Answer:
The molarity of the solution is 7.4 mol/L
Explanation:
From the question above
0.400 ml of water contains 1.00 g of hydrochloride form of cocaine
Therefore 1000 ml of water will contain x g of hydrochloride form of cocaine
x = 1000 / 0.400
x = 2500 g
2500g of hydrochloride form of cocaine is present in 1000 ml of water.
Mole of hydrochloride form of cocaine = mass /molar mass of hydrochloride
Mole of hydrochloride form of cocaine = 2500/339.8
= 7.4 mol
Molarity = mol/ volume in liter (L)
molarity = 7.4 /1
Molarity = 7.4 mol/L
The choices for this are as follows:
A) gases; solids
B) metals; nonmetals
C) nonmetals; metals
<span>D) reactive; nonreactive
</span>
I think the correct answer is option B. The stair-step line between the pink squares and the yellow squares separates the metals from the nonmetals. Hope this helps.
Answer:
He is wrong . Most accurate is Buret .
Explanation:
The number of significant figure denotes the level of accuracy of a measurement .
Beaker can measure liquid in mL upto significant figure of 2 . That means it can measure volume in terms of 10 , 20 , 30mL etc . It can not measure 25 mL
accurately . The last figure of 28 mL is read by guess in the question . So it is not an accurate measurement .
Similarly , graduated cylinder can measure liquid upto significant figure of 3 . That means it can measure volume in terms of 11 , 22 , 33 mL etc . It can not measure 25.5 mL accurately . The last figure of 28.3 mL is read by guess in the question . So it is less accurate measurement .
Similarly , buret can measure liquid upto significant figure of 4 . That means it can measure volume in terms of 11.2 , 22.3 , 33.5 mL etc . It can not measure 25.53 mL accurately . The last figure of 28.32 mL is read by guess in the question . So it is most accurate among all the three instrument because it can measure accurately mL upto one tenth of it .
