Answer:
39.6 g
Explanation:
The equation of the reaction is;
2Mg(s) + O2(g) --------> 2MgO(s)
To obtain the limiting reactant;
Number of moles in 26.4 g of Mg = 26.4g/24 g/mol = 1.1 moles
If 2 moles of Mg yields 2 moles of MgO
1.1 moles of Mg yields 1.1 * 2/2 = 1.1 moles of MgO
Number of moles in 26.4 g of O2 = 26.4 g/32g/mol = 0.825 moles
If 1 mole of O2 yields 2 moles of MgO
0.825 moles of O2 yields 0.825 moles * 2/1 = 1.65 moles of MgO
Hence Mg is the limiting reactant.
Theoretical yield of MgO = 1.1 moles of MgO * 40 g/mol = 44 g
Percent yield = 90%
Percent yield = actual yield/theoretical yield * 100
Actual yield = Percent yield * theoretical yield/100
Actual yield = 90 * 44/100
Actual yield = 39.6 g
18 is the max number of electrons in 1 orbital
Question options:
A) K2SO4
B) FeCl₃
C) NaOH
D) NH₃
E) KCl
Answer:
D. NH₃
Explanation:
K2SO4 = 2 K+ + SO42-
[K+]= 2 x 1.0 = 2.0 M ; [SO42-] = 1.0 M
total concentrations of ions = 2.0 + 1.0 = <em>3.0 M</em>
FeCl3 = Fe3+ + 3Cl-
[Fe3+] = 1.0 M ; [Cl-] = 3 x 1.0 = 3.0
total concentration ions = 1.0 + 3.0 =<em> 4.0 M</em>
NaOH = Na+ + OH-
[Na+] = [OH-] = 1.0 M
total concentration ions = 1.0 + 1.0 = <em>2.0 M</em>
<u>NH3 is a weak acid so the concentration of NH4+ and OH- </u><u><em>< 2.0</em></u>
KCl = K+ + Cl-
[K+] = [Cl-] = 1.0 M
total concentration ions = 1.0 + 1.0 =<em> 2.0 M</em>
<h3><u>Answer;</u></h3>
C) A convex lens has a thick center and thin edges; a concave lens has a thin center and thicker edges.
<h3><u>Explanation;</u></h3>
- Convex lens refers to the lens which merges the light rays at a particular point, that travels through it, while a concave lens can be identified as the lens which disperses the light rays around, that hits the lenses.
- A convex lens is thicker at the center, as compared to its edges, while a concave lens is thinner at the center as compared to its edges.
- A concave lens is thicker at the edges than in the middle and spreads light rays apart producing an image smaller than the actual object. A convex lens on the other hand, is thinner at the edges and thicker towards the center, that is they are bent towards a central point.
