44. (a) N2O3 (b) SF4 (c) AlCl3 (d) Li2CO3
46. H Br
δ+ δ−
48. The metallic potassium atoms lose one electron and form +1 cations,
and the nonmetallic fluorine atoms gain one electron and form –1 anions.
K → K+
+ e–
19p/19e–
19p/18e–
F + e–
→ F–
9p/9e–
9p/10e–
The ionic bonds are the attractions between K+
cations and F–
anions.
50. See Figure 3.6.
52. (a) covalent…nonmetal-nonmetal (b) ionic…metal-nonmetal
54. (a) all nonmetallic atoms - molecular (b) metal-nonmetal - ionic
56. (a) 7 (b) 4
58. Each of the following answers is based on the assumption that nonmetallic
atoms tend to form covalent bonds in order to get an octet (8) of
electrons around each atom, like the very stable noble gases (other than
helium). Covalent bonds (represented by lines in Lewis structures) and lone
pairs each contribute two electrons to the octet.
(a) oxygen, O
If oxygen atoms form two covalent bonds, they will have an octet of electrons
around them. Water is an example:
H O H
(b) fluorine, F
If fluorine atoms form one covalent bond, they will have an octet of electrons
around them. Hydrogen fluoride, HF, is an example:
H F
(c) carbon, C
If carbon atoms form four covalent bonds, they will have an octet of electrons
around them. Methane, CH4, is an example:
H H
H
H
C
(d) phosphorus, P
If phosphorus atoms form three covalent bonds, they will have an octet
Answer: The empirical formula of the compound becomes 
<u>Explanation:</u>
The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.
We are given:
Mass of C = 48.38 g
Mass of H = 6.74 g
Mass of O = 53.5 g
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
......(1)
To formulate the empirical formula, we need to follow some steps:
- <u>Step 1:</u> Converting the given masses into moles.
Molar mass of C = 12 g/mol
Molar mass of H = 1 g/mol
Molar mass of O = 16 g/mol
Putting values in equation 1, we get:
- <u>Step 2:</u> Calculating the mole ratio of the given elements.
Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 3.023 moles
- <u>Step 3:</u> Taking the mole ratio as their subscripts.
The ratio of C : H : O = 1 : 2 : 1
Hence, the empirical formula of the compound becomes
The process, in broad terms, would be the carbon cycle.
Answer:
The second choice: physical change because even though gas formation was observed, the water was undergoing a state change, which means that its original properties are preserved
(WAS ALREADY ANSWERED PREVIOUSLY)
