Answer:
0.1 mol
Explanation:
Number of mole= mass/molar mass
lithium have a mass number of 7 and oxygen have a mass number of 16.
so, (7x2) + 16
= 30
therefore, number of moles = 2.93/30
= 0.10
Answer:
Acceleration = 3.5 m.s⁻²
Explanation:
Definition:
The acceleration is rate of change of velocity of an object with respect to time.
Formula:
a = Δv/Δt
a = acceleration
Δv = change in velocity
Δt = change in time
Units:
The unit of acceleration is m.s⁻².
Acceleration can also be determine through following formula,
F = m × a
a = F/m
Given data:
Force = 35 N (N = Kg. m.s⁻²)
Mass = 10.0 Kg
a = ?
Formula:
a = F/m
a = 35 Kg. m.s⁻²/ 10.0 Kg
a = 3.5 m.s⁻²
Answer: Option (C) is the correct answer.
Explanation:
When chemical composition of a substance is not changing in a chemical reaction then it is known as a physical change.
For example, when water change state, from ice to steam then it means solid state is changing into gaseous state.
Therefore, it is a physical change.
And, a reaction which causes change in chemical composition is known as a chemical change.
For example, 
Thus, we can conclude that we can see water change state, from ice to steam. This is a physical change in matter.
Answer:
put a test tube over the opening, remove it and quickly put a lit splint near the mout or in the tube. if you hear a squeaky pop it is hydrogen.
Explanation:
hydrogen ignites in air.
Answer : The molecular weight of a gas is, 128.9 g/mole
Explanation : Given,
Density of a gas = 5.75 g/L
First we have to calculate the moles of gas.
At STP,
As, 22.4 liter volume of gas present in 1 mole of gas
So, 1 liter volume of gas present in
mole of gas
Now we have to calculate the molecular weight of a gas.
Formula used :

Now put all the given values in this formula, we get the molecular weight of a gas.


Therefore, the molecular weight of a gas is, 128.9 g/mole