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Serhud [2]
3 years ago
14

Total solar eclipses are common and happen every month at the beginning of the new lunar cycle.

Chemistry
1 answer:
Bogdan [553]3 years ago
7 0
False, solar eclipses happen when the moon moves between the Sun and the Earth, blocking the Sun's rays and casting a shadow on Earth. It happens about once every 18 months (on average)
You might be interested in
What is the ph of a solution of 0.50 m acetic acid?
frosja888 [35]
You need to use the Ka for the acetic acid and the equilibrium equation.

Ka = 1.85 * 10^ -5

Equilibrium reaction: CH3COOH (aq) ---> CH3COO(-) + H(+)

Ka = [CH3COO-][H+] / [CH3COOH]

Molar concentrations at equilibrium

CH3COOH         CH3COO-     H+

 0.50  - x                  x                 x

Ka = x*x / (0.50 - x) = x^2 / (0.50 - x)

Given that Ka is << 1 => 0.50 >> x and 0.50 - x ≈ 0.50

=> Ka ≈ x^2 / 0.50

=> x^2 ≈ 0.50 * Ka = 0.50 * 1.85 * 10^ -5 = 0.925 * 10^ - 5 = 9.25 * 10 ^ - 6

=> x = √ [9.25 * 10^ -6] = 3.04 * 10^ -3 ≈ 0.0030

pH = - log [H+] = - log (x) = - log (0.0030) = 2.5

Answer: 2.5
6 0
3 years ago
A student plans to add HCL to a solution containing pb(NO3)2 (aq). To determine how much Pb2+ will precipitate from solution whe
WINSTONCH [101]

Answer:

Option C. Ksp for PbCl₂

Explanation:

The equilibrium constant that is established between a solid and its ions in a saturated solution is what is known as Ksp (solubility product). It is an equilibrium constant based on concentrations.

The concentrations must be equilibrium, that is, concentrations of the ions in a saturated solution. To be sure of such saturation it is convenient to form a precipitate.

The smaller the Kps, the more insoluble the salt

5 0
3 years ago
Which element is this.Its shiny,Is solid at room temperature, has atoms with two valence electrons?A:Lithium B:Strontium C:Alumi
tatyana61 [14]

Answer:

Stronium

Explanation:

It is a metal (and shows classic physical proerties). It also belongs to the second family, meaning it has two valence electrons.

4 0
4 years ago
What characteristic frequencies in the infrared spectrum of your sodium borohydride reduction product will you look for to deter
kkurt [141]

Answer:

A)The characteristic frequency to look out for is  1720-1740 cm-1 (for C=O) for which will disappear in the end product but initially present in the reactant.

B)Characteristic frequency  present in the infrared spectrum will be at a peak of  3300-3400 cm-1 which will be due to O-H stretch.

C)If the product is wet with water there will be no change in the infrared spectrum

Explanation:

The characteristic frequency to look out for is  1720-1740 cm-1 (for C=O) for which will disappear in the end product but initially present in the reactant.

Characteristic frequency  present in the infrared spectrum will be at a peak of 3300-3400 cm-1 which will be due to O-H stretch.

If the product is wet with water there will be no change in the infrared spectrum

5 0
3 years ago
The wavelength of a given region of the electromagnetic spectrum ranges from 1 x 10-11 - 1 x 10-8 meters. Which waves are found
ss7ja [257]
The electromagnetic spectrum consists of the full range of known electromagnetic waves. And among them, X-rays has the wavelength of the region 1*10-11 to 1*10-8 meters.
5 0
3 years ago
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