The half-life of lead-212 is 11h. How much of a 100-g sample of lead-212 is left after 33h?


Someone please help

Answers

Answer 1
After 33 hours, the sample would have undergone a halving 3 times, as its half life is 11 hours.

This would mean that after 33h, only 12.5grams of Lead-212 are left over.

Related Questions

A balloon is a sphere with a radius of 5.0 m. The force of air against the walls of the balloon is 45 N. What is the air pressure inside the balloon? Surface area = 12.56 × radius² 1 Pa = 1 N/m² How would I solve this problem? What are the steps or a good way to remeber how to solve?

Answers

Answer:

0.127 N/m² or 0.127 Pa

Explanation:

From the question given above, the following data were obtained:

Radius (r) = 5 m

Force (F) = 40 N

Pressure (P) =.?

Next, we shall determine the Surface area of the sphere (i.e the balloon). This can be obtained as follow:

Surface area = 12.56 × r²

Radius (r) = 5 m

Surface area = 12.56 × 5²

Surface area = 12.56 × 25

Surface area = 314 m²

Finally, we shall determine the pressure as follow:

Force (F) = 40 N

Surface area = 314 m²

Pressure (P) =.?

Pressure = Force /Area

Pressure = 40/314

Pressure = 0.127 N/m² = 0.127 Pa

Therefore, the pressure inside the balloon is 0.127 N/m² or 0.127 Pa.

Which indicates that thermal energy is no longer being transferred from boiling water to a mug?

The mug and the water lose all thermal energy.
The water is hotter than the mug.
The mug is hotter than the water.
The water and the mug are the same temperature.

Answers

Answer:

Which indicates that thermal energy is no longer being transferred from boiling water to a mug?

The mug and the water lose all thermal energy.

The water is hotter than the mug.

The mug is hotter than the water.

•The water and the mug are the same temperature.

Explanation:

answer #D is correct

When the water and the mug are at the same temperature then thermal energy will no longer be transferred from the boiling water to the mug. Therefore, option (D) is correct.

What is thermal energy?

Thermal energy is generated in a substance when an increase in temperature causes atoms and molecules to move at a faster speed and result in the molecules colliding with each other. The energy generated from the temperature of the heated material is called thermal energy.

Thermal Energy or internal kinetic energy is because of the random motion of molecules in the system. The thermal energy of any system is directly proportional to its temperature.

The more the temperature of the system, the more the movement of molecules within a given system, and the more the thermal energy of the system.

The thermal energy will be transferred from the boiling water to the mug when the water is hotter than the mug. When both have the same temperature then the thermal energy is no longer being transferred from boiling water to a mug.

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Explain Newton's first law of motion. Write your answer in the essay box below.

Answers

Answer:

I hope this helps :D

Explanation:

Newton's first law expresses that each object  will stay very still or in uniform movement in an orderly fashion except if constrained to change its state by the activity of an outside power. ... The third law expresses that for each activity (power) in nature there is an equivalent and inverse response.

Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia. ... If that velocity is zero, then the object remains at rest.

Match the element with their place on the periodic table.

Question 4 options:

Period 4, group 5-

Period 5, group 7-

Period 7, group 5-

Period 5, group 4-

1. dubrium

2. technetium

3. zirconium

4. vanadium

Answers

Answer:

Period 4, group 5- Vanadium

Period 5, group 7- Technetium

Period 7, group 5- Dubnium

Period 5, group 4- Zirconium

Explanation:

Steps for Seperating mixtures flowers peteale water and sugar

Answers

Answer:

How can we separate sugar from the mixture of sugar and water like we can remove acetone from water? The mixture of sugar-salt solution can be separated by evaporation. If the water is completely evaporated we will get separated sugar from the mixture.


The density of air at STP is 1.285 g/L. Which of the following cannot be used to fill a balloon that will float in air at STP?

Answers

NO can't  be used to fill a balloon

Further explanation

Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.

Answer options that need to be added :

a. Ne

b. NO

c. NH₃

d. CH₄

e. HF

will float in air ⇒ element or compound to fill the balloon, its density must be less than < 1.285 g/L

We can use the ideal gas formula ta find density :

[tex]\tt \rho=\dfrac{P.MW}{RT}[/tex]

Because at STP, then the constant value is

[tex]\tt \rho=\dfrac{1~atm\times MW}{0.08205\times 273.15~K}\\\\\rho=0.0446\times MW[/tex]

So that the density is determined from the MW(molecular weight) of each element or compound

a. Ne

Ar = 20.1797 g/mol

[tex]\tt \rho=0.0446\times 20.1797=0.9~g/L[/tex]

b. NO

MW=30.006 g/mol

[tex]\tt \rho=0.0446\times 30.006=\boxed{\bold{1.338~g/L}}[/tex]

c. NH₃

MW=17.0306 g/mol

[tex]\tt \rho=0.0446\times 17.0306=0.760~g/L[/tex]

d. CH₄

MW=16.04 g/mol

[tex]\tt \rho=0.0446\times 16.04=0.715~g/L[/tex]

e. HF

MW=20.01 g/mol

[tex]\tt \rho=0.0446\times 20.01=0.892~g/L[/tex]

Radon-222 is an alpha emitter with a half life of 3.82 days.

1. What is the mass number of the daughter isotope?
2. What is the element symbol of the daughter isotope?
3. What is the atomic number of the daughter isotope?​

Answers

The daughter isotope (a decay product): Polonium (Po)

Further explanation

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

alpha α particles ₂He⁴ beta β ₋₁e⁰ particles gamma particles γ positron particles ₁e⁰

Radon-222 emits alpha α particles ₂He⁴  , so the atomic number decreases by 2, mass number decreases by 4

Reaction

[tex]\tt _{86}^{222}Rn\Rightarrow _{84}^{218}+_2^4He[/tex]

1. The mass number of the daughter isotope = 218

2 and 3. If we look at the periodic system, the element with atomic number 84 is Polonium (Po)

what chemical is C2H4O2

Answers

Answer:

C2H4O2 is Acetic acid.  

Explanation:

Acetic acid is a colourless liquid organic compound with the chemical formula CH3COOH (also written as CH3CO2H or C2H4O2). It is in the department of a chemical compound known as Glycolaldehyde. It is the smallest possible molecule that contains both an aldehyde group and a hydroxyl group.

Based on the Phase Change Graph below, what is the Melting Point for this point
substance?

Answers

Answer:

Where is the phase melting graph? Can't seem to find it

A student decided to research primate psychology for their science project. They measured how long it took gorillas to adapt to their new habitat when moved from one zoo to another. They measured how long it took the new gorilla to interact regularly (more than 3 times per day) with the gorillas that already live there. Seven different cases were examined and the data collected. What can be said about the data? [GorillaTime to interact (days)12.523.138.343.352.763.273.4]
[
Gorilla 1 2 3 4 5 6 7 Time to interact (days) 2.5 3.1 8.3 3.3 2.7 3.2 3.4
]
A. The data is only measured to one decimal place, so it is not reliable.
B. The data falls within similar ranges so it may be reliable.
C. The data is reliable because there is only one outlier.
D. The data may not be reliable because there is an outlier.

Answers

Answer: the answer is  D im pretty sure

Explanation:

The formula for finding density of a regularly shaped object is LxWxH.
True
False

Answers

                                Its true im pretty sure

It's true

Hope this helped!

Which scientist did people think was insane so they dismissed his ideas for almost 2000 years?

Answers

Alfred Wegener


I think let me know if I am wrong

is CO2 a compound, molecule, or atoms/elements?

Answers

Answer:

CO2 is a compound cause there is more then one

I need help with the 2nd part first gets brainlist

Answers

Answer:

7. 4H₂O

Elements: Hydrogen, Oxygen

Number of molecules: 4

Number of elements: 8 H, 4 O

Number of Atoms: 12

Explanation:

The elements are determined by the their symbol i.e. H = hydrogen.

The number of molecules is determined by the coefficient ( the number in front of everything, in this case 4).

The number of elements is determined by the coefficient and the subscripts. Multiply the coefficient by the subscript after each element. When there is no subscript, it is equal to 1.  4H₂ = 4x2 = 8;  4O = 4x1 = 4.

The number of atoms is all the individual elements added together. 8+4 = 12.

What is the volume of kristas rock

Answers

Answer:

30

Explanation:

Measure the water rised in the beaker which is 180 and subtract 150 and you get 30

Iron is a
homogenous mixture
O heterogeneous mixture
O element
compound

Answers

Answer:

element

Explanation:

Which of the following is a practice that shows you have intellectual honesty?
A. letting your beliefs influence your results
B. avoiding plagiarism of the works of others
C. making up data to support a special cause
D. copying the work of other scientists and claiming it as your own

Answers

Answer:

Avoid plagiarism and the work of others

Explanation:

I took the test and got it right. Hope this helps :)

Avoiding plagiarism of the work of others shows that you have intellectual honesty. So the correct option is B.

What is plagiarism?

The act of presenting someone else's ideas or work as your own, with or without that person's agreement, by integrating it into your work without giving it due credit, is known as plagiarism. This definition applies to all works, both published and unpublished, whether they are in manuscript, print, or electronic form.

Plagiarism can be willful, careless, or accidental. Plagiarism that is deliberate or careless is prohibited under exam regulations and is grounds for disciplinary action. In addition to text, additional media such as computer code, pictures, graphs, etc. must also include credit for the ideas and works of others.

It equally applies to both published and unpublished text and data taken from books and journals, lectures, theses, and other students' writings. Text, information, or other materials that you take from websites must also be credited.

Learning and using the rules of good academic practice from the start of your university career is the best way to prevent plagiarism.

Therefore the correct option is B.

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The missing components in the table to the right
are indicated with orange letters. Complete the
table by filling in the corresponding number(s) or
symbol(s) below.
A
B
1111
С
D
E
F
G

Answers

Further explanation

The Atomic Number (Z) indicates the number of protons in an atom of an element. If the atom is neutral then the number of protons will be equal to the number of electrons. So the atomic number can also indicate the number of electrons.

Mass Number (A) = Number of protons + Number of Neutrons

Atomic Number (Z) = Mass Number (A) - Number of Neutrons

Atomic number = number of protons = number of electrons  ⇒ neutral atoms

Atomic number - positive charge = number of electrons ⇒ cation

Atomic number + negative charge = number of electrons ⇒ anion

You can also see the periodic system

A. Indium (In)

B. proton = electron = 27

C. proton = electron = 73

D. proton = electron = 49

E=F. atomic mass - neutron = 137 - 81 = 56

G. atomic mass-proton = 115- 49 = 66

H. 181-73 = 108

Answer:

I know I´m kinda late but....

Explanation:

A. In

B. 27

C. 73

D. 49

E. 56

F. 54

G. 66

H. 108

I. 32

4. Know the location of metals, non-metals and metalloids

Answers

Answer:

The metals are to the left of the line (except for hydrogen, which is a nonmetal), the nonmetals are to the right of the line, and the elements immediately adjacent to the line are the metalloids.

Hope this helped

I WILL GIVE U BRAINLIST

Read this passage from "The Secret Life of Walter Mitty."

"Puppy biscuit," said Walter Mitty. He stopped walking and the buildings of Waterbury rose up out of the misty courtroom and surrounded him again.

A woman who was passing laughed. "He said ‘Puppy biscuit,’" she said to her companion. "That man said ‘Puppy biscuit’ to himself."


What does the dialogue in the excerpt show about Mitty?

He is awkward and absentminded.

He is responsible and conscientious.

He is funny and entertaining.

He is sour and nasty.

Answers

Answer:

He is awkward and absentminded.

Explanation:

"The Secret Life of Walter Mitty" by James Thurber presets the story of Walter with a dream. The beginning of the story reflects on the idea that the story is more inclined towards the dreams and fantasy-full world rater than reality. Walter's dreams are a mixture of reality and his imagination. He spoke certain words those do not have meaning in reality. He calls himself 'Puppy Biscuit" to which the women reacted with a laugh. This represented his absent-minded character and his appeal towards is dreams.

3. Which of the following is used to calculate the average atomic mass of an element?

Answers

I believe the answer is B the total number of naturally occurring isotopes. :)

What are alkali metals

Answers

Answer:

Alkali metals are highly reactive elements that appear to be silver and they are found in group 1 of the periodic table.  It consists of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).  As you go further down the group, the more reactive they are.  Those elements all react to water and air, so they must be kept in oil to preserve their state.  

Alkali metals are any of the elements lithium, sodium, potassium, rubidium, cuisine, and francium, occupying Group 1A (1) of the periodic table. They are very reactive, electropositive, monovalent metals forming strongly alkaline hydroxides.

explain the effect of temperature, pressure, volume and concentration reaction rate

Answers

When you increase the pressure, the molecules have less space in which they can move. That greater density of molecules increases the number of collisions. When you decrease the pressure, molecules don't hit each other as often and the rate of reaction decreases. Pressure is also related to concentration and volume.

PLEASE MARK ME AS BRAINLIEST

On the periodic table, the period number can identify the number of energy levels an element will contain.


False

True


i need help

Answers

Answer: True.
Hope this helps!!

Choose each statement that is scientific.
a. The universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago.
b.The opinions of randomly selected participants in a survey prove the idea that global temperatures are not increasing on Earth.
c.Ocean tides are caused by the uneven gravitational pulls of the Moon and Sun on different parts of Earth.
d.Human life is more valuable than other forms of life on Earth because humans are more intelligent than other organisms.

Answers

Answer:

he universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago.

Ocean tides are caused by the uneven gravitational pulls of the Moon and Sun on different parts of Earth.

Explanation:

These statements are objective truths or rational speculations adequately supported by evidence.  The others are from unreliable sources, and are based on opinion.

the answer is A!

Answer:

A and C are correct, I took the test

Explanation:

which of the following is not a name given for the four outer plantets

1. gas Giants
2. Jovian planets
3. Terrestrial planets

Answers

Hey :)

The answer is 3. Terrestrial planets

Gas giants and Jovian planets are names for the four outermost planets

Terrestrial planets are the names for the four innermost planets
They are called terrestrial because they have a compact, rocky surface

Hope this helps!

The one that is not a name given for the four outer planets terrestrial planets. The correct option is 3.

What are Terrestrial planets?

The planets Mercury, Venus, Earth, and Mars are referred to as terrestrial because their surfaces are compact and rocky, similar to Earth's terra firma. The terrestrial planets are the solar system's four innermost planets.

A terrestrial planet, telluric planet, or rocky planet is one that is primarily composed of silicate rocks or metals.

Mercury, Venus, Earth, and Mars are the inner planets in the Solar System that are closest to the Sun and are classified as terrestrial planets by the International Astronomical Union.

Astronomers who use the geophysical definition of a planet may consider two or three planetary-mass satellites, including the Earth's Moon, Io, and occasionally Europa, as terrestrial planets, along with the rocky protoplanet-asteroids Pallas and Vesta.

Thus, the correct option is 3.

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what is a covalent bond? Apex

Answers

Answer:

Here is the meaning of covalent bond: covalent bond: a chemical bond in which two atoms share some of their valence electrons which creates a force that holds the atoms together

Hope this helps

Sky

A chemical bond in which two atoms share some of their valence electrons creates a force that holds the atoms together.

What is a covalent bond?

A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.

Covalent bonds have high bond dissociation energy as compared to the ionic bond. The overlapping of molecular orbital is bigger in the case of the covalent bonds as compared with ionic bonds.

Hence, covalent bonds are difficult to break and stronger than ionic bonds.

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Which element would be the least similar to magnesium (Mg)?

A) Na
B) Sr
C) Be
D) Ca

Answers

Answer:

NA

Explanation:

the other three options are alkali earth metals like magnesium (they are all in group 2). Sodium is the only one that is not an alkali earth metal.

The [tex]Na[/tex] element would be the least similar to magnesium ([tex]Mg[/tex] ).

Because all elements belongs to same group as magnesium except sodium.

Why elements belong to same group are similar?The vertical row in the periodic table is called group.The elements in the same group shows similar properties because the number of valence electrons is same for elements in same group.

What is valence electron?

The electron/electrons present in valence shell is called valence electrons.

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How many carbon atoms are there in 2.23 grams of propane (C3H8)?​

Answers

Answer:

3.05x10²³ (3 sig. fig.)

Explanation:

Propane (C₃H₈) is a colorless alkane gas with three carbons and eight hydrogen atoms. In 2.23 grams of propane, there are 3.05 x 10²³ carbon atoms present.

What is the number of particles/atoms?

The number of atoms or the particles being the smallest units is estimated by the product of the number of moles and Avogadro's number.

The Avogadro's number (Na) is used to determine the number of particles that have been present in a mole of a substance. A mole of a substance is said to have 6.022 × 10²³ ions, atoms, electrons, molecules, etc.

Moles of propane are calculated as,

Moles = mass ÷ molar mass

= 2.23 ÷ 440.094

= 0.05057

Now, the number of particles is calculated as,

Number = moles × Avogadro's number

= 0.05057 × 6.022 × 10²³

= 3.05 x 10²³

Therefore, 3.05 x 10²³ carbon atoms are present in 2.23 grams of propane.

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The density of cadmium is 8.65 g/mL, what is the volume of a 33.4 g object made of pure cadmium?

Answers

Answer:

Volume = 3.86 ml (Approx)

Explanation:

Given:

Density of cadmium = 8.65 g/ml

Mass of pure object = 33.4 g

Find:

Volume pure cadmium

Computation:

Volume = Mass / Density

Volume = 33.4 / 8.65

Volume = 3.86 ml (Approx)

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