Answer:
0.106 mol (3s.f.)
Explanation:
To find the number of moles, divide the mass of glucose (in grams) by its Mr. Glucose has a chemical formula of C6H12O6. To find the Mr, add all the Ar of all the atoms in C6H12O6.
Ar of C= 12, Ar of H= 1, Mr of O= 16
These Ar values can be found on the periodic table.
Mr of glucose= 6(12)+ 12(1) + 6(16)= 180
Moles of glucose
= mass ÷ mr
= 19.1 ÷ 180
= 0.106 mol (3 s.f.)
Answer:
A
Explanation:
Element A has 3 electrons in outermost shell so its valency is 3. It will loose 3 electrons to attain stability, as loss of 3 electrons is easier than gain of 5 electrons.
Valency of B is −2 as it will gain 2 electrons to attain stability and combine with other atom.
Valency of A⟶+3
Valency of B⟶−2
(Refer to Image)
Cross multiply valency of A and B
∴A2B3 compound will be formed.
The pH of a solution that has a H⁺ ion concentration is 0.0039M is 2.4.
<h3>What is pH?</h3>
pH of any solution gives idea about the acidity or basicity of solution and it will be calculated as:
pH = -log[H⁺]
Given that, concentration of H⁺ ion = 0.0039 M
On putting tis value in pH equation, we get
pH = -log(0.0039)
pH = -(-2.4) = 2.4
Hence required value of pH is 2.4.
To know more about pH, visit the below link:
brainly.com/question/24595796
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When a substance dissociates into OH- ions, they are classified as bases.
