Answer:
25 atoms
Explanation:
Given data:
Total number of atoms = 400 atom
Atoms remain after 4 half lives passed = ?
Solution:
At time zero = 400 atom
At first half life = 400 atom/2 = 200 atom
At 2nd half life = 200 atom/2 = 100 atom
At 3rd half life = 100 atom/2 = 50 atom
At 4th half life = 50 atom/2 = 25 atom
Thus, 25 atoms are remained after 4 half lives.
25 atoms of the radioactive atoms will remain after 4 half lives.
Given in the question,
Initial amount of a radioactive element = 400 atomsNumber of half lives = 4Expression for the amount remaining of a radioactive element after 'n' half lives is given by,
[tex]N=N_0(\frac{1}{2})^n[/tex]
Here, [tex]N_0=[/tex] Initial amount
[tex]n=[/tex] Number of half lives
By substituting the vales of [tex]N_0[/tex] and [tex]n[/tex] in the question,
[tex]N=400(\frac{1}{2})^4[/tex]
[tex]=\frac{400}{16}[/tex]
[tex]=25[/tex]
Therefore, 25 atoms of the radioactive atoms will remain after 4 half lives.
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True or false
Equal forces acting on one object in opposite directions are called balanced forces
Answer:
True
Explanation:
Forces, equal in magnitude and opposite in direction, and cancel each other out are called Balanced Forces.
Balanced Forces DO NOT cause any change in the velocity of the object, but the Object may correspond to a change in shape or size.
Example :
Blasting a balloon by compressing it tightly with both hands, roughly with an equal force, is a practical example of Balanced Forces. In this case, the balloon before the burst stays at a state of rest and same after the burst. But the burst or the compression, causes a change in the shape of the balloon.
Whar is the innermost par of the bone called
Answer:
If it's what I think you're talking about, it's called marrow.
Explanation:
Hope this helped! :)
Someone please help will mark as brainliest
Answer:
PET works by using a scanning device (a machine with a large hole at its center) to detect photons (subatomic particles) emitted by a radionuclide in the organ or tissue being examined.
Newer technology combines PET and CT into one scanner, known as PET/CT. PET/CT shows particular promise in the diagnosis and treatment of lung cancer, evaluating epilepsy, Alzheimer's disease and coronary artery disease.
Explanation: Most Brainliest Please
Hobbies options what is a better particle most similar to
Electron
The positive laser
Nucleus
Gamma ray
Answer:
Gamma ray
Hope this helps!!!!!!!!
Scientists claim that climate change is happening because Earth is warming. They also claim that humans have helped cause the warming by adding greenhouse gases to the atmosphere. Other people claim that Earth is not experiencing climate change because some winter days are still very cold. Use evidence to evaluate each claim about climate change.
Credit: https://climate.nasa.gov/causes/
The industrial activities that our modern civilization depends upon have raised atmospheric carbon dioxide levels from 280 parts per million to about 417 parts per million in the last 151 years. The panel also concluded there's a better than 95 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in Earth's temperatures over the past 50-plus years.
The panel's full Summary for Policymakers report is online at https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_summary-for-policymakers.pdf.
a + c = r solve for a
Answer: A = -c + r
Explanation:
Answer:
a = r-c. its that simple I guess
what happen when the nitrate of an alkali metal is heatad?
answer
Gives brown colour gas
A boundary between air masses that don't move possibly causing rain for several days.
Answer:
A Front
Explanation:
A Front is a boundary between two air masses of different density, moisture, or temperature
If a metal donates or loses an electron it becomes a..
A. Ionic
B. Covalent
C. Metallic
Answer:
c
Explanation:
Answer:
the answer to your question is c
Develop a relationship (in the form of a single sentence or equation) that can predict the charge based on the number and types of particle.
Answer:
The charge of an atom is determined by the ratio of protons to electrons
Explanation:
I hope this helps!!
A relationship showing the charge on an atom can be expressed as ;
Types of particle are protons and electrons Charge on atom = ( Number of protons - Number of electrons )The charge an atom posses depends on the particles/components of the atom which are protons and electrons. The protons are positively charged ions that are present in the nucleus of an atom while electrons are negatively charge ions present in the outer shell of an atom.
To predict the charge on an atom we will determine the difference between the number of protons and the number of electrons present in an atom.
Hence we can conclude that the relationship can be expressed as Types of particle are protons and electrons , Charge on atom = ( Number of protons - Number of electrons )
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true or false, water boils at 100°c
Answer:
This is true
Explanation:
name the ionic compound NH4NO3
Consider the following reaction: 3Fe(s) + 4H₂O(g) ➞ Fe₃O₄(s) + 4H₂(g). To answer the following question: "How many moles of hot water vapor (steam) must react to produce 275 g of Fe₃O₄?" How many steps will it take to get the answer? *
4 points
1
2
3
4
Answer: 2
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Fe_3O_4=\frac{275g}{233.5g/mol}=1.18moles[/tex]
[tex]3Fe(s)+4H_2O(g)\rightarrow Fe_3O_4(s)+4H_2(g)[/tex]
According to stoichiometry :
1 mole of [tex]Fe_3O_4[/tex] are produced by = 4 moles of [tex]H_2O[/tex]
Thus 1.18 moles of [tex]Fe_3O_4[/tex] will be produced by=[tex]\frac{4}{1}\times 1.18=4.72moles[/tex] of [tex]H_2O[/tex]
Mass of [tex]H_2O=moles\times {\text {Molar mass}}=4.72moles\times 18g/mol=85.0g[/tex]
Thus 85.0 g of [tex]H_2O[/tex] will be required and 2 steps are required to get the answer.
Yule logs are commercially available that burn with a red and green flame. What two chemicals could produce this effect?
Answer:
Strontium chloride: Makes a red flame.
Strontium sulfate: Makes a green flame.
Copper salts (such as copper sulfate or copper chloride) and barium salts (such as barium chloride or barium nitrate) can produce a red and green flame when burned.
The colors of flames are often determined by the presence of specific chemicals or elements that emit characteristic wavelengths of light when heated. In the case of red and green flames, copper and barium salts are commonly used.
Copper salts, particularly copper sulfate or copper chloride, can produce a green flame when burned. This is due to the emission of specific wavelengths of green light by excited copper ions in the flame.
Barium salts, such as barium chloride or barium nitrate, can produce a red flame when burned. The red color is caused by the emission of specific wavelengths of red light by excited barium ions in the flame.
When these two chemicals are combined in a yule log or firework formulation, they can create a visually appealing display of red and green flames. The copper and barium ions are heated and excited by the flame, releasing their characteristic colors of light. It is important to note that the production of colored flames should be done with caution and adherence to safety guidelines to ensure proper handling and disposal of chemicals.
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20 POINTS!!
Kinetic and Potential Energy
Answer:
When a ball is rolled up a hill, it has potential energy that can turned into kinetic energy. The kinetic energy would be the ball rolling down the hill.
Explanation:
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PLEASE I NEED THIS ANSWER ASAP :(
Impurities that evaporate easily and travel with the water vapor are not removed when using this type of distillation. Explain the reason for this.
Answer:
Please add as brainlist
Explanation:
Distillation is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation. Distillation may result in essentially complete separation (nearly pure components), or it may be a partial separation that increases the concentration of selected components in the mixture. In either case, the process exploits differences in the relative volatility of the mixture's components. In industrial applications, distillation is a unit operation of practically universal importance, but it is a physical separation process, not a chemical reaction.
Which factor can cause acceleration to decrease?
Many ladybird beetles live in Pedro's garden. He observed them one summer for a science project. Pedro noticed that all the ladybird beetles had red shells. Some of the beetles had many dark spots, some had only a few dark spots, and one or two beetles had no dark spots at all. Around the same time, Pedro's father replanted the garden using just red flowers. A few years later, Pedro observed the ladybird beetles again. This time he noticed that almost all the ladybird beetles had shells with more red visible. They had few or no dark spots on their shells. Pedro concluded that replanting the garden with red flowers caused a change in the ladybird beetle population. Which best explains Pedro's observations?
Answer:
No.
Explanation:
No, Pedro's observations does not suggest that replanting the garden with red flowers caused a change in the ladybird beetle population because the colour of flower has no effect on the change in the population of ladybird beetle, it must be occur due to the dominant genes present in the population of ladybird beetle. This dominant genes is responsible for the presence of more red colour on the ladybird beetles shells.
Someone please Help please When you are measuring your pulse (heart beats per minute) what system are you monitoring?
A. Digestive
B. Respiratory
C. Circulatory
D. Integumentary (skin)
Which is a component of John Dalton’s atomic theory?
The ratio of atoms in a compound is fixed.
The atoms of different elements are the same.
An atom is a small particle of matter that can be broken down.
A reaction can create or destroy atoms as well as rearrange them.
Answer: lol the answer is A
Explanation:
i’m just smart like that , thought i should give y’all a clue
Answer:
The ratio of atoms in a compound is fixed.
Explanation:
its a
By examining the diagram, which of the following is NOT needed for photosynthesis:
O sunlight
O carbon dioxide
O water
oxygen
How many atoms of each element are in the chemical formula Ca(OH)2?
Using the Assignment: Locating the Epicenter, What was the length of the radius of the circle of from the Buenos Aires station? (in cm)
Question 1 options:
3.2 cm
4.8 cm
5.76 cm
8 cm
After food is consumed, chemical nutrients are absorbed into the blood. The blood then carries these nutrients to the body's cells where the nutrients enter mitochondria. Which reaction must occur next for the cell to carry on other activities?
Answer:C
Explanation:oxygen,light,and glucose combine to produce high energy molecules
Answer:
c
Explanation:
I got this answer right so trust me
2H20--12H2 + O2
How many moles of H2 are produced when 2.54 moles of H2O reacted?
Answer:
2.54mole of H₂
Explanation:
The reaction expression is given as:
2H₂O → 2H₂ + O₂
Given;
Number of moles of H₂O = 2.54moles
Unknown:
Number of moles of H₂ produced = ?
Solution:
To solve this problem, we use the concept of mole comparison. Now from the reaction expression, we know that;
2 mole of H₂O will produce 2 mole of H₂
2.54 mole of H₂O will then produce 2.54mole of H₂
Write the name for the compound Al₂S₃
Answer:
Uh Joe stinky?
Explanation:
Answer:
Aluminum(2)sulfur(3)
Explanation:
Balance the following equations:
i. N2 + …..H2 → ….. NH3
ii. P4 + …….O2 → ….P2O5
iii. ……NaF + Br2 →…….NaBr + F2
iv. …..ZnS + …..O2 → …..ZnO + …..SO2
v. Pb(NO3)2 + …..NaCl → ……NaNO3 + PbCl2
(I) [tex]N_{2} + 3H_{2} --> 2NH_{3}[/tex]
(II) [tex]P_{4} + 5O_{2} --> 2P_{2} O_{5}[/tex]
(III) [tex]2NaF + Br_{2} -->2NaBr + F_{2}[/tex]
(IV) [tex]2ZnS + 3O_{2} --> 2ZnO + 2SO_2[/tex]
(V) [tex]Pb(NO_3)_2 + 2NaCl --> 2NaNO_3 + PbCl_2[/tex]
_____________________________________Best Regards,'Borz'Think about your morning from when you wake up until you arrive at school. Describe the forms of energy you encounter or use during that time. (Use types of energy like electrical, mechanical, thermal, etc)
Answer:
When sleeping the energy exhibited is Potential energy. When I wake up and I’m preparing for the day I use kinetic energy which is the energy exhibited during motion.
Eating before leaving the house means I used chemical energy for replenishment of nutrients to aid the performance of more activities for the day. The food eaten and the physical activities also give rise to thermal energy which is why we sweat.
cholrine is an active non-metal.why?