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Juliette [100K]
3 years ago
13

determine the total water hardness in a 25.00 mL sample of water that require 12.45 ml of 0.01111m edta for titration

Chemistry
1 answer:
Ksenya-84 [330]3 years ago
4 0
Water hardness is often expressed or defined as the content of the ions of Calcium and magnesium that make it "hard". To know the total hardness of water, EDTA titration is often used expressed as the mol of EDTA per liter of Solution.
mol of solute = (12.45 mL)(0.01111 mol/L)*(1L/1000mL)=1.3832 x 10-4.
Therefore, water hardness = 1.3832x10-4 mol/0.025 L = 5.53278x10^-3 M
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An evaporation–crystallization process of the type described in Example 4.5-2 is used to obtain solid potassium sulfate from an
timofeeve [1]

Answer:

feed = 220.77 kg/s; maximum production rate of solid crystal = 416 kg/s; the rate of supplying fresh feed to obtain the production rate = 1.6

Explanation:

Material or mass balance can be used to estimate the mass flow rates of all the streams in the diagram shown in the attached file.

Overall balance: M_{1} = 175 + 11M_{2}

Water: 0.804M_{1} = 175 + 0.6M_{2}

Using substitution method, we have:

M_{1} = 220.77 kg/s

M_{2}  = 4.16 kg/s

The maximum production rate of solid crystal is 10M_{2} = 10*4.16 = 416 kg/s

Around evaporator:

0.45M_{5} = 175

M_{5} = 175/0.45 = 389 kg/s

Around the mixing point:

M_{1} + M_{3} = M_{4} + M_{5}

Solid crystal: 0.196M_{1} + 0.4M_{3} = M_{4}

Using the last two equations, we can obtain:

0.804M_{1} + 0.6M_{3} = M_{5}

0.6M_{3} = 389 - 0.804*220.77 = 389 - 177.5 = 211.5

M_{3} = 211.5/0.6 = 352.5 kg/s

The rate of supplying fresh feed to obtain the production rate is:

\frac{M_{3}}{M_{1}} = 352.5/220.77 = 1.6

7 0
3 years ago
If an atom of sodium combines with (captures) an alpha particle that has 2 protons and 2 neutrons, its new mass number will be
GuDViN [60]

Answer:

27 amu

Explanation:

The alpha particles is Helium nuclei.

Atomic mass is the sum of the neutrons and protons.

Helium have two protons and two neutrons thus its atomic mass is 4 amu.

₂He⁴

Sodium atom have 12 neutrons and 11 protons. Thus its mass number will be

23 amu.

When it combine with alpha particle it mass will be 27 amu.

23 amu + 4 amu = 27 amu.

Thus new sodium atom have 14 neutrons and 13 protons.

6 0
3 years ago
Metallic behavior is generally associated with elements with partially filled p orbitals. elements with unpaired electrons. elem
Mila [183]

Answer:

Elements with low ionization energies.

Explanation:

The ionization energy of an atom reffers to the amount of energy that is required to remove an electron from the gaseous form of that atom or ion.

The greater the ionization energy, the more difficult it is to remove an electron. The ionization energybis one of the indicator that shows the reactivity of an element. Elements with a low ionization energy such as metals are usually reffered to as a reducing agents and form cations, this give metals the tendency to

give away their valence electrons when bonding, whereas non-metals tend to take electrons.

Metallic elements have different properties such as shiny, heat and electricity conductivity . They are malleable and ductile Some metals, such as sodium, are soft and can be cut with a knife. while some are very hard such as iron.

4 0
3 years ago
When might a plot of ln[a] vs time not yield a straight line?
podryga [215]
Considering a reaction:
A → B
The rate equation may be described as:
r = -k[A]ⁿ
Taking the natural log,
ln(r) = -nln([A]) + ln(k)
Therefore, the only time the graph of ln[A] vs time will be a straight line is when the order of the reaction is 0, meaning the reaction is independent of reactant concentration.
6 0
3 years ago
If we have equal masses of copper at 80oC and water at 20oC and we put them together, what is the final temperature?
Ket [755]

Answer:

The final temperature will be close to 20°C

Explanation:

First of all, the resulting temperature of the mix can't be higher than the hot substance's (80°C) or lower than the cold one's (20°C). So options d) and e) are imposible.

Now, due to the high heat capacity of water (4,1813 J/mol*K) it can absorb a huge amount of heat without having a great increment in its temperature. On the other hand, copper have a small heat capacity (0,385 J/mol*K)in comparison.

In conclusion, the copper will release its heat decreasing importantly its temperature and the water will absorb that heat resulting in a small increment of temperature. So the final temperature will be close to 20°C

<u>This analysis can be done because we have equal masses of both substances. </u>

6 0
3 years ago
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