Answer:
The mass of 1.26 mole of water, H₂O, is 22.68 grams
Explanation:
Molar mass is the amount of mass that a substance contains in one mole. In other words, the molar mass of an atom or a molecule is the mass of one mole of that particle and its unit is g/mole.
In this case, being:
the molar mass of water H₂O is:
H₂O= 2*1 g/mole + 16 g/mole= 18 g/mole
Then you can apply the following rule of three: if 18 grams are present in 1 mole of H2O, how much mass is present in 1.26 moles of water?

mass= 22.68 grams
<u><em>The mass of 1.26 mole of water, H₂O, is 22.68 grams</em></u>
Answer:
the sun is the smallest object in our Solar System
Explanation:
Since this equation is balanced, we know that the law of conversation of mass id applied, and we could calculate easily.
Na= 2
NO3= 2
Ca= 1
<span>Cl= 1</span>
Answer:
The speed of an electron is 0.01908 m/s.
Explanation:
De-Broglie wavelength is given by:

where,
= wavelength of a particle
h = Planck's constant = 
m = mass of particle
v = velocity of the particle
Velocity of an electron = v
Mass of an electron = 
Wavelength of electron is twice the displacement in seconds which is velocity of an electron.
Then.wavelength of an electron = 

v = 0.01908 m/s
The speed of an electron is 0.01908 m/s.