“Zn” is a... <br><br><br> Chemicals Formula <br><br><br> Symbol <br><br><br> Name

A student titrates 25.00 ml. of tap water using 4.86 mL of 0.020 M EDTA. Calculate the hardness of the water

chubhunter [2.5K]

Answer:

0.0038 M

Explanation:

Hardness of the water is generally due to the presence of $CaCO_3$ in water.

At equivalence point

Moles of $Ca^{2+}$ = Moles of EDTA

Considering

$Molarity_{Ca^{2+}}\times Volume_{Ca^{2+}}=Molarity_{EDTA}\times Volume_{EDTA}$

Given that:

$Molarity_{EDTA}=0.020\ M$

$Volume_{EDTA}=4.86\ mL$

$Volume_{Water\ or\ Ca^{2+}}=25.00\ mL$

So,

$Molarity_{Ca^{2+}}\times 25=0.020\times 4.86$

$Molarity_{Ca^{2+}}=0.0038\ M$

6 0

3 years ago

Please help my class ends in a couple hours

marishachu [46]

Answer:

Homogeneous mixture

Solution

Liquid-gas

Hope this helps, hope its not late.

4 0

3 years ago

Read 2 more answers

What is the value of for this aqueous reaction at 298 K? <br><br>A+B↽⇀C+D ΔG°=12.86 kJ/mol<br><br>K=

agasfer [191]

Answer:

The equilbrium constant is 179.6

Explanation:

To solve this question we can use the equation:

ΔG = -RTlnK

<em>Where ΔG is Gibbs free energy = 12.86kJ/mol</em>

<em>R is gas constant = 8.314x10⁻³kJ/molK</em>

<em>T is absolute temperature = 298K</em>

<em>And K is equilibrium constant.</em>

Replacing:

12.86kJ/mol = -8.314x10⁻³kJ/molK*298K lnK

5.19 = lnK

e^5.19 = K

179.6 = K

<h3>The equilbrium constant is 179.6</h3>

8 0

3 years ago

NH3 is an example of A. an element. B. an atom. C. a mixture. D. a compound.

Keith_Richards [23]

Answer:

I believe it's an example of a compound.

4 0

4 years ago

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the temperature of a balloon rises from 275 degrees k to 395 degrees k, what would the ending volume be if it started at 5 L

Airida [17]

<h3>Answer:</h3>

7.182K

<h3>Explanation:</h3>

From the question we are given;

Initial temperature, T1 = 275 K
Final temperature, T2 = 395 K
Initial volume, V1 = 5 L

We are required to calculate the final volume, V2

Charles's law is the law that relates the volume of a gas and its temperature.
It states that the volume of a fixed mass of a gas and its absolute temperature are directly proportional at a constant pressure.
Therefore;

$\frac{V1}{T1}=\frac{V2}{T2}$

To calculate, V2 we rearrange the formula;

$V2=\frac{V1T2}{T1}$

$V2=\frac{(5L)(395K)}{275}$

$V2=7.182K$

Therefore, the ending volume will be 7.182K

8 0

4 years ago

“Zn” is a... Chemicals Formula Symbol Name