A 50.0- mL volume of 0.15 M HBr is titrated with 0.25 M KOH . Calculate the pH after the addition of 14.0 mL of KOH

How many atoms are there in each of the following substances?

juin [17]

To know the number of atoms, it will be necessary to use the formula of avogadro. We calculate the number of moles then we can calculate the number of avogadro.

The molar mass of:

Phosphorus = 31g / mol

Mercury = 200 g / mol

Bismuth = 209 g / mol

Strontium = 87 g / mol.

The number of avogadro (N) is 6.023 10 ^ 23

n = m (mass) / M (molar mass)

number of atoms = n. N = m / M . N

number of phosphorus atoms = 5.14/31 . 6.023 10^23 = 9.98 10 ^ 22 atoms

Number of atoms of mercury = 2.16/200 . 6.023 10^23 = 6.5 10 ^ 21 atoms

Number of bismuth atoms = 1.8/209 . 6.023 10^23 = 5.18 10 ^ 21 atoms

Number of strontium atoms = 8.8 x 10-2 /87 . 6.023 10^23 = 6.09 10 ^ 20 atoms

3 0

3 years ago

A beaker has a mass of 77.275 calculate this mass in mg

Rainbow [258]

By definitions of the prefixes in the metric system, the prefix milli- (abbreviated as m as in mg) indicates 1/1000 or 1 x 10^-3 of a gram. In this case, if a beaker has a mass of 77.275 g (I am assuming this is grams since most other units would make it too heavy or too light), we would multiply this by 1000 to convert it to milligrams. So 77.275 g = 77,275 mg.

4 0

3 years ago

How many moles are in 1.93x1023 particles of Na3PO4?

Tresset [83]

Answer:

<h3>The answer is 0.32 moles</h3>

Explanation:

To find the number of moles given the number of entities we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question

N = 1.93 × 10²³ particles

We have

$n = \frac{1.93 \times {10}^{23} }{6.02 \times {10}^{23 } } \\ = 0.320598006...$

We have the final answer as

<h3>0.32 moles</h3>

Hope this helps you

6 0

3 years ago

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Am I correct? (Plz don’t used this for points or typing random things…plz don’t)

zhuklara [117]

Answer:

The answers are A, C, & D.

4 0

3 years ago

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How do chemical systems at equilibrium respond to changes in pressure, temperature, and concentration?

kodGreya [7K]

Answer:

...when the pressure is high the equilibrium increases but when its low equilibrium decreases also in temperature the higher the temperature the high the equilibrium and viceversa is true but also in concentration its the same case

3 0

3 years ago