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3 years ago

How are the terms group and period used on the periodic table

1 answer:

5 0

Periods go left to right or horizontally. Groups are a name for the vertical columns in a periodic table. Each column is called a group. The elements in each group have the same number of electrons in the outer orbital.

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A wave like the one shown in the diagram below is called a transverse wave. Such a wave is typical of light waves and other type

raketka [301]

Answer: transmits yellow light

Explanation:

5 0

3 years ago

Given the molar absorptivity for a species X of 1600 M-1cm-1 at a wavelength of 270 nm, and 400 M-1cm-1 at a wavelength of 540 n

Andre45 [30]

Answer:

Explanation:

From the given information:

At wavelength = 270 nm

$\varepsilon x_1 = 1600 \ m^{-1} \ cm^{-1} \\ \\ \varepsilon y_1 = 200 \ m^{-1} \ cm^{-1}$

At 270 nm

Suppose x is said to be the solution for the concentration of x and y to be the solution for the concentration of y;

Then:

$\varepsilon x_1 \ l + \varepsilon y_1 \ l= 0.5 \\ \\ A = A_1 + A_2$

$1600 xl + 200 yl= 0.5$

Divide both sides by 200

$8xl + yl = \dfrac{0.5}{200}$

$8x + y = \dfrac{0.5}{200}l$

Use l = 1cm (i.e the standard length)

Then;

$8x + y = \dfrac{0.5}{200} ---- (1)$

$\varepsilon x_2 x \ l + \varepsilon y_2 y \ l= 0.5 \\ \\ 40 xl + 800 yl = 0.5$

$x + 20 y = \dfrac{0.5}{400 \ l}$

since l = 1

$x + 20 y = \dfrac{0.5}{400 \ } --- (2)$

Equating both (1) and (2) together, we have:

$8x + y - 8x - 160 y = \dfrac{0.5}{200} - \dfrac{0.5 \times 8}{400} \\ \\ \implies - 159 y = \dfrac{0.5}{200} ( 1 - \dfrac{8}{2}) \\ \\ -159 y = \dfrac{-0.5 \times 3}{200} \\ \\ 159 \ y = 0.0075 \\ \\ y = \dfrac{0.0075}{159} \\ \\ y = 0.00004716 \\ \\ y = 4.7 \times 10^{-5 } \ M$

3 0

3 years ago

Which answer helps to explain why carbon atoms tend to make 4 covalent bonds? which answer helps to explain why carbon atoms ten

Kay [80]

Carbon-12 has the following electron configuration: 1s2-2s2-2p2. As seen in the configuration, the right answer is: the first electron shell has 4 orbitals.

8 0

3 years ago

Read 2 more answers

A gas has a volume of 62.65L at O degrees Celsius and 1 atm. At what temperature in Celsius would the volume of the gas be 78.31

Anastaziya [24]

Answer:

The volume of the gas will be 78.31 L at 1.7 °C.

Explanation:

We can find the temperature of the gas by the ideal gas law equation:

$PV = nRT$

Where:

n: is the number of moles

V: is the volume

T: is the temperature

R: is the gas constant = 0.082 L*atm/(K*mol)

From the initial we can find the number of moles:

$n = \frac{P_{1}V_{1}}{RT_{1}} = \frac{1 atm*62.65 L}{(0.082 L*atm/K*mol)*(0 + 273)K} = 2.80 moles$

Now, we can find the temperature with the final conditions:

$T_{2} = \frac{P_{2}V_{2}}{nR} = \frac{612.0 mmHg*\frac{1 atm}{760 mmHg}*78.31 L}{2.80 moles*0.082 L*atm/(K*mol)} = 274.7 K$

The temperature in Celsius is:

$T_{2} = 274.7 - 273 = 1.7 ^{\circ} C$

Therefore, the volume of the gas will be 78.31 L at 1.7 °C.

I hope it helps you!

8 0

3 years ago

Yasmin's teacher asks her to make a supersaturated saline solution. Her teacher tells her that the solubility of the salt is 360

Aleks [24]

Answer:

She can add 380 g of salt to 1 L of hot water (75 °C) and stir until all the salt dissolves. Then, she can carefully cool the solution to room temperature.

Explanation:

A supersaturated solution contains more salt than it can normally hold at a given temperature.

A saturated solution at 25 °C contains 360 g of salt per litre, and water at 70 °C can hold more salt.

Yasmin can dissolve 380 g of salt in 1 L of water at 70 °C. Then she can carefully cool the solution to 25 °C, and she will have a supersaturated solution.

B and D are wrong. The most salt that will dissolve at 25 °C is 360 g. She will have a saturated solution.

C is wrong. Only 356 g of salt will dissolve at 5 °C, so that's what Yasmin will have in her solution at 25 °C. She will have a dilute solution.

3 0

3 years ago

Read 2 more answers