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1 year ago

Which of these phrases would go in the overlap? Select two options.

Chemistry

2 answers:

AleksandrR [38]1 year ago

8 0

Yes they are correct

SVETLANKA909090 [29]1 year ago

5 0

I think it’s found in the nucleus and has a mass of one amu

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How can you identify gas in a chemical reaction without observing the atoms or molecules?

nikitadnepr [17]

Answer:

There are five signs of a chemical change:

Colour Change.

Production of an odour.

Change of Temperature.

Evolution of a gas (formation of bubbles)

Precipitate (formation of a solid).

5 0

2 years ago

Calculate the pH of the following simple solutions:

IceJOKER [234]

Answer :

(1) pH = 1.27

(2) pH = 13.35

(3) The given solution is not a buffer.

Explanation :

(1) 53.1 mM HCl

Concentration of HCl = $53.1mM=53.1\times 10^{-3}M$

As HCl is a strong acid. So, it dissociates completely to give hydrogen ion and chloride ion.

So, Concentration of hydrogen ion= $53.1\times 10^{-3}M$

pH : It is defined as the negative logarithm of hydrogen ion concentration.

$pH=-\log [H^+]$

$pH=-\log (53.1\times 10^{-3})$

$pH=1.27$

(2) 0.223 M KOH

Concentration of KOH = 0.223 M

As KOH is a strong base. So, it dissociates completely to give hydroxide ion and potassium ion.

So, Concentration of hydroxide ion= 0.223 M

Now we have to calculate the pOH.

$pOH=-\log [OH^-]$

$pOH=-\log (0.223)$

$pOH=0.65$

Now we have to calculate the pH.

$pH+pOH=14\\\\pH=14-pOH\\\\pH=14-0.65=13.35$

(3) 53.1 mM HCl + 0.223 M KOH

Buffer : It is defined as a solution that maintain the pH of the solution by adding the small amount of acid or a base.

It is not a buffer because HCl is a strong acid and KOH is a strong base. Both dissociates completely.

As we know that the pH of strong acid and strong base solution is always 7.

So, the given solution is not a buffer.

5 0

2 years ago

Colligative properties include __________ the freezing point, _____________ the vapor pressure, and ___________ the boiling poin

MrMuchimi

Colligative properties include lowering the freezing point, lowering the vapor pressure, and raising the boiling point.

7 0

3 years ago

Read 2 more answers

List the methods of separation used in water purification...... ( HELP PLEASE )

lawyer [7]

Answer:

I can list four. These are the main ones.

Bolling

Filtration

Distillation.

Chlorination

Explanation:

3 0

2 years ago

What is the empirical formula of the compound that is 25.3% magnesium and 74.7% chlorine

Margarita [4]

Answer: $MgCl_2$

Explanation:

25.3% Mg

74.7% Cl

First step: change % to g

25.3g Mg

74.7g Cl

Second step: calculate g/mol of each compound. You can do this by using the atomic mass.

$25.3gMg(\frac{1mol}{24.30g})=1.04mol$

$74.7gCl(\frac{1mol}{35.45g} )=2.11mol$

Third step: determine the lowest number and divide everything by it. Of the result, extract whole number only.

$Mg=\frac{1.04}{1.04} =1$

$Cl=\frac{2.11}{1.04}=2$

Fourth step: Write each compound with their respective number below.

This empirical formula should be: $MgCl_2$

4 0

3 years ago