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3 years ago

If you have 23.8g of CaCl2, how many formula units is it?

Chemistry

1 answer:

NemiM [27]3 years ago

8 0

Answer:

1.3×10²³ formula unit

Explanation:

Given data:

Mass of CaCl₂ = 23.8 g

Number of formula unit = ?

Solution:

Number of moles = mass/molar mass

Number of moles = 23.8 g/110.98 g/mol

Number of moles = 0.21 mol

1 mole of any substance contain 6.022×10²³ formula unit

0.21 mol × 6.022×10²³ formula unit / 1mol

1.3×10²³ formula unit

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A patient needs to take 625 mg of ibuprofen twice daily. The pills in the bottle are each 250. mg. How many pills does the patie

WINSTONCH [101]

2 and a half
250 x 2 =500
250/2=125
and 125 is a half of 250
so your answer is
2 and a half

5 0

3 years ago

Read 2 more answers

Susan needs to simplify the expression shown below what should be her first step

Digiron [165]

Susan should follow PEMDAS,

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction,

So, the first step should be, to solve the equation in the parentheses.

I hope this helps!

5 0

3 years ago

A first-order reaction (A → B) has a half-life of 25 minutes. If the initial concentration of A is 0.900 M, what is the concentr

Oksanka [162]

Answer:

0.6749 M is the concentration of B after 50 minutes.

Explanation:

A → B

Half life of the reaction = $t_{1/2}=25 minutes$

Rate constant of the reaction = k

For first order reaction, half life and half life are related by:

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{25 min}=0.02772 min^{-1}$

Initial concentration of A = $[A]_o=0.900 M$

Final concentration of A after 50 minutes = $[A]=?$

t = 50 minute

$[A]=[A]_o\times e^{-kt}$

$[A]=0.900 M\times e^{-0.02772 min^{-1}\times 50 minutes}$

[A] = 0.2251 M

The concentration of A after 50 minutes = 0.2251 M

The concentration of B after 50 minutes = 0.900 M - 0.2251 M = 0.6749 M

0.6749 M is the concentration of B after 50 minutes.

7 0

3 years ago

In an isothermal gas chromatography experiment using an ECD detector, 1.69 nmols of nchlorohexane, C6H13Cl, was added as an inte

prohojiy [21]

Answer:

The amount of Chlorodecane in the unknown is 0.105nmols

Explanation:

a) Since the GC is in an isothermal state, Chlorohexane C6H13Cl (1.69 nmols) because of its lower boiling point will elute first and Chlorodecane C12H21Cl will elute second.

The area of the first peak corresponding to Chlorohexane is 32434 units.

The area of the second peak corresponding to chlorodecane is 2022 units.

Since the response factor of the compound is not given in question and considering the response factor is same for both the compounds, the answer will be as follow:

1.69 nmols of Chlorohexane gives 32434 units

How much of chlorodecane gives 2022 units

By cross multiplication;

Moles of Chlorodecane = 2022*1.69/32434

=0.105nmols

4 0

3 years ago

What happens to an object at rest if balanced forces act upon it?

OLga [1]

Newton's first law of motion states that an object at rest will remain at rest unless an unbalanced force acts on it. If you apply balanced forces on the object there would be no net force. The body does not accelerate but instead stays at rest.

Another way to look at this problem is to use Newton's second law of motion. The first law states that $F = m\times a$ , where $a$ is the acceleration $F$ is the net force and $m$ is the mass of the object.

When F is zero, the acceleration of the object is zero. This means that if the object had a velocity of zero before the balanced forces started acting, the velocity will stay at zero after the balanced forces begin to act. If the object was moving at a constant velocity before the balanced forces started acting on it, it would continue at that constant velocity after the balanced forces begin to act.

4 0

3 years ago