Answer:
In the third tube, the concentration is 0.16 ug/mL
Explanation:
In the first step, the solution is diluted by 5. Then, the concentration will be
20 ug/mL / 5 = 4 ug/mL
Then, in the second step this 4 ug / ml solution is diluted by a factor of five again:
4 ug /ml / 5 = 0.8 ug/mL
This solution is then diluted again by 5 and the concentration in the third tube will be then:
0.8 ug/mL / 5 = <u>0.16 ug/mL </u>
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Another way to calculate this is to divide the original concentration by the dilution factor ( 5 in this case) elevated to the number of dilutions. In this case:
Concentration in the third tube = 20 ug/mL / 5³ = 0.16 ug/mL
Answer:
pH = 1.683
Explanation:
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Answer:
Q = 9460 Kj
Explanation:
Given data:
Mass of copper = 2kg
Latent heat of vaporization = 4730 Kj/Kg
Energy required to vaporize 2kg copper = ?
Solution:
Equation
Q= mLvap
It is given that heat required to vaporize the one kilogram copper is 4730 Kj thus, for 2 kg
by putting values,
Q= 2kg × 4730 Kj/Kg
Q = 9460 Kj
Answer:
11.9 is the pOH of a 0.150 M solution of potassium nitrite.
Explanation:
Solution : Given,
Concentration (c) = 0.150 M
Acid dissociation constant = 
The equilibrium reaction for dissociation of 
(weak acid) is,
initially conc. c 0 0
At eqm. 
First we have to calculate the concentration of value of dissociation constant 
.
Formula used :
Now put all the given values in this formula ,we get the value of dissociation constant .
By solving the terms, we get
No we have to calculate the concentration of hydronium ion or hydrogen ion.
![[H^+]=c\alpha=0.150\times 0.0533=0.007995 M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3Dc%5Calpha%3D0.150%5Ctimes%200.0533%3D0.007995%20M)
Now we have to calculate the pH.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
pH + pOH = 14
pOH =14 -2.1 = 11.9
Therefore, the pOH of the solution is 11.9
Here are three everyday situations which it would be useful to identify unknown substances:
1. When you have two clear substances with no labels yet you are not sure which substance is water and which one is not and not knowing what this unknown chemical might do.
2. A stain on your clothes
3. When you are not feeling well and your sense of taste is not functioning well.
The ways that these can be identified is first, start by the appearance, for example the state, color, texture, etc. And secondly, use your sense of smell. This sense is also helpful in identifying whether the substance is something strong or not.
