Mg + 1/2 O2 → MgO
1 mol = 24 g of Mg
X mol = 12 g of Mg
x = 0.5 moles of Mg
Mg :MgO = 1:1 (coefficient from equations using mole ratio)
So
0.5 moles of MgO
1 mol MgO = (24+16) g = 40 g
0.5 moles of MgO = 0.5 × 40
= 20 g of MgO produced
The answer for the following question is option "C".
Option C is not included in the John Dalton's modern theory of an atom.
- "It states atoms of different elements combine to form new compound" but not new elements
Explanation:
According to John's Dalton's modern theory of an atom:
1. All matter is composed of atoms.
2. Atoms cannot be created,destroyed or subdivided in the ordinary chemical reactions.
3. Atoms of one element differ in the properties from atoms of an another element.
(i.e.)Each and every atom of the element has its own unique properties of their own.
4. Atoms of one element combine with the atoms of another element to <u>form new compound.</u>
5. Atoms that make up an element are identical to each other.
Answer and Explanation:
The resonance contributor in cyclopentadienone (as shown in the attachment below) results into the compound having a positive charge on the carbonyl group, C=O which accounts for a highly reactive anti-aromatic 4π system. And this illustrates the reason for its instability.
You can use the follwing equations.
pH=14-pOH
pOH=-log[OH⁻]
a) pOH=-log10⁻¹²
pOH=12
pH=14-12
pH=2
You can also use these equations:
[H⁺]=K(w)/[OH⁻] (K(w)=1.01×10⁻¹⁴)
pH=-log[H⁺]
b) [H⁺]=(1.01×10⁻¹⁴)/10⁻²M
[H⁺]=1.01×10⁻¹²M²
pH=-log(1.01×10⁻¹²)
pH=12
You can use either method. It does not really matter.
I hope this helps. Let me know if anything is unclear and when you do the calculations for c you should get pH=7.
