1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
HACTEHA [7]
3 years ago
13

Which of the following is a source of chemical energy commonly used by humans? A. water flowing in a river B. a bicycle C. a san

dwich D. turning on a lightswitch
Chemistry
1 answer:
ziro4ka [17]3 years ago
7 0

Answer:

Option C sandwich is the correct option

You might be interested in
Ice, liquid, and water vapor are the three states of water
UNO [17]
This is true. Solid, Liquid, and Gas.


Hope that helps!!
7 0
3 years ago
3- AR 385-63/MCO 3570.1C is used in conjunction with
Rasek [7]
AR 385-63/MCO 3570.1C is used in conjunction with DA PAM 385-63.
AR 385-63/MCO 3570.1C is the regulation or order which provides revised range safety policy for the Army and Marine Corps.
This order/regulation applies on the Active Army or the Army National Guard of the United states.
8 0
3 years ago
determine the frequency and wavelength (in nm) of the light emitted when the e- fell from n=4 and n=2
Lostsunrise [7]

Answer:

Frequency = 6.16 ×10¹⁴ Hz

λ = 4.87×10² nm

Explanation:

In case of hydrogen atom energy associated with nth state is,

En =  -13.6/n²

For n = 2

E₂ = -13.6 / 2²

E₂ = -13.6/4

E₂ = -3.4 ev

Kinetic energy of electron = -E₂ = 3.4 ev

For n = 4

E₄ = -13.6 / 4²

E₄ = -13.6/16

E₄ = -0.85 ev

Kinetic energy of electron = -E₄ = 0.85 ev

Wavelength of radiation emitted:

E = hc/λ = E₄ - E₂

hc/λ = E₄ - E₂

by putting values,

6.63×10⁻³⁴Js × 3×10⁸m/s / λ = -0.85ev   - (-3.4ev )

6.63×10⁻³⁴ Js× 3×10⁸m/s / λ = 2.55 ev

λ = 6.63×10⁻³⁴ Js× 3×10⁸m/s  /2.55ev

λ = 6.63×10⁻³⁴ Js× 3×10⁸m/s  /2.55× 1.6×10⁻¹⁹ J

λ = 19.89 ×10⁻²⁶ Jm / 2.55× 1.6×10⁻¹⁹ J

λ = 19.89 ×10⁻²⁶ Jm / 4.08×10⁻¹⁹ J

λ = 4.87×10⁻⁷ m

m to nm:

4.87×10⁻⁷ m ×10⁹nm/1 m

4.87×10² nm

Frequency:

Frequency = speed of electron / wavelength

by putting values,

Frequency = 3×10⁸m/s /4.87×10⁻⁷ m

Frequency = 6.16 ×10¹⁴ s⁻¹

s⁻¹ = Hz

Frequency = 6.16 ×10¹⁴ Hz

3 0
3 years ago
What number of atoms of phosphorus are present in 1.00g of each of the compounds in exercise 40?
ira [324]

Answer:

Answer: 1.095 * 10^22 atoms of P.

Explanation:

3 0
3 years ago
When do epa’s refrigerant management regulations exempt refrigerant from the venting prohibition
Xelga [282]

The Environmental Protection Agency (EPA) refrigerant management regulations would exempt any refrigerant from venting problem when it determines that the refrigerant in an appliance do not pose a threat to the environment (surrounding) if released.

A refrigerant can be defined as any chemical substance that undergoes a phase change (liquid and gas) so as to enable the cooling and freezing of materials. They are typically used in air conditioners, refrigerators, water dispensers, etc.

In the United States of America, the Environmental Protection Agency (EPA) is a governmental agency which was established by U.S Congress and it is saddled with the responsibility of overseeing all aspects of pollution, environmental clean up, degradation, pesticide use, contamination, and hazardous waste spills. Also, EPA research solutions, policy development, and enforcement of regulations through the resource Conservation and Recovery Act.

Simply stated, the Environmental Protection Agency (EPA) is the governmental agency set up to ensure that various industries, factories and people comply with laws and regulations concerning the environment.

In conclusion, appliances such as a refrigerator, air conditioner (AC), etc., whose refrigerants do not pose a threat (potentially cause damage) to the environment if released are typically exempted by the EPA's refrigerant management regulations.

6 0
3 years ago
Other questions:
  • A gas has a temperature of 273.15 K and a pressure of 101.325 kPa. What can be concluded about the gas? It has reached standard
    5·1 answer
  • During an experiment, 102 grams of calcium carbonate react with an excess amount of hydrochloric acid. If the percent yield of t
    6·1 answer
  • Need help with question 1 a b and c also question 3 <br> ASAP help needed
    13·1 answer
  • The chemical formula for water is H2O2. True or False
    7·2 answers
  • What is the molecular geometry of a molecule made of two atoms that share one pair of electrons and have no lone electrons pairs
    8·1 answer
  • Electrons in Atoms
    9·2 answers
  • 108.95 g/mol, C3H2Cl2 Express your answer as a chemical formula.​
    7·1 answer
  • In which type of radioactive decay does the nucleus become more stable without changing its identity?(1 point)
    6·2 answers
  • 3. A group of inner planets are also known as------- *
    5·1 answer
  • Identify each of the following compounds as: (a) a nonelectrolyte: lactose (c12h22o11) potassium chloride (kcl) lactic acid (hc3
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!