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3 years ago

Please help..

Chemistry

1 answer:

Tamiku [17]3 years ago

4 0

Answer:

For a 1:100 dilution, one part of the solution is mixed with 99 parts new solvent. Mixing 100 µL of a stock solution with 900 µL of water makes a 1:10 dilution. The final volume of the diluted sample is 1000 µL (1 mL), and the concentration is 1/10 that of the original solution

Explanation:

i hope that gives you an idea

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16. You are running a TLC plate with a polar (A) and nonpolar substance (B); your solvent is a hexane and dichloromethane mixtur

IRISSAK [1]

Answer:

Acetone

Explanation:

Chromatography has to do with the separation of substances by eluting the components of the solute using a mobile phase. The composition of the mixture to be separated decides the mixture of solvents (mobile phase) that are to be used for elution.

In this case the mixture to be separated comprises of substance A which is polar and substance B which is non polar. It is observed that the mobile phase moves B up the plate but not the polar substance, A. This means that a polar solvent such as acetone should be added to the mobile phase in order to achieve better elution of A.

5 0

3 years ago

Which of the following has the highest boiling point?

My name is Ann [436]

Answer:

C.H2O has the highest boiling point.

I am not totally sure.

Hope it help you.

6 0

3 years ago

Li + HNO3 > LiNO3 + H2 how do I balance it? Show work pls

azamat

Answer: The balanced equation is $2Li + 2HNO_{3} \rightarrow 2LiNO_{3} + H_{2}$ .

Explanation:

The given reaction equation is as follows.

$Li + HNO_{3} \rightarrow LiNO_{3} + H_{2}$

Number of atoms present on reactant side are as follows.

Li = 1
H = 1
$NO_{3}$ = 1

Number of atoms present on product side are as follows.

Li = 1
H = 2
$NO_{3}$ = 1

To balance this equation, multiply Li by 2 and $HNO_{3}$ by 2 on reactant side. Also, multiply $LiNO_{3}$ by 2 on product side.

Hence, the equation can be rewritten as follows.

$2Li + 2HNO_{3} \rightarrow 2LiNO_{3} + H_{2}$

Now, number of atoms present on reactant side are as follows.

Li = 2
H = 2
$NO_{3}$ = 2

Number of atoms present on product side are as follows.

Li = 2
H = 2
$NO_{3}$ = 2

As there are same number of atoms on both reactant and product side. Hence, the equation is now balanced.

Thus, we can conclude that the balanced equation is $2Li + 2HNO_{3} \rightarrow 2LiNO_{3} + H_{2}$ .

3 0

3 years ago

The specific heat of copper metal is 0.385 J/(g × °C). How much energy must be added to a 35.0 gram sample of copper to change t

Montano1993 [528]

Q = mC∆T

where: 
q = heat 
m = mass of substance = 35.0 grams 
C = 0.385 J/g*C 
∆T = change in temperature = 65C - 20C = 45C 

q = (35.0 g)*(0.385 J/g*C)*(45C) = 606 J

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3 years ago

Oxidation number for H+

liubo4ka [24]

Answer:

The oxidation state of H+ = +1. The Oxidation state of Zn2+ = +2. The oxidation state of H2 = 0. The sum is equal to zero because there are 2 H+ ions.

Explanation:

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3 years ago