A rock originally has 2200 atoms of 235U and no 207Pb. It now has 800 atoms of 235U. Assuming the only chemical process is the radioactive decay of uranium to lead, what is the age of the rock

Answers

Answer 1

Answer:

[tex]Age=1040.55 million\ years[/tex]

Explanation:

From the question we are told that:

Initial Rock atoms [tex]a_1=2200atoms of 235^U[/tex]

Final Rock atom [tex]a_2=800 of  235^U[/tex]

Age of half life 713 million years

Generally the equation for Age is mathematically given by

[tex]\frac{1}{2^n}=\frac{800}{2200}[/tex]

[tex]\frac{1}{2^n}=\frac{1}{2.750}[/tex]

[tex]n=1.46[/tex]

Therefore

[tex]Age=713*1.46[/tex]

[tex]Age=1040.55 million\ years[/tex]


Related Questions

The freezing point of a substance is -20°C. Its boiling point is 120°C.
a. At 80°C the substance is in the state
b. At -50°C the substance is in the state.
C. At 140°C the substance is in the state.

Answers

Answer:

a. liquid

b. solid

c. gas, (should be at it's boiling point)

Explanation: If the normal melting point of a substance is below room temperature, the substance is a liquid at room temperature. Benzene melts at 6°C and boils at 80°C; it is a liquid at room temperature. If both the normal melting point and the normal boiling point are above room temperature, the substance is a solid.

if you need an explanation to each lmk

……….is strong due to the ……………..between positive ions and negative delocalized electrons

Answers

Answer:

atom &bond

Explanation:

atom is strong due to the bond

What is the concentration of Htions at a pH = 11?
mol/L
What is the concentration of Htions at a pH = 6?
mol/L
How many fewer Htions are there in a solution at a
pH = 11 than in a solution at a pH = 6?

Answers

Answer:
a) 1 x 10^-11 mol/L
b) 1 x 10^-6 mol/L
c) 1 x 10^-5 fewer H+ ions

Explanation

pH stands for Power of Hydrogen, the more acidic a substance is, the more H+ ions it has rendering the substance acidic. a pH of 1 means the concentration of H+ ions is 1 x 10^-1. A pH of 7 means the concentration of H+ ions is 1 x 10^-7 and so on.

10^-11 has 10^-5 more H+ ions than 10^-6

Hope this helps :)

(GIVING BRAINIEST!)
Which of the following compares the rainforest and the tundra environments correctly?

A. A rainforest is hotter than the tundra because it is closer to the equator.
B. A rainforest is less humid than the tundra because of its higher elevation.
C. A tundra has higher temperatures than the rainforest because it receives more
sunshine.
D. A tundra has higher humidity than the rainforest because of its proximity to water bodies.
For Science BTW!

Answers

Answer:

A

Explanation:

A rain forest is hotter than the tundra because it is closer to the equator

The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum.

a. True
b. False

Answers

Answer:

a. True

Explanation:

The main information that gives an infrared absorption spectrum is the type of functional groups that are present in an organic compound. The infrared (IR) spectroscopy is based on the fact that functional groups absorb light in the IR region of the electromagnetic spectrum (approximately at 2,500-16,000 nm) and induces a vibrational excitation of the covalently bonded atoms in the group. The vibration of the atoms can be of different types, such as stretching, bending, etc. Each functional group (such as the carbonyl group) in an organic compound absorbs at a specific IR frequency so they can be distinguished from an IR spectrum.

Which of the following best describes physical science?
0...
OA.
the study of motion
OB.
the study of matter and energy
O C.
the study of Earth's structure and processes
OD.
the study of reactions
O E.
the study of living things
Reset
Ne

Answers

B. The study of matter and energy.

Because physical science is everything that doesn't include organic things.

The  study of matter and energy among the following  best describes physical science.

What is matter?

Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it possess volume .Matter is composed up of atoms which may or not be of same type.

Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states  of substances such as solids, liquids and gases depending on the conditions of  the temperature and  the pressure.

The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.Matter is always conserved by law of conservation of matter.The law was proposed by Antoine Lavoisier.

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Using the following equation for the combustion of octane calculate the heat associated with the formation of 100.0 g of carbon dioxide. The molar mass of octane is 114.33 g/mole.

2C8H18 + 25O2 → 16 CO2 + 18 H2O

ΔH°rxn = -11018 kJ

Answers

Answer:

The right solution is "-602.69 KJ heat".

Explanation:

According to the question,

The 100.0 g of carbon dioxide:

= [tex]\frac{100.0 \ g}{114.33\ g/mole}[/tex]

= [tex]0.8747 \ moles[/tex]

We know that 16 moles of [tex]CO_2[/tex] formation associates with -11018 kJ of heat, then

0.8747 moles [tex]CO_2[/tex] formation associates with,

= [tex]-\frac{0.8747}{16}\times 11018 \ KJ \ of \ heat[/tex]

= [tex]-0.0547\times 11018[/tex]

= [tex]-602.69 \ KJ \ heat[/tex]

GIVING BRAINLIEST
Which equations are used to calculate the velocity of a wave?
O velocity = distance ~ time
velocity = wavelength x frequency
velocity = distance/time
velocity = wavelength/frequency
velocity = distance/time
velocity = wavelength x frequency
velocity = distance ~ time
velocity = wavelength/frequency

Answers

Answer:

velocity = distance/time

velocity = wavelength × frequency

Both of these are commonly known equations to calculate velocity with different variables.

When equal moles of an acid and a base are mixed, after reaction the two are compounds are said to be at the _______________. Select one: Indicator point Stoichiometric point Equilibrium point End point

Answers

Answer:

when equal moles of an acid and base are mixed,after reaction the two are compounds are said to be at the Equivalent point.

Karl-Anthony is trying to plate gold onto his silver ring. He constructs an electrolytic cell using his ring as one of the electrodes. He runs this cell for 94.3 minutes at 205.3 mA. How many moles of electrons were transferred in this process

Answers

Answer:

0.012 moles of electrons were transferred

Explanation:

We can find the number of electrons transferred from the time in seconds and the current in Amperes using the equation:

n = I*t / F

Where n are moles of electrons transferred

I is current in Amperes = 0.2053A

t is time in seconds:

94.3min*(60s/1min) = 5658s

F is faraday constant 96485A*s/mol

Replacing:

n = 0.2053A*5658s / 96485A*s/mol

n = 0.012 moles of electrons were transferred

Moles are the mass per unit molar mass of compound. The number of moles of electrons that are transferred is 0.012 moles.

What is an electrolytic cell?

An electrolytic cell is a type of electrochemical cell that uses electrical energy from external sources to conduct the chemical energy in a cell.  

The moles transferred in electrolytic cells are measured as:

[tex]\rm n = \rm \dfrac{I\times t}{F}[/tex]

Given,

Current (I) in amperes = 0.2053 A

Time (t) in seconds = 5658 sec

Faraday constant (F) = 96485 A -s/mol

Substituting values in the equation above moles (n) can be calculated as:

[tex]\begin{aligned} \rm n &= \dfrac{ 0.2053 \times 5658 }{96485}\\\\&= 0.012 \;\rm mol\end{aligned}[/tex]

Therefore, 0.012 moles are transferred in this process.

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A runner completes the 300-meter dash in 38 seconds. What is the speed of the runner? Round your answer to the nearest tenth.

Answers

Answer:

x= 300m , 38s

answer is 7.9

Answer:

speed=distance/time

Explanation:

speed=300/38

=7.8947368421

to the nearest tenth=7.9

I don’t know what Ksp and Kf are stand for?

Answers

Answer:

Sorry but I know only what ksf stand for

Explanation:

Ksf stand for solubility product constant

Answer:

ksp stands for solubility product constant .

kf stands for molal freezing point depression constant ..

Explanation:

KSP = The solubility product constant, Ksp​, is the equilibrium constant for a solid substance dissolving in an aqueous solution. It represents the level at which a solute dissolves in solution. The more soluble a substance is, the higher the Ksp value it has .

KF = Kf is a constant for a given solvent. Kf is called the molal freezing point depression constant and represents how many degrees the freezing point of the solvent will change when 1.00 mole of a nonvolatile nonionizing (nondissociating) solute dissolves in one kilogram of solvent.

Determine which choice is an example of an endothermic process.
O A. Lighting a match
B. Respiration
C. Running a gas engine
D. Baking bread

Answers

Answer:

D. Baking bread

Explanation:

In this process, energy is absorbed and in an endothermic process energy is absorbed too.

Baking bread is an example of an endothermic process, therefore option (d) is correct .

What do you mean by endothermic process ?

Endothermic reactions are chemical processes in which the reactants absorb heat from the environment to produce products.

An endothermic reaction is  accompanied by an absorption of heat.

Endothermic  reactions cause a cooling effect by lowering the temperature of the surrounding environment.

A decrease in temperature can be observed with the progression of the reaction. The reaction is non-spontaneous in endothermic reactions .

Baking bread is an example of an endothermic process, hence  option (d) is correct .

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which list only includes terms that describe... both questions please

Answers

The terms that describe sodium atom are;

AtomelementPure substance

The terms that describe propane gas are;

MoleculeCompoundPure substance

Sodium can be described as an element found in the periodic table. Sodium can also be described as an atom as in when we make the statement; 'an atom of sodium'. Sodium can also be regarded as a pure substance as in when we are referring to a substance composed only of sodium atoms.

On the other hand, propane gas can be regarded first as a compound because it is a combination of elements that are chemically combined together. We can also refer to 'a molecule of propane gas' since the substance is molecular in nature. Also, the pure gas (containing no impurity) can be regarded as a pure substance.

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A nuclease enzyme breaks the covalent bond originally connecting the phosphate to the 5' carbon in a nucleic acid. After allowing this enzyme to completely digest the nucleic acid down to monomers, you perform tests to determine where the phosphate is attached to each monomer. Where do you expect to find this phosphate

Answers

Answer:

The phosphate will remain attached to the 5' carbon of the deoxy or the ribose sugar in the nucleic acid monomers.

Explanation:

The structure of nucleic acid polymers is built up from monomers of nucleotides.

A nucleotide consists of a sugar backbone which is either a ribose or deoxyribose sugar, a nitogenous base which is either a purine or pyrimidine, and a phosphate group. The nitrogenous base is attached to the carbon number 1 or C-1 of the sugar backbone by a covalent bond. The phosphate group on the other hand is covalently attached to the carbon number 5 or 5' carbon of the sugar backbone.

When polymers of nucleic acids are formed, the phosphate at the 5' carbon of the sugar backbone is covalently linked in a phosphodiester bond to the 3' carbon of the sugar backbone in another nucleotide molecule, thus extending the strands of the nucleic acid molecule.

Nucleases are enzymes that break down the phosphodiseter bonds in nucleic acids resulting in nucleotide monomers. After complete digestion ofmthe nucleic acid polymer by nucleases, the phosphate will remain attached to the 5' carbon of the deoxy or the ribose sugar in the nucleic acid monomers.

At what velocity (m/s) must a 20.0g object be moving in order to possess a kinetic energy of 1.00J

Answers

Answer:

10 ms-1

Explanation:

Kinetic energy = 1/2 × m × v^2

1 = 1/2× 20 ×10^ -3 × v^2

v ^ 2 = 100

v = 10 ms-1

note : convert grams in to kg before substitution as above

The velocity will be "10 m/s".

Given:

Kinetic energy,

K.E = 1.00 J

Mass,

m = 20.0 g

We know the formula,

→ [tex]K.E = \frac{1}{2} mv^2[/tex]

By putting the values, we get

       [tex]1 = \frac{1}{2}\times 20\times 10^{-3}\times (v)^2[/tex]

     [tex]v^2 = 100[/tex]

       [tex]v = \sqrt{100}[/tex]

       [tex]v = 10 \ m/s[/tex]

Thus the above response is correct.

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You are titrating 24.3 mL of 2.00 M HCl with 1.87 M NaOH. How much NaOH do you expect to have added when you reach the equivalence point?

26.0 mL

15.4 mL

13.4 mL

Answers

Answer:

26mL

Explanation:

NaOH+HCl= NaCl+H2O

nHCl=0.0243*2=0.0486

nNaOh=nHCl

VNaOH=0.0486/1.87=0.026l=26ml

Answer:

26.0 mL

Explanation:

State the different radiations emitted by radioactive elements.

Answers

Answer:

gamma rays , alpha particles , beta particles , neutrons

So the different types of the three main types of radiation given off during radioactive decay, two are particles and one is energy; scientists call them alpha, beta and gamma after the first three letters of the Greek alphabet. Alpha and beta particles consist of matter, and gamma rays are bursts of energy.

Hope this helps :))

arrange the metals sodium,copper, and magnesium in the decreasing order of their reactivity​

Answers

Answer:

sodium>magenisium>copper

s-Block compounds give a characteristic flame colour in the flame test. Based on this, can you give one use of s-block compounds?​

Answers

Answer:

Lithium is used in making electrochemical cells.

A bio catalyst that increases the rate of the reaction without being changed
a) Aluminum oxide. b) Silicon dioxide. c) Enzyme. d) Hydrogen peroxide
43. What is the
than the reaction substrate.
42. A

Answers

Explanation:

Enzymes are proteins functioning as catalysts that speed up reactions by lowering the activation energy. A simple and succinct definition of an enzyme is that it is a biological catalyst that accelerates a chemical reaction without altering its equilibrium.

Three bonding pairs around a central atom results in a ________. A. octahedral B. trigonal planar compound C. tetrahedral compound D. linear compound

Answers

Answer:

B

Explanation:

because it is a trigonal planar compound

Three bonding pairs around a central atom results in a trigonal planar compound. Option B is correct.

In a trigonal planar arrangement, the central atom is surrounded by three bonding pairs of electrons, forming a flat, triangular shape. The bond angles between the bonding pairs are approximately 120 degrees.

This molecular geometry is observed when a molecule has a central atom with three bonded pairs and no lone pairs. Examples of compounds with  trigonal planar geometry include boron trifluoride (BF₃) as well as formaldehyde (H₂CO).

The other options are not correct for a molecule with three bonding pairs;

Octahedral refers to a molecular geometry with six bonding pairs around a central atom.

Tetrahedral corresponds to a molecular geometry with four bonding pairs around a central atom.

Linear represents a molecular geometry with two bonding pairs around a central atom.

Hence, B. is the correct option.

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(URGENT FOR BRAINLIEST!!)
The diagram below shows the movement of Earth plates.

The picture shows two Earth plates one beside the other. The plate on the left is shown moving towards the right and the plate

Which of these features is most likely formed as a result of the movement of Earth plates shown in the diagram? (2 points)


a canyon

a fault

a mountain

a ridge

Answers

Answer:

mountain

Explanation:

when plates move towards each other they create mountains

Which is the best interpretation of the two flat portions of the graph?

Answers

In those portions, the heat supplied to the substance by the heater does not lead to a temperature rise as intermolecular forces are broken.

When a substance is heated, we normally expect that its temperature will rise as a consequence.

However, heat may be supplied to a substance but its temperature does not rise owing to the fact that the heat energy supplied is used to break intermolecular bonds.

This occurs during fusion and boiling. The heat supplied at these point does not result in temperature rise since it is used to break intermolecular bonds. The temperature remains steady during these processes as shown by the two flat portions on the graph in the image attached to the question. This heat supplied is known as the latent heat.

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Answer:

The answer for me was "These show where changes of state are occuring"

Explanation:

I got it right

Titration of 25.0 mL of an HCl solution of unknown concentration requires 14.8 mL of 0.100 M NaOH. What is the molar concentration of the HCl solution

Answers

M1V1 = M2V2
M1 = 0.100 M NaOH
V1 = 14.8 mL NaOH
M2 = ?
V2 = 25.0 mL HCl

(0.100 M)(14.8 mL) = M2(25.0 mL)

M2 = 0.0592 M HCl

Question 4
18 g of carbon dioxide contains how many oxygen atoms?

Answers

Answer:

4.92×10²³ atoms of oxygen.

Explanation:

We'll begin by calculating the number of mole of oxygen in 1 mole of CO₂. This can be obtained as follow:

1 mole of CO₂ contains 2 mole of oxygen.

1 mole of CO₂ = 12 + (2×16)

= 12 + 32

= 44 g

Thus,

44 g of CO₂ contains 2 moles of oxygen.

Next, we shall determine the number of mole of oxygen in 18 g of CO₂. This can be obtained as follow:

44 g of CO₂ contains 2 moles of oxygen.

Therefore, 18 g of CO₂ will contain

= (18 × 2)/ 44 = 0.818 mole of oxygen.

Finally, we shall determine the number of atoms in 0.818 mole of oxygen. This can be obtained as follow:

From Avogadro's hypothesis,

1 mole = 6.02×10²³ atoms.

Therefore,

0.818 mole = 0.818 × 6.02×10²³ atoms.

0.818 mole of oxygen = 4.92×10²³ atoms.

Thus, 18 g of CO₂ contains 4.92×10²³ atoms of oxygen.

WHAT WOULD THE RIGHT OPTION??

how many resonance structures of benzene are known?
A) 3
B) 4
C) 5
D) 6 ​

Answers

Answer:

C) 5

Step-by-step explaination:

Benzene has 5 resonance structures.

How many grams of H₂SO₄ are contained in 2.00 L of 6.0 M H₂SO₄?

Please explain and show work.

Answers

Answer:

1176 grams

Explanation:

nH2SO4 =2*6=12 mol

mH2SO4=12*98=1176 grams

Answer:

solution given:

molarity of H₂SO₄=6 M

volume=2L

no of mole =6M*2=12mole

we have

mass =mole* actual mass=12*98=1176g

the mass is 1176g.

CH3CH2OH
______ions
in an aqueous solution.
А
forms
B
does not form

Answers

Answer:

When ionic compounds dissolve, they break apart into ions which are then able to conduct a current ( conductivity ). ... Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions.

Explanation:

Ethanol is an organic compound with an alcoholic functional group and is nonelectrolytes. Ethanol (CH₃CH₂OH) does not form ions in an aqueous solution. Thus, option B is correct.

What are nonelectrolytes?

Nonelectrolytes are substances that do not dissociate readily to yield ions and also are poor conductors of electricity and heat due to a lack of charged ions.

Ethanol is a nonelectrolyte that does not show conductivity and can be dissolved in water without producing ions. They cannot forms ions upon dissociation as covalent bonds are present.

Instead of ions that have covalent compounds that lack the ability to transfer the electron to conduct the electrical charge. Glucose, ethanol, etc. are some examples of a nonelectrolyte.

Therefore, option B. ethanol does not form ions is the correct blank.

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If you dissolve 0.1 mol of formic acid in 1 L of water, ther esulting solution contains 0.004 mol of H₃O+. Based on this information, is formic acid a strong acid, or is it a weak acid?

Please explain!

Answers

In an ideal case, the acid would completely protonate. such an acid would be a strong acid.  Dissociation of Formic acid looks like:

HCOOH + H₂O → COOH⁻ + H₃O⁺

one mole of formic acid should give one mole of Hydronium(H₃O⁺) ions

similarly, 0.1 moles of formic acid should produce 0.1 moles of hydronium ions. but we know that it is not the case, a much lesser amount is actually formed.

Which means that Formic acid did not completely dissociate into COOH⁻ and H⁺ ions.

Hence, Formic Acid is a weak acid

We know

Any acid

Containing carbon is weak Containing no carbon is strong

Formic acid stands for HCOOH

It contains C means dissociation is less .

The dissociation of H+ is less means acidity is less.

Weak acid
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