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
Nostrana [21]
2 years ago
5

The periodic table is based on an element's

Chemistry
2 answers:
uranmaximum [27]2 years ago
7 0

The correct answer is:

B.  atomic number.


Stels [109]2 years ago
4 0
The answer will be B.
You might be interested in
Which of the following is the best evidence for a chemical reaction?
alisha [4.7K]
C. Formation of a new substance
5 0
3 years ago
A watt is a unit of power or energy per unit time (1 W = 1 J/s). A semiconductor laser in a CD player has an output wavelength o
GREYUIT [131]

Answer:

n = 2.208x10¹⁸ photons

Explanation:

The energy of a photon( an elementary particle) is given by the equation:

E = nxhxf

Where n is the number of photons, h is plank constant (6,62x10⁻³⁴ J.s), and f is the frequency. Knowing that the power level is 0.120mW (1.2x10⁻⁴ W), the energy in J, for a time of 78 min (4680 s)

E = 1.2x10⁻⁴x4680 = 0.5616 J

The frequency of a photon is its velocity ( c= 3x10⁸ m/s) divided by its wavelength, which is 780 nm = 780x10⁻⁹ m

f = 3x10⁸/780x10⁻⁹

f = 3.846x10¹⁴ s⁻¹

Then, the number of photons is:

0.5616 = nx6,62x10⁻³⁴x3.846x10¹⁴

n = 2.208x10¹⁸ photons.

5 0
3 years ago
Three treatments of different starting materials are listed. Which statement explains the treatments? Substance 1 was activated
iren2701 [21]
<span> Substance 1 was activated by the heat and inactivated by ice, Substance 2 was activated by the change in concentration, and Substance 3 increased the surface area.</span>
8 0
3 years ago
Read 2 more answers
Why do you think there are different stars in each nighttime section of the artifact?
chubhunter [2.5K]

Answer:

The sky looks different in each nighttime section of the artifact because the artifact sections represent different seasons. ... Different constellations are visible on different nights throughout the year because of the earth's orbit. The Earth orbits around the sun. A full orbit is 365 days or one year.

Explanation:

7 0
3 years ago
Which of the following correctly applies to a catalyst? a. They do not actually participate in the chemical reaction and therefo
lawyer [7]

Answer: option B) They provide an alternate lower energy mechanism by which the reaction proceeds

Explanation:

Catalyst are involved in chemical reaction increasing the rate they occur by lowering the activation energy found in the bound- reactants complex.

The reaction moves forward because the lower energy mechanism when catalyst are added allows for a more easily splitted bond, thus, allowing the formation of products.

6 0
2 years ago
Other questions:
  • If a Geiger counter that is 1 m away from a small source reads 50 counts per minute, what will its reading be 2 m from the sourc
    9·2 answers
  • Consider the reaction between reactants s and o2: 2s(s)+3o2(g)→2so3(g)if a reaction vessel initially contains 7 mols and 9 mol o
    13·1 answer
  • I need a science fair topic and the science fair is in 3 days
    11·2 answers
  • I have a block of gold and the density is 13.54g/ml If I cut the block in half what is the density of the smaller pieces of gold
    13·1 answer
  • what do the symbols tell you about the conditions of the reaction shown to the right check all boxes that apply
    13·2 answers
  • Select the correct answer.<br> Which characteristic is a property of water?
    14·1 answer
  • Magnesium carbonate decomposes on heating to form magnesium oxide and carbon dioxide as shown.
    13·1 answer
  • Calculate the energy required to freeze 378 grams of water to ice at 0°c​
    11·2 answers
  • Which are charateristics of all metals
    5·2 answers
  • A substance that has a pH = 7 is a/an
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!