Mass number is equal to the number of protons plus the number of neutrons in a nucleus of an atom
(also called Observational Error) is the difference between a measured quantity and its true value. It includes random error
Answer:
True
Explanation:
Thrust is the force which moves an aircraft through the air. Thrust is used to overcome the drag of an airplane, and to overcome the weight of a rocket. Thrust is generated by the engines of the aircraft through some kind of propulsion system.
Q1)
As Kemmi pipettes a volume of 25.00 ml of the solution
density of pure propanol is 0.803 g/ml
This means that in 1000 ml of solution - 0.803 g of pure propanol
Therefore in 25.00 ml of solution - 0.803 g x 25.00 ml / 1000 ml
= 0.0201 g
Using molar mass, number of moles can be calculated= 0.0201 g / 60.09 g/mol
= 3.35 x 10⁻⁴ mol
therefore the number of pure propanol moles in exactly 25.00 ml is
3.35 x 10⁻⁴ mol
Q2)
molarity is the concentration of the solution. It can be defined as the number of moles of solute per liter of solution
we know the number of moles in 25.00 ml of solution. When its diluted in a 100.00 ml volumetric flask, number of moles remain constant but now the volume over which the moles of solute are dissolved is increased.
therefore number of moles = 3.35 x 10^(-4) mol
volume over which its dissolved - 100.00 / 10³ dm³
= 1.0000 x10⁻¹ dm³
the molarity = 3.35 x 10⁻⁴ mol / 1.0000 x10⁻¹ dm³
= 3.35 x 10⁻³ mol/dm³
Answer:
condensation - B, melting - C, sublimation - A, freezing - D
Explanation:
condensation : condenstaion is process of change of phase of a substance from gaseous to liquid
evaporation : evaporation is process of change of phase of a substance from liquid to gaseous.
melting : melting is process of change of phase of a substance from solid to liquid.
freezing : freezing is process of change of phase of a substance from liquid to solid.
sublimation : sublimation is process of change of phase of a substance from solid to gaseous.
