Answer:
The answer is option 3.
Step-by-step explanation:
You have to substitute H+=2×10^(-9) into the equation of pH :
pH = -log[H+]
H+ = 2×10^(-9)
pH = -log[2×10^-9]
= 8.70 (3s.f)
Answer:
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Step-by-step explanation:thjkkmnb
You can check khan academy for help I’m sorry I don’t exactly know :(
<h3>Given</h3>
- Set A: A = {-26, -25, -24, -23, - 22, - 21}
- Set B: B ∈ {x: x is even, x ≥ 6 and x ≤ 20}
<h3>(a) </h3>
<em />
<em>Cardinality means the number of elements in the set.</em>
Cardinality of the set A:
n(A) = 6, since we can count 6 elements.
Set B has even numbers between 6 and 20, both included:
- B = {6, 8, 10, 12, 14, 16, 18, 20}
Then its cardinality is:
<h3>(b) </h3>
To solve this we need to compare the elements of sets A or B with numbers given:
- -22 ∈ A, True ⇒ -22 is listed as element of A
- 6 ∈ B, True ⇒ 6 is listed as element of B
- - 21 ∉ A, False ⇒ - 21 is listed as element of A
- 2 ∈ B, False ⇒ 2 is not listed as element of B
