Answer: The pure metal has low structural strength, magnesium is mainly used in the form of alloys- principally with 10% or less of aluminum, zinc, and manganese- to improve it's hardness, tensile strength, and ability to be cast, welded, and machined.
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Answer is (b) , because a chemical change happened
Answer:
[Au] = 0.171 M
Explanation:
For this question, we assume the rock is 100 % gold.
First of all, we determine the moles of gold
67.3 g . 1mol/ 196.97g = 0.342 moles
Molar concentration is defined as the moles of solute, contained in 1L of solution.
Our solution volume is 2L.
M = 0.342 mol / 2L = 0.171
Molar concentration, also called molarity of solution is the most typical unit of concentration.
17, to be neutral it has to have equal number of protons and electrons
Answer:
Explanation:
CH₃CHOHCOOH ⇄ CH₃CHOHCOO⁻ + H⁺
ionisation constant = 1.36 x 10⁻⁴ .
molecular weight of lactic acid = 90 g
moles of acid used = 20 / 90
= .2222
it is dissolved in one litre so molar concentration of lactic acid formed
C = .2222M
Let n be the fraction of moles ionised
CH₃CHOHCOOH ⇄ CH₃CHOHCOO⁻ + H⁺
C - nC nC nC
By definition of ionisation constant Ka
Ka = nC x nC / C - nC
= n²C ( neglecting n in the denominator )
n² x .2222 = 1.36 x 10⁻⁴
n = 2.47 x 10⁻²
nC = 2.47 x 10⁻² x .2222
= 5.5 x 10⁻³
So concentration of hydrogen or hydronium ion = 5.5 x 10⁻³ g ion per litre .
