Answer:
Mass = 2.355 g
Explanation:
Given data:
Mass of K₂O needed = ?
Mass of KNO₃ produced = 5.00 g
Solution:
Chemical equation:
K₂O + Ca(NO₃)₂ → CaO + 2KNO₃
Number of moles of KNO₃:
Number of moles = mass/molar mass
Number of moles = 5.00 g/ 101.1 g/mol
Number of moles = 0.05 mol
now we will compare the moles of KNO₃ and K₂O.
KNO₃ : K₂O
2 : 1
0.05 : 1/2×0.05 = 0.025 mol
Mass of potassium oxide needed in gram:
Mass = number of moles × molar mass
Mass = 0.025 mol × 94.2 g/mol
Mass = 2.355 g
Answer:
a
Explanation:
because titration by definition, is used to determine the concentration of one reactant in an aqueous solution, it requires a burette to accurately measure the volume of a solution and endpoints in acid-base titration can be determined by a colour indicator or a pH meter
The oxidation number of chromium (Cr) in CrO₂, Cr₂O₇²⁻ and Cr₂(SO₄)₃³⁻ is +4, +6 and +1.5 respectively.
<h3>What is oxidation number?</h3>
Oxidation number of any compound gives idea about the number of exchangeable electrons from the outer most shell of an atom.
Let the oxidation state of chromium is x and charge on the whole molecule is zero, so it will be calculated as:
x + 2(-2) = 0
x - 4 = 0
x = +4
Let the oxidation state of chromium is x and charge on the whole molecule is -2, so it will be calculated as:
2x + 7(-2) = -2
2x - 14 = -2
2x = 12
x = +6
Let the oxidation state of chromium is x and charge on the whole molecule is -3, so it will be calculated as:
2x + 3(-2) = -3
2x - 6 = -3
2x = 3
x = +1.5 (which is impossible)
Hence oxidation state of chromium atom in CrO₂, Cr₂O₇²⁻ and Cr₂(SO₄)₃³⁻ is +4, +6 and +1.5 respectively.
To know more about oxidation state, visit the below link:
brainly.com/question/8990767
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Answer:
D.
Explanation:
If a compound is composed of oppositely charged ions, it has to be formed by metal and non-metal.
Li2O
Li - metal
O - non-metal