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3 years ago

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Which ancient African Kingdom is located in western Africa?

1 answer:

NISA [10]3 years ago

3 0

Answer:

Ghana Empire is was a kingdom in western Africa.

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Calculate the density of an object with a mass of 6.147 and a volume of 9.3 (include units)

Olin [163]

Here is the formula for density:
Density (D) = Mass (M) divided by Volume (V)

So you would do D = 6.147 divided by 9.3

As an as answer you would get: 0.6609677419g/cm^3

Additional information:

The formula for volume is:
V = M divided by D

The formula for Mass is:
M = D times V

I hope this helps :)

5 0

3 years ago

What is the pH of a KOH solution that has [H ] = 1. 87 × 10–13 M? What is the pOH of a KOH solution that has [OH− ] = 5. 81 × 10

vlada-n [284]

pH is the hydrogen ion concentration and pOH is the hydroxide ion concentration in the solution. pH KOH is 12.73, pOH KOH is 2.24 and pH NaCl is 7.

<h3>What are pH and pOH?</h3>

pH is the negative log of the hydrogen ion concentration and pOH is the negative log of the hydroxide ion concentration.

The relation between the pH and pOH can be given as, $\rm pOH = 14 - pH$

The pH of KOH can be calculated by the formula,

$\rm pH = \rm -log [H^{+}]$

In the first case, the concentration of the KOH is $1. 87 \times 10^{-13}\;\rm M$

Substituting values in the equation:

$\begin{aligned} \rm pH &= \rm -log [H^{+}]\\\\&= \rm -log [1. 87 \times 10^{-13}\;\rm M ]\\\\&= 12.73\end{aligned}$

Hence, the pH of KOH is 12.73.

<u />

pOH of KOH can be calculated by the formula,

$\rm pOH = \rm -log [OH^{-}]$

The hydroxide concentration of the KOH solution is $5. 81 \times 10^{-3}\;\rm M$

Substituting value in the equation:

$\begin{aligned} \rm pOH &= \rm -log [OH^{-}]\\\\&= \rm -log [5. 81 \times 10^{-3}\;\rm M ]\\\\&= 2.24 \end{aligned}$

Hence, the pOH of KOH is 2.24

<u />

The pH of NaCl can be calculated by the formula,

$\rm pH = \rm -log [H^{+}]$

In the third case, the concentration of the NaCl is $1. 00\times 10^{-7}\;\rm M$

Substituting values in the equation:

$\begin{aligned} \rm pH &= \rm -log [H^{+}]\\\\&= \rm -log [1. 00 \times 10^{-7}\;\rm M ]\\\\&= 7 \end{aligned}$

Hence, the pH of KOH is 7.0.

Therefore, KOH is basic and NaCl is approximately neutral.

Learn more about pH and pOH here:

brainly.com/question/13885794

3 0

2 years ago

Robert has 4 grams of a substance and Jill has 10 grams of the same substance. Which of the following statements is true?

ELEN [110]

If Robert has 4 grams of a substance and Jill has 10 grams of the same substance <span>Jill's sample will weigh more than Robert's sample.</span>

5 0

3 years ago

Read 2 more answers

Which of these is an indication that a chemical reaction has occurred?

nevsk [136]

Formation Of A Gas.

3 0

3 years ago

What feature of a chemical equation is used to balance the equation and make sure it obeys the law of conservation of mass?

taurus [48]

Answer:

b) coefficient

Explanation:

Refer to this example:

CH4 +2 O2 → CO2+ 2 H2O

2 is used as a coefficient in this chemical equation.

5 0

2 years ago

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