Answer:
334.2× 10²³ molecules
Explanation:
Given data:
Mass of water = 1 Kg ( 1000 g )
Number of molecules = ?
Solution:
Number of moles of water:
Number of moles = mass/ molar mass
Number of moles = 1000 g/ 18 g/mol
Number of moles = 55.5 mol
1 mole contain 6.022× 10²³ molecules
55.5 mol×6.022× 10²³ molecules
334.2× 10²³ molecules
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
A vibrating string can create longitudinal waves as depicted in the animation below.
The answer is C) vibrations
Nuclear fusion in the sun involves hydrogen (H) atoms
combining to form helium (He). A student claims that since the atmosphere
contains hydrogen, any fusion reaction on Earth would result in an uncontrolled
chain reaction. What is wrong in the student’s reasoning is that the uncontrolled
chain reactions can only happen during nuclear fission.
B: dna cells should be the answer