Answer:
(a) Between methanol (CH₃OH) and glycerol (C₃H₅(OH)₃), the substance with the higher surface tension is glycerol (C₃H₅(OH)₃)
(b) Between tetrabromomethane (CBr₄) and chloroform (CHCl₃), the substance with the higher surface tension is chloroform (CHCl₃)
Explanation:
The surface tension of these substances at 20 °C given in mN/m, is as follows:
The surface tension of Methanol is 22.70
The surface tension of Tetrabromomethane is 26.95
The surface tension of Glycerol is 64.00
The surface tension of Chloroform is 27.50
(a) Between methanol (CH₃OH) and glycerol (C₃H₅(OH)₃), the substance with the higher surface tension is glycerol (C₃H₅(OH)₃)
(b) Between tetrabromomethane (CBr₄) and chloroform (CHCl₃), the substance with the higher surface tension is chloroform (CHCl₃)
Answer: 14.1g
Explanation:
Given that,
number of moles of SiO2 = 0.235 moles
Mass in grams = Z (let unknown value be Z)
Molar mass of SiO2 = ?
To get the molar mass of SiO2, use the atomic mass
Silicon = 28g;
Oxygen = 16g
i.e Molar mass of SiO2 = 28g + (16g x 2)
= 28g + 32g
= 60g/mol
Now, apply the formula
Number of moles = Mass / molar mass
0.235 moles = Z / 60g/mol
Z = 0.235 moles x 60g/mol
Z = 14.1 g
Thus, the mass of SiO2 is 14.1 grams.
Answer:
The concentration of this sodiumhydroxide solutions is 0.50 M
Explanation:
Step 1: Data given
Mass of sodium hydroxide (NaOh) = 8.0 grams
Molar mass of sodium hydroxide = 40.0 g/mol
Volume water = 400 mL = 0.400 L
Step 2: Calculate moles NaOH
Moles NaOH = mass NaOH / molar mass NaOH
Moles NaOH = 8.0 grams / 40.0 g/mol
Moles NaOh = 0.20 moles
Step 3: Calculate concentration of the solution
Concentration solution = moles NaOH / volume water
Concentration solution = 0.20 moles / 0.400 L
Concentration solution = 0.50 M
The concentration of this sodiumhydroxide solutions is 0.50 M
