Answer:
1. [OH⁻] = 0.30 M ; 2. [OH⁻] = 1.54x10⁻⁶M ; 3. [OH⁻] = 1.32x10⁻¹³M
Explanation:
Remember the rule:
pH + pOH = 14
pOH = 14 - pH
10*⁻pOH (you have to elevate 10, to -pOH)
10*⁻pOH = [OH⁻]
1. 14 - 13.48 = 0.52
10⁻⁰°⁵² = 0.30
2. 14 - 8.19 = 5.81
10⁻⁵°⁸¹ = 1.54x10⁻⁶
3. 14 - 2.12 = 12.88
10⁻¹²°⁸⁸ = 1.32x10⁻¹³
Let us assume that the ring is a size 7 ring, which has a circumference of 54.3 millimeters. Converting this to centimeters, the circumference of the ring is:
54.3 mm = 5.43 cm
Now, we determine the number of gold atoms that will be present in this:
5.43 / 1 x 10⁻⁹
There will be 5.43 x 10⁹ atoms
We now determine the number of moles this is by:
one mole = 6.02 x 10²³ atoms
Moles = 5.43 x 10⁹ / 6.02 x 10²³
Moles = 9.01 x 10⁻¹⁵ moles
The molar mass of gold is 197 g/mol
The mass is 9.01 x 10⁻¹⁵ * 197
The mass of the strand is 1.76 x 10⁻¹² grams
First, we need to know what's the gravity value in the moon. it is 1.622 m/ s2
to find the force, let's recall this formula----> Force= mass x gravity
force= 83 kg x 1.622= 134.6
A is the closest choice.
