4. A
because PbCl2 is an ionic compound and it's solid, so it's a substance.
It cannot be mixture, because it's a pure molecule.
5. D
despite that both substances are gases, colorless they are different molecules, so they should have different either chemical and physical properties
6. C
this substance made from W atoms and others are made from molecules
You can make 0.288 L of 4M solution using 100g of lithium bromide
Answer:
x
Explanation:
becaue neutron equal to mass num -atomic num
