → B₄C + 6CO
From the stoichiometry of the reaction, it is clear that:
2 moles of B₂O₃ = produces 1 mole of B₄C
Now mass of B₄C will be calculated by using the below equation:
W = (n)(M), where
- n = moles = 1 mole
- M = molar mass = 55.25 g/mole
W = (1)(55.25) = 55.25 g
Hence required mass of B₄C is 55.25 grams.
To know more about stoichiometry, visit the below link:
brainly.com/question/25829169
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