Answer:
40.94 g
Explanation:
Given data:
Mass of NO₂ = ?
Volume = 20.0 L
Pressure = 110.0 Pka
Temperature = 25°C
Solution:
Pressure = 110.0 KPa (110/101 = 1.1 atm)
Temperature = 25°C (25+273 = 298.15 K)
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
n = PV/RT
n = 1.1 atm × 20.0 L / 0.0821 atm.L/ mol.K ×298.15 K
n = 22 / 24.5 /mol
n= 0.89 mol
Mass of NO₂:
Mass = number of moles × molar mass
Mass = 0.89 mol × 46 g/mol
Mass = 40.94 g
This is false. The amount of electrons in lithium (Li) is not 7, it is 3. There are 3 electrons in lithium.
Explanation:
When conducting a melting point experiment, if we were to heat a sample quickly. Large amount heat is provided instantly which would melt the crystals in the tube very quickly, even before the temperature of the thermometer reaches to that level. So the observes melting point would be much lower than the actual melting point when sample is heated slowly.
Answer: Option (3) is the correct answer.
Explanation:
A reaction due to which there occurs change in chemical composition of reactants is known as a chemical reaction.
For example, evolution of heat when two substances combine together shows a chemical reaction has taken place between the substances.
Whereas a reaction which does not bring any changes in chemical composition of the reactants is known as a physical reaction.
For example, boiling point, melting point, mass, volume etc are all physical properties.
Thus, we can conclude that out of the given options a substance melts when sitting in the Sun, is not an indication of a chemical reaction.
