Answer: There are 
atoms of hydrogen are present in 40g of urea, 
.
Explanation:
Given: Mass of urea = 40 g
Number of moles is the mass of substance divided by its molar mass.
First, moles of urea (molar mass = 60 g/mol) are calculated as follows.
According to the mole concept, 1 mole of every substance contains 
atoms.
So, the number of atoms present in 0.67 moles are as follows.
In a molecule of urea there are 4 hydrogen atoms. Hence, number of hydrogen atoms present in 40 g of urea is as follows.
Thus, we can conclude that there are atoms of hydrogen are present in 40g of urea, .
Explanation:
It is known that charge on xenon nucleus is 
equal to +54e. And, charge on the proton is 
equal to +e. So, radius of the nucleus is as follows.
r = 
= 3.0 fm
Let us assume that nucleus is a point charge. Hence, the distance between proton and nucleus will be as follows.
d = r + 2.5
= (3.0 + 2.5) fm
= 5.5 fm
= 
(as 1 fm = 
)
Therefore, electrostatic repulsive force on proton is calculated as follows.
F = 
Putting the given values into the above formula as follows.
F =
= 
= 
= 411.2 N
or, = 
N
Thus, we ca conclude that N is the electric force on a proton 2.5 fm from the surface of the nucleus.
Answer:
100.8 dm3
Explanation:
mol= volume
_______
molar volume
Simply transpose the formula
volume=mol x molar volume
4.5molx22.4 mol/dm3
= 100.8dm3
NB STP=22.4 dm3 or 22400 cm3
Answer:
Option (A).
Explanation:
A). Structural formula
Structural formula of a chemical compound represents a graphic structure of a molecule.
B). Chemical formula
Chemical formula shows the chemical proportions of the atoms which constitute a molecule of the compound.
C). Space filling model
Space filling model is a 3-D molecular model in which atoms are represented by the spheres whose radii are proportional to the radii of the atoms and distances between the atoms are proportional to the distances between the atomic nuclei.
D). A ball and stick model
This model shows the 3-D positions of the atoms and the bonds between them.
In this model atoms are represented by the spheres and bonds connected by the sticks.
Therefore, model shown is STRUCTURAL FORMULA.
Option (A) is the answer.
Answer:
a and d
Explanation:
boiling is a chemical change ans rottong is a chemcal change, both requiring heat
