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kifflom [539]
3 years ago
7

True or False? A day is about 12 hours long

Chemistry
1 answer:
7nadin3 [17]3 years ago
7 0

Answer:

false it's 24 hours long.

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Which statement about the alkali metals is correct?
icang [17]

Answer:

Sofia the firstttdbshsgshaksus

5 0
3 years ago
Please give formulas of how you solved I only need help on a but if you can do all that I would appreciate that.​
cricket20 [7]

Answer:

3.1 moles of ammonia

18.67× 10²³ molecules

Mass = 52.7 g

Explanation:

Given data:

Number of atoms of hydrogen = 5.68×10²⁴ atoms

A) Number of molecules of ammonia = ?

Solution:

First of all we will calculate the number of moles of hydrogen.

1 mole = 6.022× 10²³ atoms

5.68×10²⁴ atoms × 1 mol / 6.022× 10²³ atoms

0.94×10¹ mol

9.4 moles of hydrogen

Moles of ammonia:

3 moles of hydrogen are present in one mole of ammonia.

9.4 moles of hydrogen = 1/3×9.4 =

3.1 moles of ammonia

Number of molecules of ammonia:

1 mole contain 6.022× 10²³ molecules.

3.1 mol × 6.022× 10²³ molecules / 1 mol

18.67× 10²³ molecules

c) Mass of sample = ?

Mass = number of moles × molar mass

Mass = 3.1 moles × 17 g/mol

Mass = 52.7 g

4 0
3 years ago
Explain how the information given below could be used to determine the concentration of an unknown sample.
Vika [28.1K]

Answer:

See below

Explanation:Plot the known concentrations and adsorbance data.  Draw a best fit line through thwe points.  When the absorbance of a solution of unknown concentration (but same substance) is determined, find the concentration from the line at that absorption value.  See attached graph.

E.g., an sample of the same substance had an absorbance of 0.35.  Find that on the x scale and then determine the concentration that would be required to produce that level of absorbance.  0.483M in this case.

8 0
2 years ago
PLEASE HELP QUICK!!! Electromagnetic Spectrum Activity Worksheet
Vlad1618 [11]

Answer:

The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 10²⁵ hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. There is no known limit for long wavelengths, while it is thought that the short wavelength limit is in the vicinity of the Planck length. Extreme ultraviolet, soft X-rays, hard X-rays and gamma rays are classified as ionizing radiation as their photons have enough energy to ionize atoms, causing chemical reactions. Exposure to these rays can be a health hazard, causing radiation sickness, DNA damage and cancer. Radiation of visible light wavelengths and lower are called nonionizing radiation as they cannot cause these effects.

Explanation:

6 0
3 years ago
Write the mole ratios of (2ca+o2➡2cao)
tresset_1 [31]
N(Ca)/2 = n(O)/1 = n(CaO)/2

The calcium and the Calcium Oxide are divided by 2 because of their coefficients
there is no number in front of the oxygen so it is over one.
Hope this helped!!
6 0
3 years ago
Read 2 more answers
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