Answer : The molecular weight of a substance is 157.3 g/mol
Explanation :
As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.
Mass of solute = 7 g
Mass of solution = 100 g
Mass of solvent = 100 - 7 = 93 g
Formula used :

where,
= change in freezing point
= temperature of pure water = 
= temperature of solution = 
= freezing point constant of water = 
m = molality
Now put all the given values in this formula, we get


Therefore, the molecular weight of a substance is 157.3 g/mol
Vertical columns are called groups, or families.
They share similar chemical properties.
Answer: <span>have similar chemical properties</span>
Conduction - by touch
Convection - hot air rises, cold air sinks
Insulation - to insulate or capture heat
Radiation - by waves
Direct contact means touch, therefore the answer would be conduction.
Answer:
0.234 moles
Explanation:
moles of Al2O3 = mass / molar mass
moles of Al2O3 = 23.87g / 102.0g/mol
moles of Al2O3 = 0.234 moles (to three significant figures)