Answer:
The answer to your question is pH = 1.45
Explanation:
Data
pH = ?
Volume 1 = 200 ml
[HCl] 1 = 0.025 M
Volume 2 = 150 ml
[HCl] 2 = 0.050 M
Process
1.- Calculate the number of moles of each solution
Solution 1
Molarity = moles / volume
-Solve for moles
moles = 0.025 x 0.2
result
moles = 0.005
Solution 2
moles = 0.050 x 0.15
-result
moles = 0.0075
2.- Sum up the number of moles
Total moles = 0.005 + 0.0075
= 0.0125
3.- Sum up the volume
total volume = 200 + 150
350 ml or 0.35 l
4.- Calculate the final concentration
Molarity = 0.0125 / 0.35
= 0.0357
5.- Calculate the pH
pH = -log [H⁺]
-Substitution
pH = -log[0.0357]
-Result
pH = 1.45
are hydrogen atoms which have lost protons
Answer:
The density of the metal sample is 2.70 
Explanation:
Density is a magnitude that allows you to measure the amount of mass in a given volume of a substance. Then, the expression for the calculation of density is the ratio between the mass of a body and the volume it occupies:

Density, according to the International System of Units, is usually expressed in kilograms per cubic meter (kg / m3) or gram per cubic centimeter (g / cm3). Although it can also be expressed in any other unit of mass by volume.
So, for the calculation of density you know that:
- mass of the sample= 10 grams
- volume of the sample = volume on the cylinder after immersion - volume on the cylinder before immersion= 38.7 mL - 35.0 ml = 3.7 mL
Then:

d=2.70 
<u><em>The density of the metal sample is 2.70 </em></u>
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Answer: Option (a) is the correct answer.
Explanation:
According to thermodynamics, a closed system is defined as the system in which there will be no exchange of matter takes place but there will be exchange of energy between the system and surrounding.
On the other hand, an open system is defined as the system in which there will be exchange of both matter and energy takes place between system and surrounding.
Hence, we can conclude that out of the given options accurate descriptions of closed and open thermodynamic processes is that open processes are 'flow through' processes.