The answer is: Dividing the number of molecules in the sample by Avogadro's number.
The Avogadro’s number is the number of atoms in 12 grams of the isotope carbon-12 (¹²C).
Na is Avogadro number or Avogadro constant (the number of particles, in this example carbon, that are contained in the amount of substance given by one mole).
The Avogadro number has value 6.022·10²³ 1/mol in the International System of Units; Na = 6.022·10²³ 1/mol.
For example:
N(Ba) = 2.62·10²³; number of atoms of barium.
n(Ba) = N(Ba) ÷ Na.
n(Ba) = 1.3·10²⁴ ÷ 6.022·10²³ 1/mol.
n(Ba) = 2.158 mol; amount of substance of barium.
Answer:
Plastic is an insulator
Explanation:
This enables you to touch it without burning yourself because it does not conduct heat easily.
Answer:
- Acid-Base reaction (the reactanct acting as a base is NaOH)
Explanation:
The reaction that takes place is:
- C₃H₅O(CO₂H)₃(aq) + 3OH⁻ (aq) → C₃H₅O(CO₂)₃⁻³(aq) + 3H₂O(l)
This is a <em>acid-base reaction</em>, with the citric acid acting as the acid and the <u>sodium hydroxide NaOH acting as the base.</u>
We <u>calculate the moles of citric acid</u> using the information from the titration:
- 0.0142 L * 0.340 M *
= 1.609x10⁻³ mol citric acid
Now we <u>convert moles to mass</u> using the acid's molecular weight (192.13g/mol):
- 1.609x10⁻³ mol citric acid * 192.13g/mol = 0.3092 g citric acid
Finally we calculate the mass percent of citric acid in the sample:
- 0.3092 g / 16.00 g * 100% = 1.93%
Answer:
Reaction with water: Aluminum oxide is insoluble in water and does not react like sodium oxide and magnesium oxide.
Answer is: <span>the molality of the glycerol solution is 10.03 m.
V(solution) = 100 mL.
m</span>(solution) = V(solution) · d(solution).
m(solution) = 100 mL ·1.120 g/mL.
m(solution) = 112 g.
m(glycerol) = ω(glycerol) · m(solution).
m(glycerol) = 0.48 · 112 g.
m(glycerol) = 53.76 g.
m(water) = 112 g - 53.76 g.
m(water) = 58.24 g ÷ 1000 g/kg = 0.05824 kg.
n(C₃H₈O₃) = m(C₃H₈O₃) ÷ M(C₃H₈O₃).
n(C₃H₈O₃) = 53.76 g ÷ 92 g/mol.
n(C₃H₈O₃) = 0.584 mol.
b(C₃H₈O₃) = n(C₃H₈O₃) ÷ m(H₂O).
b(C₃H₈O₃) = 0.584 mol ÷ 0.05824 kg.
m(C₃H₈O₃) = 10.027 mol/kg.
