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3 years ago

How many neutrons does element X have if its atomic number is 26 and its mass number is 76

1 answer:

8 0

Mass number is the total number of protons and neutrons and atomic number is the number of neutrons.

So you just subtract

Mass number - atomic number = neutrons
(Prot + neut) (Protons)

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Calculate the molarity of a solution that contains 200 g of copper (II) chloride( CuCl2) in 150 mL of solution.

Yuliya22 [10]

I think it’s letter C or D

7 0

3 years ago

What is the enthalpy in KJ of reaction for the initial combustion if the delta H for vaporization is 75.75 KJ and the net delta

Gnesinka [82]

Answer:

-775.75

Explanation:

4 0

3 years ago

6) (a) Calculate the absorbance of the solution if its concentration is 0.0278 M and its molar extinction coefficient is 35.9 L/

Anvisha [2.4K]

Answer:

6) (a) 0.499; (b) 31.7 %

7) 0.15

Explanation:

6) (a) Absorbance

Beer's Law is

$A = \epsilon cl\\A = \text{35.9 L&\cdot$mol$^{-1}$cm$^{-1}$} $\times$ 0.0278 mol$\cdot$L$^{-1} \times $ 0.5 cm = \mathbf{0.499}$

(b) Percent transmission

$A = \log {\left (\dfrac{1}{T}}\right)}\\\\\%T = 100T\\\\T = \dfrac{\%T}{100}\\\\\dfrac{1}{T} = \dfrac{100 }{\%T}\\\\A = \log \left(\dfrac{100 }{\%T} \right ) = 2 - \log \%T\\\\0.499 = 2 - \log \%T\\\\\log \%T = 2 - 0.499 = 1.501\\\\\%T = 10^{1.501} = \mathbf{31.7}$

7) Absorbance

$A = \log \left (\dfrac{I_{0}}{I} \right ) = \log \left (\dfrac{I_{0}}{0.70I_{0}} \right ) = \log \left (\dfrac{1}{0.70} \right ) = -\log(0.70) = \mathbf{0.15}}$

8 0

3 years ago

A sample of neon gas occupies 105 L at 27°C under a pressure of

Viefleur [7K]

Answer: Volume occupied by given neon sample at standard condition is 123.84 L.

Explanation:

Given: $V_{1}$ = 105 L, $T_{1} = 27^{o}C = (27 + 273) K = 300 K$ , $P_{1}$ = 985 torr

At standard conditions,

$T_{2}$ = 273 K, $P_{2}$ = 760 K, $V_{2}$ = ?

Formula used to calculate the volume is as follows.

$\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}$

Substitute the values into above formula as follows.

$\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}\\\frac{985 torr \times 105 L}{300 K} = \frac{760 torr \times V_{2}}{273 K}\\V_{2} = \frac{94116.75}{760} L\\= 123.84 L$

Thus, we can conclude that volume occupied by given neon sample at standard condition is 123.84 L.

8 0

3 years ago

Help me answer this chemistry question. thank you!

Vladimir79 [104]

Answer:

Chlorine and bromine

Explanation:

I think thats the answer in your question

8 0

3 years ago