Prepare 0.1N working standard solution in 250ml distilled water from stock standard solution 20% Na2CO3 in 50ml of distilled water, If you know that the A. wt of Na=32,O=16,C=12? A) 5 ml
B) 8.5 ml
C) 5.8 ml
D) 3 ml

what is the way i should follow to get the answer ?!!

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?