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Mkey [24]
2 years ago
15

Perform the following

Chemistry
1 answer:
stepan [7]2 years ago
8 0

Answer:

.747

Explanation:

Answer can only have THREE sig dig because 12.9 has only three

9.635/12.9 = .747

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I’ll give Brainliest to the first answer
Sever21 [200]

Answer:

C. equal to, elements, products

Explanation:

I took a quiz and it said this was right

7 0
3 years ago
If 5.0 mL of a Sports Drink with an absorbance reading of 0.34 was diluted with water to 10.0 mL and was read by the colorimeter
MaRussiya [10]

Answer:

the expected absorbance of the solution = 0.17

Explanation:

From the information given:

Using Beer's Lambert Law, we have

A = ∈CL

where;

A = Absorbance

∈ = extinction coefficient

C = concentration

L = cell length

Since Absorbance is associated with concentration.

Assuming the measurement were carried out in the same solution; Then  ∈ and L will be constant and A  ∝ C ----- (1)

Let consider the concentration to be C  (mol/L)

5.0 mL of a Sports Drink = 5.0 mL × C (mol)/1000 mL

= 5C/1000 mL

was diluted with water to 10.0 mL

So, when diluted with water to 10.0 mL; we have:

The new concentration to be : \dfrac{(5 C \times 1000) \ mol }{(1000 \times 10 \times 1000)\  mL}

Since :1000mL = 1 L

The new concentration = \dfrac{C \ mol }{2 \ L}

As stated that the initial absorbance reading A_1 = 0.34

The expected absorbance reading will be A_2 = ???

From (1)

A ∝ C

∴

\dfrac{A_2}{A_1}=\dfrac{C_2}{C}

A_2 = \dfrac{A_1}{C}

A_2 = \dfrac{0.34}{2}

A_2 = 0.17

Thus ; the expected absorbance of the solution = 0.17

8 0
3 years ago
23.73 g of some metal has a volume of 3.0mL.<br> Find this metals density.
vredina [299]

Answer:

<h2>7.91 g/mL</h2>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume} \\

From the question we have

density =  \frac{23.73}{3.0}  \\

We have the final answer as

<h3>7.91 g/mL</h3>

Hope this helps you

4 0
3 years ago
A new potential heart medicine, code-named X-281, is being tested by a pharmaceutical company, Pharma-pill. As a research techni
yarga [219]

Answer:

The pKa of X-281 is 3.73.

Explanation:

X-281 is a monoprotic weak acid so that it will not dissociate completely in solution (weak acid) and will only produce 1 mol of protons per mol compound (monoprotic acid).

The dissociation equation could be written as follows:

X-281-H ⇆ X-281 + H⁺

Note the equilibrium arrows indicating that not all X-281-H dissociates at equilibrium.

Initially, the concentration of X-281-H is 0.089 M. At equilibrium, the concentration of the dissociation products, X-281 and H⁺, is unknown but both must be the same, since the drug is a monoprotic acid. We can call "X" to the concentration of the products. The concentration of X-281-H is the initial concentration minus the concentration of the products: 0.089 M - X. Then, at equilibrium, these are the concentrations of each species present:

  X-281-H               ⇆      X-281        +       H⁺

(0.089 M-X)                         X                    X

We also know that the pH is 2.40. Then:

pH = -log[H⁺] = 2.40

where [H⁺] is the molar concentration of the protons or "X". Then:

-log X = 2.40

log X = -2.40

X = 10^(-2.40) = 3.98 x 10⁻³ M

The concentration of each species present in the equilibrium is then:

[H⁺] = 3.98 x 10⁻³ M

[X-281] = 3.98 x 10⁻³ M

[X-281-H] = 0.089 M - 3.98 x 10⁻³M = 0.085 M

At equlibrium, the acidity constant Ka is:

Ka = [X-281] * [H⁺] / [X-281-H]

Ka = (3.98 x 10⁻³ M * 3.98 x 10⁻³ M ) / 0.085 M = 1.86 x 10⁻⁴

Then the pKa is:

pKa = -log Ka = -log (1.86 x 10⁻⁴) = <u>3.73</u>

7 0
4 years ago
What is the wavelength of light that has a frequency of 2.85 x 10^14 Hz [c=3.00 x 10^8]
aniked [119]

Answer:

1.05 x 10^-6

Explanation:

Lambda = c / f

f if frequency

c is intensity of light

lambda = 3 x 10^8  / 2.85 x 10^14

             = 1.05 x 10 ^-6

8 0
3 years ago
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