Answer:
0.04 M
Explanation:
Given data:
Mass of Na₂SO₄= 14.2 g
Volume of solution = 2.50 L
Molarity of solution = ?
Solution:
Number of moles of Na₂SO₄:
Number of moles = mass/ molar mass
Number of moles = 14.2 g/ 142.04 g/mol
Number of moles = 0.1 mol
Molarity :
Molarity = number of moles of solute / volume of solution in L
Molarity = 0.1 mol / 2.50 L
Molarity = 0.04 M
The answer is d, hand soap.
Hand soap is alkaline and red litmus paper turns blue when exposed to alkaline solution.
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
C ........................
Answer:
3
Explanation:
Lt= Loe^(-kt)
Data:
Lo = 10 mg/mL
Assume k = 0.23/da
1. Calculate L5
L5 = 10e^(-5×0.23) = 10e^-1.15 = 10 × 0.317 = 3.17 mg/mL
2. Calculate the dilution factor
You expect to find L5 to be about 3
You want L5 to be about 1.
You should use a dilute your sample by a factor of 3.
P = 3
