Answer:
0.250L of solution. 0.250 moles of solute.
Explanation:
As you can see in the image, there is a beaker with an amount of solution. 1/2L are 500mL and each line of the beaker represents 100mL. That means the volume of the solution is approximately 250mL = 0.250L
Molarity is an unit of concentration defined as the moles of solute per liter of solution. A solution that is 1.000M contains 1.000 moles of solute per liter of solution.
As the volume of the solution is 0.250L, the moles are:
0.250L * (1.000mol/L) = 0.250 moles of solute
Explanation:
Atomic number means the number of protons an atom holds. Whereas mass number equals (number of protons + number of neutrons).
The given figure shows that there are 9 neutrons and 8 protons.
Therefore,
mass number of the atom = number of protons + number of neutrons
= 8 + 9
= 17
Hence, mass number of the atom is 17 and atomic number of the atom is 8.
Answer:
energy is released in the reaction.
Explanation:
Answer:
Cement is a compound mixdure, so cannot be an element.
Explanation:
<span>Answer: 100 ml
</span>
<span>Explanation:
1) Convert 1.38 g of Fe₂S₃ into number of moles, n
</span>i) Formula: n = mass in grass / molar mass
<span>
ii) molar mass of </span><span>Fe₂S₃ =2 x 55.8 g/mol + 3 x 32.1 g/mol = 207.9 g/mol
</span>
iii) n = 1.38 g / 207.9 g/mol = 0.00664 moles of <span>Fe₂S₃
</span>
<span>2) Use the percent yield to calculate the theoretical amount:
</span>
<span>65% = 0.65 = actual yield/ theoretical yield =>
</span>theoretical yield = actual yield / 0.65 = 0.00664 moles / 0.65 = 0.010 mol <span>Fe₂S₃</span><span>
3) Chemical equation:
</span>
<span> 3 Na₂S(aq) + 2 FeCl₃(aq) → Fe₂S₃(s) + 6 NaCl(aq)
4) Stoichiometrical mole ratios:
</span>
<span>3 mol Na₂S : 2 mol FeCl₃ : 1 mol Fe₂S₃ : 6 mol NaCl
5) Proportionality:
</span>2moles FeCl₃ / 1 mol Fe₂S₃ = x / 0.010 mol Fe₂S₃
<span>
=> x = 0.020 mol FeCl₃
6) convert 0.020 mol to volume
</span>
<span>i) Molarity formula: M = n / V
</span>
<span>ii) V = n / M = 0.020 mol / 0.2 M = 0.1 liter = 100 ml
</span>
