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 ?!!

How many moles are in 250 grams of tungsten (w)? * 4.4x10^23 moles 4.2x10^23 moles 0.7 moles 1.4 moles

Why do scientists look for patterns in the world? a. patterns can explain observations. b. patterns never change, no matter what. c. patterns are easy for scientists to detect. d. patterns are all the same, through all time.

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?