Average velocity is the change in distance divided by the time it takes to travel that distance. so the first one.
The correct answer is the second option. <span>Baking soda fizzing in vinegar is an example of a chemical change. This example is a chemical reaction which undergoes a chemical change since new substances are being formed the fizzing of the system represent that gas is being produced by the reaction.</span>
Answer:
valance electrons
Explanation:
these are the electrons in the outermost shell
Answer:
There are approximately 1.54 moles in a 275 g sample of
.
Explanation:
To find out number of moles, fistly we have to calculate molecular mass of
.
There are 2 atoms of Potassium 1 atom of Chromium and 3 atoms of oxygen in the given compound.
For molecular mass we have to add the value of mass of 2 atoms of Potassium with mass of 1 atom of Chromium and with mass of 3 atoms of oxygen.
Atomic mass of Potassium = 39
Atomic mass of Chromium = 52
Atomic mass of Oxygen = 16
Now,
Molecular mass of
= 
The molecular mass of a compound is the mass of compound in one mole.
To find out the number of moles, we have to divide given mass of compound by its molecular mass.


Hence the number of moles in 275 gm of
is 1.54.