Answer: 
Explanation:
Significant figures : The figures in a number which express the value or the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
Rules for significant figures:
Digits from 1 to 9 are always significant and have infinite number of significant figures.
All non-zero numbers are always significant.
All zero’s between integers are always significant.
All zero’s after the decimal point are always significant.
All zero’s preceding the first integers are never significant.
Thus
has three significant figures
Answer:
The K sp Value is 
Explanation:
From the question we are told that
The of
is = 122.5 g/ mol
The mass of
dissolved is 
The volume of solution is 
The number of moles of
is mathematically evaluated as

Substituting values


Generally concentration is mathematically represented as
For


The dissociation reaction of
is

The solubility product constant is mathematically represented as

Since there is no ionic reactant we have
![K_{sp} = [k^+] [ClO_3^-]](https://tex.z-dn.net/?f=K_%7Bsp%7D%20%3D%20%5Bk%5E%2B%5D%20%5BClO_3%5E-%5D)



<u>Answer:</u>
<em>The specific heat capacity for gold in 105 joules which are required to heat 30.0 grams of gold is 0.129 J/(g℃)</em>
<u>Explanation:</u>
We make use of the formula

where
∆T = final T - initial T
= 54.9℃ - 27.7℃ = 27.2℃
Q is the heat energy in Joules = 105J
c is the specific heat capacity = ?
m is the mass of Gold = 30.0g

Rearranging the formula


So,
c = 0.129 J/(g℃)
(Answer)
Answer:
Cu(OH)₂ will precipitate first, with [OH⁻] = 2.97x10⁻¹⁰ M
Explanation:
The equilibriums that take place are:
Cu⁺² + 2OH⁻ ↔ Cu(OH)₂(s) ksp = 2.2x10⁻²⁰ = [Cu⁺²]*[OH⁻]²
Co⁺² + 2OH⁻ ↔ Co(OH)₂(s) ksp = 1.3x10⁻¹⁵ = [Co⁺²]*[OH⁻]²
Keep in mind that <em>the concentration of each ion is halved </em>because of the dilution when mixing the solutions.
For Cu⁺²:
2.2x10⁻²⁰ = [Cu⁺²]*[OH⁻]²
2.2x10⁻²⁰ = 0.25 M*[OH⁻]²
[OH⁻] = 2.97x10⁻¹⁰ M
For Co⁺²:
1.3x10⁻¹⁵ = [Co⁺²]*[OH⁻]²
1.3x10⁻¹⁵ = 0.25 M*[OH⁻]²
[OH⁻] = 7.21x10⁻⁸ M
<u>Because Copper requires less concentration of OH⁻ than Cobalt</u>, Cu(OH)₂ will precipitate first, with [OH⁻] = 2.97x10⁻¹⁰ M