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2 years ago

Which of the following is not a symbol of an element? a. Na b. CO c. S d. He

1 answer:

5 0

CO is not an element because CO is a Compound. Elements contain One capital and one lowercase letter. While Compounds contain two or more capital letters.

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The longest wavelength of light with enough energy to break the Cl-Cl bond in Cl2(g) is 495 nm.

Katen [24]

Explanation:

The longest wavelength of light with enough energy to break the Cl-Cl bond = 495 nm = $495\times 10^{-9} m$

1) The frequency of the light:

$\lambda =495\times 10^{-9} m$

$\nu=\frac{c}{\lambda }$

c = speed of light= $3\times 10^8 m/s$

$\nu=\frac{3\times 10^8 m/s}{495\times 10^{-9} m}$

$=6.0606\times 10^{14) s^{-1}$

The frequency of the light is $6.0606\times 10^{14) s^{-1}$ .

2)The energy of a photon of the light:

The energy of the photon is given by : E

$E=h\nu$

h = Planck's constant = $6.626\times 10^{-34} J/s$

$E=6.626\times 10^{-34} J/s\times 6.0606\times 10^{14) s^{-1}$

$=4.016\times 10^{-19} J$

The energy of a photon of the light is $4.016\times 10^{-19} J$ .

3) The minimum energy of the Cl-Cl bond :

To break single bond of Cl-Cl bond we need energy E= $4.016\times 10^{-19} J$

1 mole = $N_A=6.022\times 10^{23} mol^{-1}$

So, in order to break 1 mole of Cl-Cl bond we will need:

$E\times N_A=4.016\times 10^{-19} J\times 6.022\times 10^{23} mol^{-1}$

$=241,828.92 J/mol=241,828.92\times 0.001 kJ/mol=241.83 kJ/mol$

The minimum energy of the Cl-Cl bond is 241.83 kJ/mol.

3 0

2 years ago

Please help me out if your good at science:)ill mark brainliest if correct

ycow [4]

D. Helps diagnose health problems

6 0

2 years ago

Bacteria consume other organisms for food, making them heterotrophs. True or False?

11111nata11111 [884]

Answer:

I would say true!

Explanation:

5 0

2 years ago

7.7 cm<br> 9.8 cm<br> 0.00<br> 0.162 m

eimsori [14]

Answer:

Volume = 1222.5cm³

Explanation:

<em>If the question is about the volume of the rectangle:</em>

The volume of a rectangle is obtained by the multiplication of its 3 dimensions: Length, width, height.

In the problem, the length of the rectangle is 0.162m = 16.2cm

The width is 7.7cm

And the height is 9.8cm

The volume is:

Volume = 16.2cm*7.7cm*9.8cm

<h3>Volume = 1222.5cm³</h3>

5 0

2 years ago

How would you prepare 250 mL of 0.125 M HCl from concentrated HCl (aq) that is 38.0% by mass with a density of 1.19 g/mL

hoa [83]

<h2>Step 1 : Identify the given </h2>

Volume = 250mL

Density = 1.19 g/ML

<h2>Step 2 . Calculate the mass of HCL </h2>

Density = mass/volume

∴Mass = Density * Volume

= 1.19g/mL* 250mL

= 297,5g

<h2>Step 3 : Calculate the total mass of the solution, given that concentration HCL is 38% </h2>

Mass of the total solution can be calculated by the following :

38% = Mc /297.5 * 100

Mc = 38/100 *297.5

= 113.05grams

• Finally, this means that mass of the total solution of 0.125M HCL i,s 113grams, ,you would use this mass to prepare 250 mL of 0.125 M HCl from concentrated HCl (aq) that is 38.0%

6 0

9 months ago