5. B air is a mixture of many elements, but is not a chemically fused.
6. B Beef stew, composition varies throughout.
7. A. They can be chemically separated into their component elements, but they are all homogenous, and as such, have constant composition, which differs from the components properties, as the components must undergo a chemical change to become compounds.
Mass = mr x moles
Mr of CuCl2 = ( 63.5) + ( 35.5 x 2) = 134.5
2.5 = 134.5 x moles
2.5 / 134.5 = moles
Moles = 0.019 (2DP)
0.25g of Al
Mr of Al = 27
0.25 = 27 x moles
0.25/ 27 = 0.0093 moles (2sf)
Hope this helps :)
Given :
The distance between a point charge and a neutral atom and is multiplied by a factor of 5.
To Find :
By what factor does the force on the neutral atom by the point charge change.
Solution :
We know, electrostatic force between two object is directly proportional to product of charge and inversely proportional to distance between them.
Now, charge in neutral atom is 0 C.
So, the electrostatic force between two of them is also 0 N.
Therefore, by changing distance between the charge the forces did no change ( it remains zero).
