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3 years ago

Which of the following substances can be decomposed by chemical change?

Chemistry

1 answer:

vovangra [49]3 years ago

8 0

NaCl can be decomposed by electrolysis

Na, Cl2 and K are in the simplest form and they cannot be decomposed

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A 50.0 mL solution of 0.141 M KOH is titrated with 0.282 M HCl . Calculate the pH of the solution after the addition of each of

Kobotan [32]

Answer:

pH =1 2.84

Explanation:

First we have to start with the reaction between HCl and KOH:

$HCl~+~KOH->~H_2O~+~KCl$

Now for example, we can use a volume of 10 mL of HCl. So, we can calculate the moles using the molarity equation:

$M=\frac{mol}{L}$

We know that $10mL=0.01L$ and we have the concentration of the HCl $0.282M$ , when we plug the values into the equation we got:

$0.282M=\frac{mol}{0.01L}$

$mol=0.282*0.01$

$mol=0.00282$

We can do the same for the KOH values ( $50mL=0.05L$ and $0.141M$ ).

$0.141M=\frac{mol}{0.05L}$

$mol=0.141*0.05$

$mol=0.00705$

So, we have so far 0.00282 mol of HCl and 0.00705 mol of KOH. If we check the reaction we have a molar ratio 1:1, therefore if we have 0.00282 mol of HCl we will need 0.00282 mol of KOH, so we will have an excess of KOH. This excess can be calculated if we substract the amount of moles:

$0.00705-0.00282=0.00423mol~of~KOH$

Now, if we want to calculate the pH value we will need a concentration, in this case KOH is in excess, so we have to calculate the concentration of KOH. For this, we already have the moles of KOH that remains left, now we need the total volume:

$Total~volume=50mL+10mL=60mL$

$60mL=0.06L$

Now we can calculate the concentration:

$M=\frac{0.00423mol}{0.06L}$

$M=0.0705$

Now, we can calculate the pOH (to calculate the pH), so:

$pOH=-Log(0.0705)$

$pOH=1.15$

Now we can calculate the pH value:

$14=~pH~+~pOH$

$pH=14-1.15=12.84$

8 0

3 years ago

What could two atoms of the same element form?

scZoUnD [109]

Covalent bonds but not ionic

8 0

3 years ago

Read 2 more answers

What is the name of the ionic compound RbCI

lorasvet [3.4K]

It would be Rubidium chloride.

6 0

3 years ago

HURRY !!!!!! How did kelper describe the planets Orbits ?

Andrei [34K]

Kepler's Laws of Planetary Motion. While Copernicus rightly observed that the planets revolve around the Sun, it was Kepler who correctly defined their orbits.

Sorry about the holds, copied it from google...

8 0

3 years ago

Help ….

VikaD [51]

Answer: 3 and 4 are the answers.

Explanation: i took the quiz.

7 0

3 years ago