Scientific methods are used to study living things or investigate questions and solve problems.
This problem is asking for the for pH when a solution of potassium hydroxide is diluted to the double of its initial volume. Thus, the answer turns out to be 11.0.
<h3>pH calculations</h3>
In chemistry, pH calculations are performed based on the following equation relating the pH and the concentration of hydrogen ions in the solution:
However, since this problem involves a strong base, KOH as potassium hydroxide, one must calculate the pOH instead, and then convert it to pH with the following equations:
In addition, due to the fact it is diluted from 10. mL to 20. mL (with the 10. mL of added distilled water), one needs to use the dilution equation in order to calculate the correct concentration of KOH:
Hence, the pOH turns out to be:
And thereby the pH:
Learn more about pH calculations: brainly.com/question/1195974
Answer:
To find the number of moles we must first calculate the molar mass( M) of Fe2O3
Molar mass = mass / number of moles
M(Fe2O3) = (55.8 ×2) + (16×3)
= 111.6 + 48
= 159.6 g/mol
number of moles = mass / molar mass
= 125g/159.6g/mol
= 0.783mol
Hope this helps
Mass number (A) =protons (p+) + neutrons(n°)
Answer:
1.14kg of chalcopyrite
Explanation:
In 1 mole of chalcopyrite, CuFeS₂, there is 1 mole of Cu. Thus, to solve this question we need to convert the mass of pure Cu to moles using molar mass (Cu = 63.546g/mol). Then, the moles of Cu are equal to moles of chalcopyrite that must be converted to grams and then to kg (CuFeS₂: 183.54g/mol)
<em>Moles Cu:</em>
395g Cu * (1mol / 63.546g) = 6.216 moles Cu = 6.216 moles CuFeS₂
<em>Mass chalcopyirite:</em>
6.216 moles CuFeS₂ * (183.54g/mol) = 1140.9g
<em>In kilograms:</em>
1140.9g * (1kg / 1000g) =
<h3>1.14kg of chalcopyrite</h3>