Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute. If the half-life for carbon-14 is 5720 years, how old is a wood sample that gives a rate for carbon-14 decay of 7.9 counts per minute?
A. 5.3 x 102 yr.B. 7.6 x 102 yr.C. 1.1 x 103 yr.D. 9.5 x 103 yr.

Answer:

lemme guess is it transportation??

Answer:B. 0.05 mol/dm3

Explanation:

The hydrogen ion concentration in the solution is 2 mol/dm³

The correct answer to the question is Option D. 2 mol/dm³

We'll begin by calculating the molarity of the solution.

Volume = 25 cm³ = 25 / 1000 = 0.025 dm3

Mole of H₂SO₄ = 0.025 mol

Molarity = mole / Volume

Molarity of H₂SO₄ = 0.025 / 0.025

H₂SO₄(aq) —> 2H⁺(aq) + SO₄²¯(aq)

From the balanced equation above,

1 mole of H₂SO₄ contains 2 moles of H⁺.

Therefore,

1 mol/dm³ H₂SO₄ will also contain 2 mol/dm³ H⁺.

Thus, the concentration of Hydrogen ion in the solution is 2 mol/dm³

The correct answer to the question is Option D. 2 mol/dm³

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Answer:

Aluminum even after being an active metal is used as a structural metal due to its toughness, high strength, lightweight, and resistance to the process of corrosion. It is resistant to corrosion as its reactivity gets suppressed due to the formation of an aluminum oxide film which is protective in nature, on its surface. Passivation is the term for the formation of the protective coating.

Answer:

15.26 g of tin

Explanation:

Given that the equation of the process is;

Sn^2+(aq) + 2e ------> Sn(s)

Since 1e = 1F= 96500 C

but q =It

t is in hours so it must be converted to seconds, the SI unit of time

Hence;

119g of tin is deposited by 2 * 96500 C

xg of tin is deposited by 5.29 * 1.30 * 60 * 60

x = 119 * 5.29 * 1.30 * 60 * 60/ 2 * 96500

x = 2946106.8/193000

x= 15.26 g of tin

A current of 5.29 A is passed through a Sn(NO₃)₂ solution for 1.30 hour, the amount of tin plated is 15.26 grams.

Mass of any deposited susbatnce that is obtained by the passing of current will be calculated by using the Faraday's Law as:

W = ECT/F, where

W = required mass of deposited tin

C = current = 5.29 A

T = time period = 1.30hr = 4,680sec

F = faradays constant = 96500C

E = equivalent mass

Equivalent mass will be calculated as:

E = molar mass/charge on atom = 119/2 = 59.5 g/equ

On putting all these values in the above equation, we get

W = (59.5)(5.29)(4680) / 96500

W = 15.26 g

Hence mass of tin is 15.26 g.

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Answer: Thus [tex]\Delta H[/tex] for the conversion of gray tin to white tin is -20.9 kJ

Explanation:

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The final reaction is

[tex]Sn(s, gray)\rightarrow Sn(s, white)[/tex]  [tex]\Delta H=?[/tex]

The intermediate balanced chemical reaction will be,

[tex]Sn(s, gray)+O_2(g)\rightarrow SnO_2(g)[/tex]  [tex]\Delta H^0=-582.78kJ[/tex]    (1)

[tex]Sn(s, white)+O_2(g)\rightarrow SnO_2(g)[/tex]  [tex]\Delta H^0=-580.69kJ[/tex]     (2)    

substarcting (2) form (1) we get

[tex]\Delta H=\Delta H_1-\Delta H_2[/tex]

[tex]\Delta H=-582.78-(-580.69kJ)[/tex]

[tex]\Delta H=-20.9kJ[/tex]

Answer: 4

Explanation: Your counting 4 for each interval. 9+4 =13 13+4 =17 17+4 =21 and so on.

your answer is correct good luckk!!!:)

Answer:

A.

Explanation:

A wave is a disturbance that moves energy from one place to another. Only energy — not matter — is transferred as a wave moves. The substance that a wave moves through is called the medium. That medium moves back and forth repeatedly, returning to its original position. But the wave travels along the medium

Answer: FeO

Explanation:

Answer:

This is not worth 50 points liar

Explanation:

Answer:

Our current model of the atom can be broken down into three constituents parts – protons, neutron, and electrons. Each of these parts has an associated charge, with protons carrying a positive charge, electrons having a negative charge, and neutrons possessing no net charge.

Answer:

Ke1/2mv2

Explanation:

Hope this helps

Answer:

KE 1/2 MV2

ExplanationExplanationExplanationExplanation: hope this helps

Answer:

The vacuole is the storage area of the cell. Most cells have one large vacuole. Vacuoles store food and other materials needed by the cell. They can also store waste products.

Explanation:

Answer:

[tex]\huge\boxed{\sf Option \ B}[/tex]

Explanation:

=> Weight is an attractive force which is exerted on any body.

=> It changes when the object's place changes as it depends upon the acceleration due to gravity ( g = 9.8 m/s ) which changes as we move from place to place.

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

Answer:

1) 4*10^5

2) 3.6*10^5

3) 3.55*10^5

4) 3.550*10^5

5) 3.55000*10^5

Explanation:

1) 4 x [tex]10^5[/tex]

2) 3.6 x [tex]10^5[/tex]

3) 3.55 x [tex]10^5[/tex]

4) 3.550 x [tex]10^5[/tex]

5) 3.55000 x [tex]10^5[/tex]

A number is written in scientific notation when there is a number greater than or equal to 1 1 11 but less than 10 10 1010 multiplied by a power of 10 10.

Significant figures are the number of digits in a value, often a measurement, that contributes to the degree of accuracy of the value.

1) 4 x [tex]10^5[/tex]

2) 3.6 x [tex]10^5[/tex]

3) 3.55 x [tex]10^5[/tex]

4) 3.550 x [tex]10^5[/tex]

5) 3.55000 x [tex]10^5[/tex]

Learn more about scientific notation here:

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#SPJ2

Answer:

c. 6.

Explanation:

Looking at the description given in the question, the elements involved must belong to the p- block of the periodic table and must be in period 5. They also must possess valence electrons in the 5p- orbital.

Now if we look at the p- block of period 5, the following elements satisfy these  requirements; Sr, In, Sn, Sb, Te and I.

Hence there are six of such elements.

The chemical elements that have atoms, in their ground-state, with valence electrons whose quantum numbers are n = 5 and l = 1 are: C. 6.

A valence electron can be defined as the number of electrons that is present in the outermost shell of an atom.

In Chemistry, valence electrons are primarily used to determine whether an atom or group of chemical elements that are found on the periodic table can bond with others.

Based on electronic configuration, quantum numbers of n = 5 and l = 1 simply represents a 6p orbital and there a total of six (6) chemical elements with this orbital, and these include;

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Answer:

Therefore 9 moles of nitrogen are required to produce 18 moles of ammonia.

Answer: State of matter, Subcategory in the metal-metalloid-nonmetal trend, and electrons per shell.

Explanation:

Answer:

It is an amine; it contains a nitrogen atom that will allow nitrogen-hydrogen bonds to form while in water.

Explanation:

The solubility of amines owes largely to the electronegativity difference between nitrogen and hydrogen. Remember that when hydrogen is bonded to highly electronegative element such as nitrogen, intermolecular hydrogen bonding is possible with water molecules. This explains the greater solubility of amines in water.

Ether molecules do have an oxygen atom, however, and engage in hydrogen bonding with water molecules to a lesser extent compared to amines.

Also, amines participate in some acid-base reactions that lead to the formation of diethylammonium hydroxide, an ion which leads to a greater solubility of amines compared to an ether.

Hence, compound A is an amine.

Answer:

hydrogen atom but see the note below.

Explanation:

This is either the most common hydrogen ion or a hydrogen atom. It cannot be either of hydrogen's isotopes.

Answer:

 Hexavalent chromium

Explanation:

Answer: There are two types of crust; oceanic and continental. Oceanic crust is denser and thinner and mainly com​posed of basalt.

Explanation:

The crust This is the outside layer of the earth and is made of solid rock, mostly basalt and granite.  Oceanic crust is denser and thinner and mainly com​posed of basalt.

Answer:

The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere .

Explanation:

Answer:

potassium nitrate= KNO3 ---> KNO2 + O2 and a gas evolution reaction

Explanation:

i think

Answer:

4per m 2

20 mice divided by 5 so it will be 4 per m 2

Answer:

[tex]n_{O_2}=3.84molO_2[/tex]

Explanation:

Hello!

In this case, since the combustion reaction of methanol is:

[tex]CH_3OH+\frac{3}{2} O_2\rightarrow CO_2+2H_2O[/tex]

In such a way, since there is 1:3/2 mole ratio between methanol and oxygen, we can compute the moles of oxygen that are needed to burn 2.56 moles of methanol as shown below:

[tex]n_{O_2}=2.56molCH_3OH*\frac{\frac{3}{2}molO_2}{1molCH_3OH} \\\\n_{O_2}=3.84molO_2[/tex]

Best regards!

Answer:

(C) Vacuum

Explanation:

Explanation:

"A homogeneous mixture has the same proportions of its components throughout any given sample and is also referred to as a solution. Conversely, a heterogeneous mixture has components of which proportions vary throughout the sample."

- Wikipedia

Answer:

chlorine

Explanation:

This is because the electronegativity increases from left to right and decreases from top to bottom of the periodic table.

Answer:

w = -531 kJ

1. Work was done by the system.

Explanation:

Step 1: Given data

Step 2: Calculate the work done (w)

We will use the following expression.

ΔU° = q + w

w = ΔU° - q

w = 156 kJ - 687 kJ

w = -531 kJ

By convention, when w < 0, work is done by the system on the surroundings.

Answer:

Of course, what we today call atoms can be divided into more elementary particles, but not that many.

Explanation: