If you have 128 atoms of a radioactive substance, with a half-life of 31 seconds, how many atoms would remain after 62 seconds? Please show your work.
Answer:
N = 32 atoms
Explanation:
The radioactive elements decays as follows:
Ln (N/N₀) = -kt
Where N are number of atoms after t time, N₀ are initial number of atoms, k is decay constant in time⁻¹
We can obtain k from t(1/2):
k = ln 2 / t(1/2)
k = 0.02236s⁻¹
Ln (N/128 atoms) = -0.02236s⁻¹*62s
(N/128 atoms) = e^-1.386
N/128 atoms = 0.25
N = 128 atoms * 0.25
N = 32 atomsOn what is the geological time scale based?
A: changes in climate and historical records
B: geological and biological events
C: geological events
D: evolutionary events
Answer: The answer is b for sure
Explanation: Because, I took the test
interview at least three farmers in your community. ask them how they prepare their field for planting vegetable crops.And the common tools, implements and equipment they used in preparing for planting
Answer:
I think they use water,shovel,and rake.
Explanation:I was in ag in 8th grade and first we used a rake and raked all the stuff up. Then we waterd the dirt. Then dug a hole and planted the plant and waterd it after.
I hoped this help have a nice day! Comment if you need more help.
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How many grams of barium chloride (BaCl2) are there in 0.187 mol?
0.187 mol
Answer:
38.9 grams of [tex]BaCl_2[/tex]
Explanation:
0.187 mol BaCl2 x [tex]\frac{208 g}{1 mol}[/tex]
0.187 m x 208 g/m
0.187 x 208 g
38.896 g --> 38.9 g BaCl2
Which phrase describes a gas?
A fixed shape and volume
B changing shape and volume
C changing shape and fixed volume
D fixed shape and changing volume
Which part of the wave does the arrow point to?
A. Rarefaction
B. Crest
C. Frequency
D. Trough
Help me ASAP please
Answer:
B
Explanation:
It was the correct answer when I answered it
The part of the wave that the arrow is pointing to is the crest.
Wave is defined as a disturbance that travels through a medium and transfers energy from one point to another without causing any permanent displacement of the medium itself.The given diagram is a waveform. The waveform consists of a crest and a trough. The trough is the minimum amplitude of the waveform while the crest is the maximum amplitude of the waveform From the graph, the red dots are the crest of the graph while the blue dots are the trough.Hence we can conclude that the part of the wave that the arrow is pointing to is the crest.
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Is the following equation balanced? Why or why not?
N, + 6H2 → 2NHO
Answer:
No
Explanation:
There is only one Nitrogen on the left side while there are 2 on the right. Also there is zero oxygen on the left side and two on the right. The amounts of hydrgen arent equal to each side either.
does sodium chloride retain any characteristic of sodium or chlorine?
Answer:
When this occurs, sodium will donate an electron (which is a negatively-charged particle) to chlorine. This makes sodium slightly positive and chlorine slightly negative. Opposite charges attract, right? So then, sodium ions will attract chloride ions and form an ionic bond.
Explanation:
Which conclusion about the chemical reactivity of these elements is valid? Boron is the most reactive because it has the most protons. Fluorine is the most reactive because it has 7 electrons in the outer shell. Silicon is the most reactive because it has an equal number of protons and neutrons. Gallium is the most reactive because it has many more neutrons than protons.
Answer:
Fluorine is the most reactive because it has 7 electrons in the outer shell. The conclusion of this element's chemical reactivity is valid .
Explanation:
Among all the given elements - Boron ,Fluorine , Silicon and Gallium , Fluorine is the most reactive element because it has 7 electrons in the outer shell. It has a very small size and only requires one electron to get into a stable configuration with that of noble gases. Thus, to reach that stable state, they react spontaneously with elements, leading to its high reactivity.
Therefore, most reactive elements are in the halogen band, and none of the other three elements called Boron, Silicon and Gallium belong to the halogen group.
Hence, the correct answer is B (fluorine is the most reactive because it has 7 electrons in the outer shell).
What is the approximate mass of one proton?__amu; and the approx. mass of a neutron?___amu
Answer:
I don't have an answer but did you ever get it?
Explanation:
I need help.
A tea bag in a cup of hot water can be a simple model of a cell. Water moves into the tea bag and substances in the tea leaves move out through a thin layer of material. What does the thin material that holds the tea leaves represent?
Answer:
It represents a partially permeable membrane
Explanation:
As the water is added to the teabag it causes the tea leaves to move and triggers diffusion of the leaves. ... The addition of heat (from the hot water) to the tea bag causes its molecules to move much faster than at room temperature
Answer:
The cell membrane
Explanation:
I checked it and it’s right on A P E X. I hope this helps!!
Proof:
How did the composition of elements in the universe change over time?
Please help!
Will mark brainliest! :)
Answer: According to NASA, after inflation the growth of the universe continued, but at a slower rate. As space expanded, the universe cooled and matter formed. One second after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons and neutrinos.
Explanation:Hopefully this helps!
An atom has 8 protons, 9 Neutrons, and 10 electrons. What is the mass number?
Answer:
17
Explanation:
Mass number = # of protons + # of neutrons
Mass number is calculated using ONLY protons and neutrons. Electrons are not in the count.
Thus, we simply add them together: 8 + 9 = 17
This element is Oxygen - 17.
Which rocky planets is the most different to Earth's? Why? mark you as brainlist
Mercury, Venus, and Mars are all rocky planets. None are more or less different than Earth. Earth is the largest and the only planet with extensive regions of liquid water.
Explanation:
Answer:
En nuestro sistema solar, hay cuatro planetas terrestres, que también son los cuatro más cercanos al sol: Mercurio, Venus, Tierra y Marte. Durante la formación del sistema solar, probablemente hubo más planetoides terrestres, pero se fusionaron entre sí o fueron destruidos.
Which of these substances will NOT stop iron from rusting?
Answer:
u didn't list anything
Explanation:
buh water and oxygen forming hydrated iron
Which material has a density most similar to the density of water?
( Theres more then one answer)
A) Rubber
B) Wooden ball
C) Ice
D) Egg
E) Granite
F) Titanium
Answer:
b
Explanation:
Option a, c and d are correct.
The following information should be considered;
Density shows the relationship between the mass and volume. Thr rubber, egg and ice should have the same density that equivalent to the water density. But for the other options, it is not equivalent to each other.learn more: https://brainly.com/question/15959704?referrer=searchResults
5. One of Dr. Birdley's boxes has a
volume of 120 cm' and a mass of 2400 g.
The density of the rock is
a) 20 g/cm
b) 2520 g/cm
c) 240,480 g/cm
d) 2280 g/cm
Answer:
a.20g/cm
hope this helps :)
Explanation:
Ocean waves are limited in
Answer:
are there answer choices with the question?
Explanation:
sorry im a little confused
In what ways is a sodium atom different from a sodium ion? *
what information does the spectrum give about the source of the element?
Answer:
A continuous spectrum can identify elements by the presence of dark bands, and it also tells scientists how hot the object is: As the temperature goes up, the spectrum has increasing amounts of green, blue and violet colors. Relatively cool objects have a spectrum that has mostly deep red or red and yellow.
Explanation:
What’s the answer????
Answer:
all of above
Explanation:
Explain what it means for energy to be conserved.
To solve this we must be knowing each and every concept related to conservation of energy. Therefore, in the below given ways we can define conservation of energy.
What is conservation of energy?Energy conservation may be defined simply as the process of consuming less energy. Energy conservation also entails changing behaviors and routines to consume less energy.
Consumers can gain from energy saving in terms of the economy and the environment. Energy conservation has several advantages for the environment, including cheaper energy prices.
Conserving energy can also help prevent the extinction of plants and animals. Start energy conservation right away if you wish to exist in a healthier and happier society.
Therefore, in the above given ways we can define conservation of energy.
To know more about conservation of energy, here:
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which elements have similar chemical properties
A) Na, K, Mg
B) B, Al, S
C) N, O, F
D) He, Ar, Kr
What type of hydrocarbons are called praffins?
Answer:
saturated hydrocarbons are called paraffin:)
A chemical change happens because the particles and chemical bonds that make up the substance get rearranged. true or false
Answer:
True
Explanation:
In a chemical reaction the hydrogen bonds between the atoms in a substance break up to form a new one.
A _____ state is when the electron is closest to the nucleus.
Answer:
ground state
Explanation:
A ground state is when the electron is closest to the nucleus.
What is the ground state of an atom?The ground state of an electron is the state of the lowest energy for that electron. The nucleus is surrounded by electrons that occupy orbitals of varying energy levels.
When an electron jumps to an energy state greater than its ground state, then it is in an excited state. An electron can become excited from the ground state to the excited state if it is given extra energy in the form of a photon, or packet of light.
An electron occupies the lowest energy level that is closer to the nucleus when the electron is present in the ground state.
Learn more about the ground state of an atom, here:
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Askin cell divides to make a new skin cell. Which component of cell theory does this best illustrate?
O All living things are made of cells.
O Cells are the basic unit of structure and function of all living things.
O All cells come from other cells.
O Cells are generated from nonliving materials.
Answer:
all cells come from other cells
How does gravity affect your everyday lives?
Answer:
gravity's is why I can sit or jump and not fly into space and is why we have a atmosphere. basically gravity is why my daily life even exist.
Explanation:
Answer:
Gravity keeps us grounded. it helps us everyday just to stay on the ground. If we didnt have gravity we would just flout away.
What causes tectonic plates to move?
A. When the mantle moves, the plates move.
B. When the inner core moves, the plates move.
C. When the outer core moves, the plates move
Hello, please help me if you can :(
Answer:
4ml
Explanation: