As the question tells you, you need to use the formula
% mass= mass of solute/ mass of solution x 100
mass solute= 30.0 g
mass of solution= 30.0 + 270.0= 300.0 g
% mass= 30.0/ 300.0 x 100= 10%
answer is B
Covalent for the first one
Answer:
No
Explanation:
given that, enthalpy is a state function, that means it depends only on the initial and final states, there is no difference between the enthalpy of a phase transition versus the enthalpy of a heating or cooling process, when the cooling or heating process finish in a change of phase.
It does not matter which way we take to cool or heat the substances the Enthalpy of this process will be the same.
Answer:
The separation between layers of atoms in the crystal is 164.52 pm.
Explanation:
Formula used
(Bragg's law)
Where :
n = an order of reflection (integer)
= wavelength of the beam incident X-ray
d = spacing between the layer
θ = incident angle ( angle between ray and scatter plane)
We have :
λ = 157 pm
θ = 28.5°
n = 1
d = ?
(Bragg's law)
The separation between layers of atoms in the crystal is 164.52 pm.
Answer:
12*2*6.022*10^23. Atoms of hydrogen.
Explanation:
First of all if u know that 1 molecule of calcium hydroxide contain 2 hydrogen atom and 1 mole of calcium hydroxide contain 6.022*10^23 molecules of calcium hydroxide.
Hence 1 mole of calcium hydroxide contain 2*6.022*10^23 atom of hydrogen.
So 12 mole of calcium hydroxide contain =12*2*6.022*10^23. Atoms of hydrogen.
