A = mass number, A = protons + neutrons
Z = atomic number, Z = protons
neutrons = A - Z
neutrons = 18 - 8 = 10
Answer:
<h3>The answer is 78 g</h3>
Explanation:
The mass of a substance when given the density and volume can be found by using the formula
<h3>mass = Density × volume</h3>
From the question
volume = 10 cc
density = 7.8 g/cc
So we have
mass = 7.8 × 10
We have the final answer as
<h3>78 g</h3>
Hope this helps you
Answer:
2.25 M is the final concentration of hydroxide ions ions in the solution after the reaction has gone to completion.
Explanation:
Moles of NaOH = 
Molarity of the nitric acid solution = 0.250 M
Volume of the nitric solution = 0.150 L
Moles of nitric acid = n



According to reaction, 1 mole of nitric acid recats with 1 mole of NaOH, then 0.0375 moles of nitric acid will react with :
of NaOH
Moles of NaOH left unreacted in the solution =
= 0.375 mol - 0.0375 mol = 0.3375 mol

1 mole of sodium hydroxide gives 1 mol of sodium ions and 1 mole of hydroxide ions.
Then 0.3375 moles of NaOH will give :
of hydroxide ion
The molarity of hydroxide ion in solution ;

2.25 M is the final concentration of hydroxide ions ions in the solution after the reaction has gone to completion.
The average density of the peat moss in units of g/cm³ is 2.52 g/cm³
<h3>How to convert 40 lb to grams (g)</h3>
We'lol begin by converting 40 lb to grams (g). This can be obtained as follow:
1 lb = 453.592 g
Therefore,
40 lb = (40 × 453.592) / 1 lb
40 lb = 18143.68 g
<h3>How to convert 1.9 gal to cm³</h3>
We can convert 1.9 gal to cm³ as follow:
1 gal = 3785.41 cm³
Therefore,
1.9 gal = (1.9 gal × 3785.41 cm³) / 1 gal
1.9 gal = 7192.279 cm³
<h3>How to determine the density </h3>
The density can be obtained as follow:
- Mass = 18143.68 g
- Volume = 7192.279 cm³
- Density =?
Density = mass / volume
Density = 18143.68 / 7192.279
Density = 2.52 g/cm³
Learn more about density:
brainly.com/question/952755
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4.) D
10.) C
12.) D
13.) D
14.) D
15.) D