The number of atoms N = 5.8 x 10²¹
<h3>Further explanation</h3>
A mole is a unit of many particles (atoms, molecules, ions) where 1 mole is the number of particles contained in a substance that is the same amount as many atoms in 12 gr C-12
1 mole = 6.02.10²³ particles
mass of N in 0.82 g of NaNO₃ (MW NaNO₃: 85 g/mol) :
moles of N :
The number of atoms N :
The answer would be millimeters
so answer choice d
Answer: Kb = 3.15 × 10 ⁻⁴
Explanation:
This is how you calculate Kb for this reaction.
1) Equilibrium equation:
CH₃NH₂ + H₂O ⇄ CH₃NH₃⁺ + OH⁻
2) Kb = [CH₃NH₃⁺] [OH⁻] / [CH₃NH₂] ↔ all the spieces in equilibrium
3) From the stoichiometry [CH₃NH₃⁺] = [OH⁻]
Then, Kb = [OH⁻] [OH⁻] / [CH₃NH₂] = [OH⁻]² / [CH₃NH₂]
4) You get [OH⁻] from the pH in this way:
pOH + pOH = 14 ⇒ pOH = 14 - pH = 14 - 11.40 = 2.60
pOH = - log [OH⁻] = 2.60 ⇒ [OH⁻] = 10^(-2.6) = 0.002512
5) [CH₃NH₂] in equilibrium is given: 0.0200M
6) Now compute:
Kb = (0.002512)² / 0.0200 = 3.15 × 10 ⁻⁴
1. element
2. compound
3. element
4. compound
5. compound
6. compound
basically, if its on the periodic table, its an element. for example, rock can be made of many things in the periodic table, therefore its a compound. salt, is NaCl, which are two elements put together, therefore its a compound.
Molarity is equal to the number of moles of solute per liter solution.
number of moles solute: (molar mass of perchloric acid is 100.45 g/mol)
35.0 mL * (<span>1.67 g/mL) *0.705 * (mol/100.45 g) = 0.41 moles
liter solution = 2000 ml * (1 L/1000 ml) = 2 L
molarity is equal to 0.41 moles/ 2 L =0.205 M</span>
