Answer:
Amount left after 140 days is 38.125 g.
Explanation:
Given data:
Half life of Co-59 = 35 days
Total mass of sample = 610.0 g
Sample remain after 140 days = ?
Solution:
Number of half lives passes during 140 days:
Number of half lives = T elapsed / Half lives
Number of half lives = 140 days / 35 days
Number of half lives = 4
Amount left:
At time zero = 610 g
At first half life = 610 g/2 = 305 g
At second half life = 305 g/2 = 152.5 g
At 3rd half life = 152.5 g/2 = 76.25 g
At 4th half life = 76.25 g /2 =38.125 g
Amount left after 140 days is 38.125 g.
how many neutrons are present in the isotope of nobelium, No-254?
575/2000 in ratio please send me photos of this answer
Answer:
23 : 80
Not sure
No time for pictures
Answer:
[tex]{\huge{\pink{\underline{\underline{SoLuTiOn}}}}}[/tex]
Refer to above attachment...
Ocean waves are limited in
Answer:
are there answer choices with the question?
Explanation:
sorry im a little confused
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.
What does an elements location tell us about the forces within an atom?
Answer:
Forces inside the atom
The atom is comprised of three major particles—protons, neutrons and electrons. There are four forces (Electromagnetic, Strong, Weak, and Gravity) that are responsible for the behavior of the particles and thus keep the atom together.
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 atomsWhat’s the answer????
Answer:
all of above
Explanation:
5.
If 6.5 g of magnesium ribbon reacts completely
with hydrochloric acid, how many grams of
hydrogen gas would be liberated? Mg , + 2HC1(ag)
→ MgC1 + H, [H = 1.0, Mg = 24.0]
Answer:
The mass of hydrogen gas liberated is 0.6 g.
Explanation:
Given data:
Mass of Mg = 6.5 g
Mass of hydrogen gas liberated = ?
Solution:
Chemical equation:
Mg + 2HCl → MgCl₂ + H₂
Now we will calculate the number of moles of Mg.
Number of moles = mass / molar mass
Number of moles = 6.5 g/ 24 g/mol
Number of moles = 0.3 mol
Now we will compare the moles of Mg with hydrogen gas.
Mg : H₂
1 : 1
0.3 : 0.3
Mass of H₂:
Mass = number of moles × molar mass
Mass = 0.3 mol × 2 g/mol
Mass = 0.6 g
Which two particles are found in the nucleus of an atom?
Answer:
Protons and neutrons
Answer:
Protons and Netrons
hope this helps
which elements have similar chemical properties
A) Na, K, Mg
B) B, Al, S
C) N, O, F
D) He, Ar, Kr
beeans beans beans beans beans!!
Answer:
points go brrrrrr
Explanation:
Answer:
Beans.
Explanation:
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:
Calculate the number of moles of neon gas in 8.15 atoms of neon gas
Answer:
13.5 moles Ne
Explanation:
Atoms --> Moles
1. Put the given number over 1
2. Multiply by 6.022x10^23 to get to moles
3. Round by sigfigs
(8.15x10^24 atom Ne(g)/1) (1 atom Ne(g)/6.022x10^23molesNe)=13.5337...
13.5337 --> 13.5 moles Ne
What is the KE at 1 m?
Answer:
K.E. = 1/2 m v2
Explanation:
What is the mass of 6.02 × 10²³ hydrogen atoms
Answer:
1.0 something depending on your periodic table.
Explanation:
You are given atoms. Not molecules. The mass is what you would read from the periodic table. 1.000 in some form is the answer.
In nature, Hydrogen is found as H2 everywhere except in the sun or a star. The molecular mass (not the atomic mass) would be 2.000 something.
PLS HELP ASAP
salt water is a pure substance
true or false?
Answer:
false
Explanation:
salt water cannot be classified as a substance because it's composition can vary
Susan made observations about outside events she noticed throughout the day. The day began with rain. Susan saw puddles on the road. The rain stopped and the sun began to shine. The puddles disappeared. Later, clouds began to form in the sky. How do the parts of the water cycle relate to the events that Susan saw?
Answer:
Rainfall - precipitation
disappeared puddles - evaporation
cloud formation - condensation
Explanation:
Rainfall that is observed by the Susan is the precipitation of the water cycle in which the water vapor that was condensed become heavy and form droplets of water and fall from sky to the earth surface.
Puddles that formed due to rainfall are the collection of water in the water cycle which is evaporated (process: evaporation) into the atmosphere n the form of water vapor which condensed to form clouds.
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:
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.
Also please rate 5 and give thanks.
What is the pH of a solution prepared by dissolving
0.8 g NaOH in water to make 200 mL solution?
Answer:
pH>7
Explanation:
bases tend to increase the pH of a solution. since water has the pH of 7 and NaOH has pHof 14, the overall pH of solution will increase.
hope it's helpful.
Answer:
[tex]{\huge{\pink{\underline{\underline{Question:}}}}}[/tex]
What is the pH of a solution prepared by dissolving
0.8 g NaOH in water to make 200 mL solution?
[tex]{\huge{\pink{\underline{\underline{Answer:}}}}}[/tex]
pH>7
Bases tend to increase the pH of a solution.Since,water has the pH of 7 and NaOH has pH of 14, the overall pH of solution will increase.
How do you tell which isotope is more abundant?
Answer: To determine the most abundant isotopic form of an element, compare given isotopes to the weighted average on the periodic table.
Which of the following is NOT a type of scientist?
A. Geologist
B. Botanist
C. Meteorologist
D. Cryptologist
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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Compounds are pure substances. What other substances are considered pure substances?
Answer:
um... hydrogen gas
gold metal
sugar (sucrose)
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).
The density of this material is 2 g/cm^3.There are 24 cm^3.
What is the total mass?
Answer:
[tex]\boxed {\tt 48 \ grams}[/tex]
Explanation:
Mass can be found by multiplying the density by the volume.
[tex]m=d*v[/tex]
The density is 2 grams per cubic centimeter.
The volume is 24 cubic centimeter.
[tex]d= 2 \ g/cm^3 \\v=24 \ cm^3[/tex]
Substitute the values into the formula.
[tex]m= 2 \ g/cm^3 *24 \ cm^3[/tex]
Multiply. Note that the cubic centimeters, or cm³ will cancel each other out.
[tex]m= 2 \ g * 24[/tex]
[tex]m= 48 \ g[/tex]
The mass of the material is 48 grams.
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:
2
1. Biology is the study of
Answer: biology is the study of life
Source:trust me bro
how to draw Bohr Model of Phosphorus??
Answer:
look at the image below
Explanation:
The Bohr model of phosphorus depicts 15 electrons in different energy levels, with the nucleus at the center.
Two electrons are present in the first energy level, eight electrons are present in the second and five electrons are present in the third. The electron configuration of phosphorus, which is [tex]1s^2 2s^2 2p^6 3s^2 3p^3[/tex], matches this distribution.
The formula [tex]2n^2[/tex], where n is the energy level number, determines the maximum number of electrons in each energy level. Therefore, the first energy level can accommodate only two electrons, the second energy level up to eight, and the third energy level up to eighteen.
Learn more about Bohr model, here:
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A rock can be broken down into different kinds of substances by physical processes. No chemical reactions are
needed to separate different parts of a rock into pure substances. This is because a rock is a
A. compound
B. element
C. mineral
D. mixture