Answer:
D
Explanation:
Because the atomic number is 8, we can see that it is indeed an isotope of oxygen. If the mass number is 18, this means that the protons and neutrons added together = 18, so there are 10 neutrons. It does not have an atomic mass of 15.9994 like the element on the periodic table, however, as this is a confirmed isotope and not an average.
Answer:
0.1795 M
Explanation:
From the given information:
The equation is:

From the above equation, the reaction will go to completion due to the strong base:
At the equivalence point, moles of acid (HF) will be equal to moles of base (KOH)

Thus. since moles of HF = moles of KOH
Then; 0.020 × 0.393 M = 0.02379 × (x) M
(x) M = 
(x) = 0.3304 M
Thus, the molarity of KOH = 0.3304 M
Using the balanced neutralization reaction;
moles of HF = moles of KOH = moles of conjugate base = 0.00786 mol
∴
Volume = 0.020 L + 0.02379 L
Volume = 0.04379 L
Volume of the solution = 0.04379 L
Therefore; Molarity = 
Molarity = 
Molarity = 0.17949 mol/L
= 0.1795 M
C
Animal cells do not have cell walls or chloroplasts!
Density is defined as mass per unit volume.

the mass of 1 mL of CO₂ is - 0.0019 g
3.5 L = 3500 mL
then the mass of 3500 mL of CO₂ is - 0.0019 g/mL x 3500 mL = 6.65 g
mass of 3.5 L of CO₂ is 6.65 g