Answer:
About 1.254 moles
Explanation:
The first step is to find the molar mass of selenium. If you take a look at a periodic table, you will find that there is a little number underneath that says something around 78.96 g/mol. Dividing 99 grams by this number, you get about 1.254 moles of Se. Hope this helps!
<h2>Answer:</h2>
pOH = 4.6
<h2>Explanations:</h2>
The sum of pH and pOH of a solution is 14as shown:

Given the following parameter
pH = 9.4
Substitute the given parameters into the formula to have:

Hence the pOH of the solution of pH of 9.4 is 4.6
Answer:
D. 450 J/kgK
Explanation:
Using the formula as follows:
Q = m × c × ∆T
Where:
Q = amount of heat absorbed/released (J)
m = mass of substance (g)
c = specific heat capacity
∆T = change in temperature (°C)
According to the information provided in this question:
Q = 267.3 kJ = 267300J
m = 18kg
∆T = 318K - 285K = 33K
c = ?
Q = m × c × ∆T
c = Q ÷ m∆T
c = 267300 ÷ 18 × 33
c = 267300 ÷ 594
c = 450 J/kgK
Answer:
168.56 mL
Explanation:
density = mass/volume, use basic algebra skills to replace the volume and solve