Need help with #1 and #2

Need Help With #1 And #2

Answers

Answer 1

Answer:

To calculate half life, divide original value by 2.

1.

FOUR HALF LIVES = divide original value by 2, 4 times.

40÷ 2 = 20

20 ÷ 2 = 10

10 ÷ 2 = 5

5 ÷ 2 = 2.5g

2. AFTER TEN DAYS (TWO HALF LIVES)

140 ÷ 2 = 70

70÷ 2 = 35g

AFTER TWENTY DAYS (FOUR HALF LIVES)

140 ÷ 2 = 70

70 ÷ 2 = 35

35 ÷ 2 = 17.5

17.5 ÷ 2 = 8.75g


Related Questions

why do garden manure and compost fertilize the soil​

Answers

gardens arent real the government is lying the world is a simulation

As the soil absorbs manure, nutrients are released. This enriches the soil, which in turn helps the plants. The most important benefit of using manure in the garden is its ability to condition the soil For instance, mixing manure with sandy soils helps to retain moisture levels.

Mg + 2HCl ---> MgCl2 + H2
How many grams of MgCl2 would result from a reaction involving 24.31 g of Mg?​

Answers

assumed that all of the initial Mg had reacted, therefore the total amount of Mg had transferred into Mg2+ in MgCl2

Molar mass for Mg is 24.31 g/mole and MgCl2 is 95.21 g/mole

--> nMgCl2= nMg = 24.31 g ÷ 24.31 g/mole = 1 mole

--> so the mass of MgCl2 = 1 mole × 95.21 g/mole = 95.21 g

cho các chất sau NaO2,Na,NaOH,Na2SO4,Na2SO3,NaCl,AgCl hãy lập thành dãy chuyển hoá , hoàn thành bằng phương tình phản ứng

Answers

Answer:

brainless me plss i help you out

A mixture of neon and argon gases exerts a total pressure of 2.39 atm. The partial pressure of the neon alone is 1.84 atm, What is the partial pressure of the argon?

Answers

Answer:

0.55 atm

Explanation:

According to Dalton's law of partial pressures,

The total pressure is the summation of the partial pressures of individual gases in a sample of non-reactive gases.

Since Neon and Argon are noble gases, they do not react with each other. So we can apply Dalton's partial pressure law.

P total = P Ar + P Ne

2.39 atm = P Ar+ 1.84 atm

P Ar = 2.39 atm - 1.84 atm

       = 0.55 atm

According to the Dalton's law of partial  pressure the partial pressure of the argon is 0.55 atm.

What is pressure?

Pressure is defined as the force applied on an object perpendicular to it's surface per unit area over which it is distributed.Gauge pressure is a pressure which is related with the ambient pressure.

There are various units by which pressure is expressed most of which are derived units which are obtained from unit of force divided by unit of area . The SI unit of pressure is pascal .

It is a scalar quantity which is related to the vector area element with a normal force acting on it.It is distributed over solid boundaries and across arbitary sections of fluid normal to the boundaries at every point.

In this case, pressure of gas argon is obtained by subtracting pressure of gas neon  from the total pressure ,that is 2.39-1.84=0.55 atmosphere.

Thus ,the partial pressure of gas  argon in atmosphere is 0.55 atmosphere.

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What are the three zones in almost all human cells?
O cytoplasm, mitochondria, plasma membrane
O ribosomes, genetic material, cytoplasm
O nucleus, cytoplasm, plasma membrane
O mitochondria, genetic material, plasma membrane

Answers

C - nucleus, cytoplasm, plasma membrane.

Use the following image to answer the following questions. A student was performing an experiment using two identical cups made of styrofoam. The student had Cup A holding water at 90℃ and Cup B holding water at 20℃. The student then put an Aluminum Bar into each cup that was touching the water. As time passed, the student noticed that the temperature of the water in Cup A and Cup B began to change. Question:
A. Predict what will happen to the temperature of the water in Cup A and Cup B after 1 hour has passed.
B. Explain and give evidence for what type of heat transfer is occurring between the 2 cups.

Whoever answers my question gets brainliest

Answers

Answer:

The water will eventually become the same temature (A)

Which choice is an element?

A. Salad
B. Sugar
C. Water
D. Potassium

Answers

Answer: D. Potassium

Explanation:

A. Salad- a mixture of vegetables or fruits❌

B. Sugar- a compound made up of many elemnts❌

C. Water-  a molecule made up of two elements (water and hydrogen)❌

D. Potassium- the only pure element of the options provided.✅

Answer:

D, potassium

Explanation: took test ! btw

Occurs between a metal atom and a nonmetal atom.

Options:
Ionic Bond or Covalent Bond?

Answers

Ionic Bond is the correct answer

Sharon reads two different articles about avocados. The first article, in a weight-loss magazine, claims that avocados are unhealthy because they are high in fat. The second article, in an annual publication from a doctors’ group, claims that the fat in avocados is a type that is good for the heart.

To assess these claims, which question might Sharon ask?

Which source do avocados come from?
Where are avocados sold?
Is the source an authority on the subject?
How much do avocados cost?

Answers

Answer:

The correct anwser would be C

Explanation:

Answer:

The answer is C. Is the source an authority on the subject?

Explanation:

how is an inoculating loop or needle sterilized prior to use?

Answers

Answer:

it is placed over a bunsen burner to heat up and remove all bacteria

Explanation:

3. Write balanced ionic equations to show the dissolution of the following compounds in water: a) magnesium chloride​

Answers

Answer:

MgCl2 + H2O

Explanation:

what is the amount of heat required to completely melt a 200

Answers

A 200 what? Then I can help!

how does the advancement of medical technology increase the number of medical ethical issues that arise?

Answers

Answer:

People are getting richer and richer as technology advances, this may make it so that some people are getting treated unfairly. Signs of little money may support the reason that you are not getting the help you need; this means that health problems would arise more, resulting in an unfair lifestyle.

Someone pls help me I will make you brain

Answers

Answer:

lll and ll

Explanation:

Which of the following is a true statement?

Growth cycles only happen to reptiles.
Growth cycles happen to all animals.
Growth cycles only happen to birds.
Growth cycles only happen to mammals.

Answers

Answer:

its either all animals or only mammals. the thing with all animals is that they do have life cycles but not the same as like say humans or elephants, some are complicated.

Although almost 80% of the atmosphere is made up of nitrogen gas, most living things
don't have the enzymes necessary to use nitrogen directly from the atmosphere. How
we obtain the nitrogen we need to make proteins and DNA if we can't obtain it from
breathing?

Answers

Answer:

We don’t have the enzymes necessary to remove nitrogen from the atmosphere; we get our nitrogen from the food we eat. ^^

Although almost 80% of the atmosphere is made up of nitrogen gas, most living things don't have the enzymes necessary to use nitrogen directly from the atmosphere. We obtain the nitrogen we need to make proteins and DNA, if we can't obtain it from breathing we can get it by eating organic plants and animals.

Why is Nitrogen important for humans?

Nitrogen is a key element in the nucleic acids DNA and RNA, which are the most important of all biological molecules and crucial for all living things. DNA carries the genetic information, which means the instructions for how to make up a life form.

It is used to make amino acids in our body which in turn make proteins. The human body comprises 3% nitrogen (by mass). It is an essential part of amino acids (makeup proteins), nucleic acids (DNA, RNA), ATP (energy molecule), etc. It is nearly impossible to live without nitrogen.

Therefore, Although almost 80% of the atmosphere is made up of nitrogen gas, most living things don't have the enzymes necessary to use nitrogen directly from the atmosphere. We obtain the nitrogen we need to make proteins and DNA, if we can't obtain it from breathing we can get it by eating organic plants and animals.

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Helppppp I need it ASAP

Answers

Question 6
a) B
b) A

Question 7
a) Iron
b) oxygen, water
c) i) Galvanizing
ii) Painting

Help meeeeeeeeeeeeeee ​

Answers

this is the answer hope it helps you!!

If you have two pistons in a system, which exerts the larger force?

Answers

Answer:

The larger piston

Explanation:

(i just took the same test)

2. If Ben ran for 15 minutes and went 120 meters, how fast did he run?​

Answers

Answer:

8m/min

Explanation:

120 m / 15 min = 8 meters per min

8m/m
120 m / 15 m = 8

Find the number of protons, neutrons, and electrons for hydrogen-1, hydrogen-2, and hydrogen-3 respectively.

Answers

Answer:

Protons Neutron Electrons

hydrogen-1 1 0 1

hydrogen-2 1 1 1

hydrogen-3 1 2 1

Explanation:

hydrogen-1, hydrogen-2, and hydrogen-3 are all isotopes.

Isotopes have the same number of protons but a varying number of neutrons. Protons = Electrons.

If there are 100 black beans, 27 brown beans, and 173 white beans in the container, what is the percent composition of the container by bean

Answers

Answer:

300

Explanation:

Las legumbres son semillas de plantas grandes, carnosas y coloridas. Los frijoles, los guisantes (arvejas) y las lentejas son todos tipos de legumbres.

Which statement best describes a physical change?

1 Changes can occur to certain chemical properties of the substance, but the overall shape of the substance will remain the same.
2 Changes can occur to certain physical properties of the substance, but the overall shape of the substance will remain the same.
3 Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same.
4 Changes can occur to chemical properties of a substance, but the chemical composition of the substance remains the same.

Answers

Answer:  3 Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same

Explanation:

Physical change mainly physical properties of a substance while the chemical changes remain unchanged. Once there is a change to the chemistry of the substance, this would be classified as a chemical change.

The answer is 2 because the composition won’t change just the physical aspects

Which of the following is a liquid someone help!!!!!

Answers

Juice cause it’s the only thing that will go down ur throat like it’s a slip in slide

THE ANSWER IS ON THE PICTURE HOPE IT HELPS

What is climate? How does it differ from weather

Answers

Weather refers to short term atmospheric conditions while climate is the weather of a specific region averaged over a long period of time. Climate change refers to long-term changes.

for 2.02
Control group: cricket frog population Reminder: The test variable is the item that is changing in this investigation. The outcome variable is the item that you are measuring in this investigation. The control group is the group in the experiment where the factors being tested are not applied. It allows scientists to set a baseline to compare the experimental groups that do have factors applied to them.
Test variable (independent variable):
Outcome variable (dependent variable):

Answers

Limiting factor- Food, Pollution, Predators.

Outcome variable (dependent variable): Cricket Frog (population)

Control group: Cricket Frogs in the Florida Everglades without changes in or manipulation of the population.

Joshua loads a water balloon into a giant sling shot, pulls it back, and launches the balloon toward a target. The balloon misses the target by 3 feet, so he decides to try again. Which part of the process demonstrates an application of force?

Answers

When he pulls it back it applies force

answer please ASAP???? 50 pointtttsss
pls

Answers

Answer:

Whats the question

Explanation:

Answer:

Where is the question?

Explanation:

Anyways hru all? I've been pretty good

Draw the reaction of bromoethyne with 2 molecules of HBr. Name the product(s) and the type of reaction.
PLEASE HELP!!

Answers

this maybe can help you

i am sorry if not

Bromo-ethene is a product and it is a electrophilic addition reaction.

What is chemical equation?

A chemical equation is a method of representing a symbols and formulas of substance involved in this equation.

For example:  zinc metal reacts with dilute sulfuric acid to form zinc sulfate and hydrogen gas.

Types of chemical reactions:

combination reactions decomposition reaction precipitation reaction neutralization reaction

Electrophilic addition reaction

In this reaction containing a double or triple bond and this one hour breakdown into 2 π and 2 Sigma bonds.

In this reaction HBr undergoes heterolytic bond fusion the protons bonds with the carbon atom of the Carbon triple bond this result in the formation of carbo cation immediate the bromide iron forms a bond with the carbon cation producing Bromo-Ethene.

CH ≡ CBr + 2HBr  →  Br-CH=CH₂ (Bromo-ethene)

In these reaction Bromo-ethyne react with hydrogen bromide it form Bromo-ethene.

Bromo-ethene is a product and it is a electrophilic addition reaction.

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Which statement correctly compares ice and liquid water?
A. Both liquid water and ice have definite shapes.
B. Particles of liquid water have more energy than particles of ice.
C. Liquid water has a lower temperature than ice.
D. Ice has a definite volume, but liquid water does not.

Answers

Answer:

B. Particles of liquid water have more energy than particles of ice.

Explanation:

We can work this out through eliminating the wrong statements.

A. Both liquid water and ice have definite shapes.

This is wrong because, as stated in the question, water is a liquid, and one of the properties of liquids is that they change shape to fit the shape of their container. If it changes shape, it does not have a "definite" shape.

B. Particles of liquid water have more energy than particles of ice.

This is correct, and here is why. There are 3 states of matter: solid, liquid and gas. As you apply heat energy to an object at each state, the particles receive more energy and can move around more (this is kinetic energy). In the case of liquid (water) and solid (ice), particles in solids do not have much energy and stay in rigid formations. They do vibrate slightly, but only on the spot (this is what gives solids "definite" shapes). On the other hand, particles in liquids have more energy than particles in solids, which means that they can move more (more kinetic ENERGY) and do not stay in formations (this is why they do not have "definite" shapes). Therefore, particles in liquids (water) have more energy than particles in solids (ice), and this statement is correct.

C. Liquid water has a lower temperature than ice.

This is wrong because liquids have more energy than solids. As explained earlier, the reason why particles in liquids have more energy is because more HEAT energy has been applied to them. In the same way, solids have less energy because less HEAT energy has been applied to them. Less heat means a lower temperature. (Also you can use common sense for this one, ice feels colder than liquid water, right?)

D. Ice has a definite volume, but liquid water does not.

This is wrong because of the law of conservation of mass. This law states that particles (or matter or volume) cannot be created or destroyed. When ice melts and becomes liquid water, it has not lost volume: the particles have just gained more energy. This question is most likely there to confuse you, because all substances have definite volumes.

I hope this helps!

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