Potassium-40 has a half-life of 1.25 billion years (by) and decays to argon-40. how old is a fossil that has a 40k/40ar ratio of ~ 26%?

Answers

Answer 1
You can do a very quick estimation by telling the ~ 26% is close to 25%, end then two half-life have passed: one from 100% to 50% concentration, and other from 50% to 25% concentration. So, 2 * 1.25 billion years = 2.50 billion years.

The answer, then is that the fossil is 2.50 by old.

Given that this method has an accuracy of +/- 10% this answer is good enough.

For didactical purposes, I am goint to show you the exact procedure.

C = Co * e^ (- kt)

Half-life time => C = Co / 2

=> C / Co = (1/2) = e ^ (-kt)

=> -kt = ln(1/2) => kt = ln(2)

t = 1.25 by => k (1.25) = ln(2) => k = ln(2) / 1.25 = 0.5545

=> C/Co = e ^ (-kt)

In the problem C/Co = 26/100 => 0.26 = e^ (-0.5545t)

=> -0.5545t = ln (0.26)

=> t = - ln (0.26) / 0.5545 = 2.43 by.

So with the exact procedure you obtain 2.43 by while with the estimation that ~26% is close to 25% you obtain 2.50 by.


Related Questions

Which statements describe kinetic and potential energy? Check all that apply. Energy can be stored in the position of an object. Energy is not present in a moving object. Energy can be stored in the position of the particles that make up a substance. Energy exists as movement of the particles of a substance. Energy is greater in faster-moving particles than in slower-moving particles. Energy is lower in objects with greater mass than in objects with less mass.

Answers

Kinetic and potential energy is the form of energy, the object exists. Energy is neither created nor destroyed. It changes from one form to another.

The energy of the moving object is termed Kinetic energy. However, the stored energy or the energy of the object in the stationary position is the Potential energy.

Energy can be stored in the position of an object.

The statement is true, as the stored energy is the potential energy.

Energy is not present in the moving object.

This statement is false, as the moving object energy is the kinetic energy of the object.

Energy can be stored in the position of the particles that make up a substance.

The statement is true, as the potential energy of the object is stored in its particles.

Energy exists as the movement of the particles of a substance.

The movement of the particle of a substance will result in the kinetic energy of the substance. Thus the statement is true.

Energy is greater in faster-moving particles than in slower-moving particles.

The statement is true, as fast the object moves more energy will be required and the conversion of more potential energy to kinetic energy takes place.

Energy is lower in objects with greater mass than in objects with less mass.

The statement is false, as the greater the mass of the object, the greater will be the number of particles and more energy will be stored.

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Is the polar head of a soap molecule more attracted to calcium or sodium ions?

Answers

The polar head of a soap molecule would be more attracted to calcium ions than that of sodiu ions. Sodium ions has a positive charge only. It has a +1 charge. While, calcium ion carries a double positive or a +2 charge. So, the negative charged polar part of a soap molecule would be more attracted to the double positive charge than a positive charge only. This is true for a magnesium ion also since it also has a double positive charge. Soap molecules has properties for both polar and non-polar which can be found at the end of a molecule. When it is in water, it forms micellar structure where the polar end would be facing or attracted to water while the non-polar end would move away from the water.

The number of valence electrons in an element with electron configuration 1s2 2s2 2p6 3s2 3p4 is ________.

Answers

Answer:

6

Explanation:

The given electron configuration 1s² 2s² 2p⁶ 3s² 3p⁴.

The valence shell of an atom is the outermost orbit. Here the valence shell is 3 with electrons occupying the  s and p orbitals.

The s orbital has 2 electrons and the 3p orbital has 6 electrons. So adding all the electrons in the 3s and 3p orbital we have a total of 6 electrons in the 3rd valence shell.

The number of valence electron in the element is 6 electrons

Valence electron(s) are the electrons located on the outermost shell of an atom.

From the question given above, we obtained:

Electronic configuration => 1s² 2s²2p⁶ 3s²3p⁴

The valence shell is => 3s²3p⁴

Total electron in valence shell = 2 + 4

Total electron in valence shell = 6 electrons

Therefore, the number of valence electron in the element is 6 electrons.

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Friction and motion occur at the same time.

True
False

Answers

true, friction is the force that opposes motion.

How many lone pairs are on the central atom in BCl3

Answers

There are no lone pairs

What type of energy is stored for use at a later time? Bond energy Free energy Kinetic energy Potential energy

Answers

Potential energy
_____________
 It is potential energy

Consider the incomplete reaction below.

NaOH + X mc005-1.jpg NaCH3COO + H2O

What is X in this reaction?
NH4OH
H3PO4
H2CO3
CH3COOH

Answers

x is CH3COOH. Beacuse its makes the equation balanced

    NaOH  + X → NaCH3COO  + H2O

In the incomplete  reaction    above    x  is CH3COOH  (  acetic acid)


Explanation

 carboxylic   acid react   with metal hydroxide  to form salt  and water.  sodium hydroxide (NaOH) react with    acetic acid to form  sodium  acetate ( NaCH3COO and  water H2O.

NaOH + CH3COOH  →  NaCH3COO (salt)  + H2O

Why does every element except hydrogen need at least one neutron in its nucleus?

Answers

It needs attractive force from the strong nuclear interaction to counter the electrostatic repulsion between the protons .

Two or more than two atoms with different physical or chemical properties can not combine together to form an element.  By removing the repulsions among protons inside the nucleus, neutron provide the stability to an atom.

What is element?

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.

An atom of element contains neutrons and protons in the nucleus and electron that revolves around the nucleus. The purpose of neutron is to provide stability to an atom by minimizing the repulsion between protons inside the nucleus.

Therefore by removing the repulsions among protons inside the nucleus, neutron provide the stability to an atom.

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Which is not one of the eight most common elements in Earth’s continental crust? silicon carbon aluminum oxygen

Answers

carbon. is the answer

Answer:  Carbon

Explanation:  The top layer of the earth is known as lithosphere which contain the crust of the earth.

The earths crust contain some of the most abundant elements which facilitate the human life .

In this series of top abundant elements found in Earths continental crust, Oxygen scores the first position and after that Silicon comes as second and Aluminum bags the third position and so on.

Therefore, carbon does not even come in the top 10 elements which are most abundant in the earths crust.

Zinc and magnesium metal each reacts with hydrochloric acid to make chloride salts of the respective metals, and hydrogen gas. a 11.20-g mixture of zinc and magnesium produces 0.6854 g of hydrogen gas upon being mixed with an excess of hydrochloric acid. determine the percent magnesium by mass in the original mixture.

Answers

Final answer:

The percent magnesium by mass in the original mixture is 153.2%.

Explanation:

To determine the percent magnesium by mass in the original mixture, we need to calculate the mass of magnesium in the mixture. We know that the total mass of the mixture is 11.20 g, and 0.6854 g of hydrogen gas is produced.

First, we need to calculate the moles of hydrogen gas produced. Since 1 mole of hydrogen gas is produced for every 2 moles of magnesium, we can use the molar mass of magnesium (24.31 g/mol) to find the moles of magnesium:

moles of Mg = (0.6854 g H₂) x (1 mol Mg / 2 mol H₂) x (24.31 g/mol) = 0.704 mol Mg

Next, we can calculate the mass of magnesium:

mass of Mg = (0.704 mol Mg) x (24.31 g/mol) = 17.12624 g Mg

Finally, we can calculate the percent magnesium by mass:

percent magnesium = (mass of Mg / total mass of mixture) x 100% = (17.12624 g / 11.20 g) x 100% = 153.2%

What is the concentration (m) of ch3oh in a solution prepared by dissolving 16.8 g of ch3oh in sufficient water to give exactly 230 ml of solution?

Answers

The Molarity concentration is expressed in units of moles / L. So let us first determine the number of moles of CH3OH, and then divide that amount by the total volume of 0.230 L of solution.

To determine the number of moles of CH3OH, divide the weight in grams of CH3OH by the molecular weight of CH3OH: (MW of CH3OH = 32 g / mol)

number of moles = 16.8 g / (32 g / mol)

number of moles = 0.525 mol CH3OH 

Then we calculate for molarity:

Molarity = 0.525 mol CH3OH / .230 L

Molarity = 2.2826 mol / L

Molarity = 2.28 M

The molarity of a solution prepared by dissolving 16.8 g of CH₃OH in sufficient water to give exactly 230 mL of solution is 2.28 M.

The concentration of CH₃OH in a solution can be determined by calculating its molarity, which is the number of moles of solute per liter of solution. To find the molarity, we first need to convert the mass of CH₃OH to moles. The molar mass of CH₃OH (Methanol) is 32.04 g/mol.

Step 1: Convert the mass of CH₃OH to moles using its molar mass.
16.8 g CH₃OH ×1 mol CH₃OH / 32.04 g CH₃OH = 0.524 moles CH₃OH

Step 2: Convert the volume of the solution from milliliters to liters.
230 mL ×1000 mL/L = 0.230 L

Step 3: Calculate the molarity of the solution.
0.524 moles CH₃OH / 0.230 L = 2.28 M

A solution which contains maximum solute at a given temperature is

Answers

I believe the solution that contains the maximum amount of solute present within it at a given temperature, would be referred to as saturated. No more solute can dissolve or be mixed within the solvent and have it dissolved at that temperature.

Answer: saturated

Explanation:

Saturated solution is defined as the solution in which no more solute particles can be dissolved in the solvent and thus contain maximum solute at a given temperature.

Unsaturated solution is defined as the solution in which more solute particles can be dissolved in the solvent at any particular temperature.

Supersaturated solution is defined as the solution in which more amount of solute particles is present than the solvent particles and thus the solute is in precipitated form.

What is the very thick liquid called which is found deep underground and is refined before use?

Answers

Oil. Before it is refined it is called crude oil.

Answer: oil

Explanation:

How many grams of hydrochloric acid will react completely with a block of gold that is 3.2 cm by 3.8 cm by 2.8 cm, if the density of gold is 19.3 g/ml?

Answers

The chemical reaction would be:

2Au + 2HCl = 2AuCl + H2

First, we need to determine the mass of gold that is used in the reaction. We do this by multiplying the volume of the block of gold to its density. We do as follows:

Mass of Au = (3.2 cm) (3.8 cm) (2.8 cm) ( 1 mL / 1 cm^3) ( 19.3 g/ mL) = 657.1264 g Au

From the molar mass of Au which is 197 g/mol, we convert the mass of Au to moles and relate HCl by using the balanced reaction. We do as follows:

657.1264 g Au ( 1 mol / 197 g ) ( 2 mol HCl / 2 mol Au ) ( 36.46 g / mol ) = 121.62 g HCl

Sulfuric acid is a component of acid rain formed when gaseous sulfur dioxide pollutant reacts with gaseous oxygen and liquid water to form aqueous sulfuric acid. part a write a balanced chemical equation for this reaction. express your answer as a chemical equation. identify all of the phases in your answer.

Answers

2SO₂(g) + O₂(g) + 2H₂O(aq) → 2H₂SO₄(aq)

Answer:

The chemical reaction is :

[tex]2SO_2(g)+O_2(g)+2H_2O(l)\rightarrow 2H_2SO_4(aq)[/tex]

Explanation:

When sulfur dioxide gas reacts with oxygen gas and liquid water it gives aqueous solution of sulfuric acid.

This is reason behind the acidic nature of the rain water during acid rain.The chemical reaction is given as:

[tex]2SO_2(g)+O_2(g)+2H_2O(l)\rightarrow 2H_2SO_4(aq)[/tex]

According to stoichiometry, 2 moles of sulfur dioxide gas reacts with 1 mole of oxygen gas and 2 moles of water to give 2 moles of aqueous sulfuric acid.

When sodium and chlorine form an ionic compound, the chemical formula is written as __________.
a. ClNa
b. NaCl
c. Cl2Na
d. Na2Cl

Answers

The correct answer is NaCl. In fact it is known as table salt. Hope this helps

How far he drove, in miles?

Answers

the answer is C (xy)

Write a description of a water molecule as it goes through the complete water cycle. you should include the processes of precipitation, evaporation, condensation, and runoff

Answers

Step 1: Precipitation:
At the right conditions of preesure and teperature, large droplets of water are formed from the small ones in clouds and rain falls. This process is called precipitation.
Step 2: Runoff:
The rainfall usually strams down the earth and flows down lakes, rovers and oceans. This process is called runoff.
Step 3: Infiltration:
This process occurs when the rain water goes below the surface of the earth into the soil and the rocks that are beneath the surface.
Step 4: Transpiration:
The water that went through the soil is absorbed by the roots of the plants. It makes its way through the stem until it reaches the leaves where it evaporates and adds to the already existing water vapor in the air. This process of evaporation is called transpiration.
Step 5: Evaporation:
This process occurs when water changes from the liquid state to the gaseous state.
Step 6:Condensation:
This process occurs when the water chanfes from the gaseous state into the liquid state.
Step 7: Precipitation again...and the cycle repeats
Final answer:

The journey of a water molecule through the water cycle begins with evaporation or sublimation, followed by condensation forming clouds. Afterward, precipitation brings the water back to the earth where it becomes part of surface runoff, snowmelt, or infiltrates the soil. Finally, streamflow carries it back to the oceans, completing the cycle.

Explanation:

A water molecule undergoes a fascinating journey as it completes the water cycle. Initiated by the sun's energy, this journey starts with evaporation or sublimation, which are processes that turn surface water or frozen water into water vapor, respectively. The water vapor is then transported into the atmosphere.

As the vapor cools down, the process of condensation takes place, forming clouds consisting of condensed water droplets. Over time, these droplets grow in size and eventually fall to the earth in the form of precipitation (like rain or snow).

Once on earth, the water can take a few different paths. Some fall on tree leaves and evaporate again, some fall directly into bodies of water such as lakes or oceans, while some fall on the ground and become surface runoff or snowmelt. This runoff or snowmelt can infiltrate the soil (subsurface water flow) or flow into streams and rivers (streamflow). These streams and rivers then carry it back into the sea or ocean, completing the cycle.

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Find the approximate atomic mass of a water molecule (h2o). give your answer in atomic mass units rounded to the nearest whole number.

Answers

First step is to get the mass of water molecule in grams:
From the periodic table:
molar mass of hydrogen is 1 
molar mass of oxygen is 16

molar mass of a water molecule = 2(1) + 16 = 18 gm

Now, to convert the gm into amu, all you have to do is multiply the gm you got by Avogadro's number as follows:
mass of water molecule = 18 x 6.22 x 10^23 = 1.1196 x 10^25 amu which is approximately 1 x 10^25 amu

Answer: 18 amu

Explanation:

The atomic mass of hydrogen is 1.008 or 1 (rounded to the nearest whole number)

The atomic mass of oxygen is 15.999 or 16 (rounded to the nearest whole number)

There are 2 hydrogen atoms and one oxygen atom in water.

1+1+16= 18 amu

The ph of a 0.55 m aqueous solution ammonia, nh3, at 25.0°c is 11.50. what is the value of kb for nh3?

Answers

Kb is called the equilibrium constant of basicity. These are actually constants for weak acids. The value for ammonia, NH₃, is actually 1.8×10⁻⁵. This is used to know how much moles of ammonia could react in an equilibrium reaction.

But I'm still gonna show you how it's solved. When we use Kb, we hydrate ammonia. The equilibrium reaction is

NH₃ + H₂O ↔ NH₄⁺ + OH⁻

Now, we use the ICE(Initial-Change-Equilibrium) analysisL

                     NH₃ + H₂O ↔ NH₄⁺ + OH⁻

Initial             0.55     -             0         0
Change           -x        -             +x      +x
--------------------------------------------------
Equilibrium   0.55 - x                 x        x

The variable x here denotes the moles of the substances that is involved in the reaction. They are balanced out by their stoichiometric ratio which is equal to 1:1. Then, we apply the equation for equilibrium constants

Kb = [NH₄⁺][OH⁻]/[NH₃]

the concentration of water is not included because the solution is very dilute. Substituting the equilibrium amounts:

Kb = [x][x]/[0.55-x]

Since we are given the pH, we can use the relationship
pH = 14 - pOH    ;  pOH = -log [OH⁻]
11.5 = 14 - pOH
pOH = 2.5

2,5 = -log [OH⁻]
[OH⁻]=[x] = 3.162×10⁻³

Thus,
Kb = [3.162×10⁻³][3.162×10⁻³]/]0.55- 3.162×10⁻³]
Kb = 1.82 × 10⁻⁵

The equilibrium constant for ammonia[tex]\left({{{\text{K}}_{\text{b}}}}\right)[/tex] is[tex]\boxed{1.82\times{{10}^{-5}}}[/tex].

Further explanation:

Chemical equilibrium is the state in which the concentration of reactants and products become constant and do not change with time. This is because the rate of forward and backward direction becomes equal. The general equilibrium reaction is as follows:

[tex]{\text{A(g)}}+{\text{B(g)}}\rightleftharpoons{\text{C(g)}}+{\text{D(g)}}[/tex]

Equilibrium constant is the constant that relates the concentration of product and reactant at equilibrium. The formula to calculate the equilibrium constant for general reaction is as follows:

[tex]{\text{K}}=\frac{{\left[{\text{D}}\right]\left[{\text{C}}\right]}}{{\left[{\text{A}}\right]\left[{\text{B}}\right]}}[/tex]

Here, K is the equilibrium constant.

The equilibrium constant for the dissociation of acid is known as [tex]{{\text{K}}_{\text{a}}}[/tex]and equilibrium constant for the dissociation of base is known as[tex]{{\text{K}}_{\text{b}}}[/tex].

The expression that relates pH and pOH is given as follows:

[tex]{\text{pH}}+{\text{pOH}}=14[/tex]                                   …… (1)

Rearrange equation (1) to calculate pOH.

[tex]{\text{pOH}}=14-{\text{pH}}[/tex]                                 …… (2)

Substitute 11.50 for the value of pH in equation (2).

[tex]\begin{aligned}{\text{pOH}}&=14-{\text{11}}{\text{.50}}\\&={\text{2}}{\text{.5}}\\\end{aligned}[/tex]

pOH is the measure of hydroxide ion concentration. The formula to calculate pOH is as follows:

[tex]{\text{pOH}}=-\log\left[{{\text{O}}{{\text{H}}^-}}\right][/tex]                              …… (3)

Here,

[tex]\left[{{\text{O}}{{\text{H}}^-}}\right][/tex] is the concentration of hydroxide ion.

Rearrange equation (3) to calculate [tex]\left[{{\text{O}}{{\text{H}}^-}}\right][/tex].

[tex]\left[{{\text{O}}{{\text{H}}^-}}\right]={10^{-{\text{pOH}}}}[/tex]                              …… (4)

Substitute 2.5 for pOH in equation (4).

[tex]\begin{aligned}\left[{{\text{O}}{{\text{H}}^-}}\right]&={10^{-2.5}}\\&=0.0031622\\\end{aligned}[/tex]

The given equilibrium reaction is,

[tex]{\text{N}}{{\text{H}}_{\text{3}}}+{{\text{H}}_2}{\text{O}}\rightleftharpoons{\text{NH}}_4^++{\text{O}}{{\text{H}}^-}[/tex]

The expression of [tex]{{\text{K}}_{\text{b}}}[/tex]for the above reaction is as follows:

[tex]{{\text{K}}_{\text{b}}}=\frac{{\left[{{\text{NH}}_4^+}\right]\left[{{\text{O}}{{\text{H}}^-}}\right]}}{{\left[{{\text{N}}{{\text{H}}_3}}\right]}}[/tex]                                  …... (5)

The equilibrium concentration of both [tex]{\text{NH}}_4^+[/tex] and [tex]{\text{O}}{{\text{H}}^-}[/tex] is the same.

0.0031622 M of [tex]{\text{O}}{{\text{H}}^-}[/tex]is present at equilibrium so 0.0031622 M out of 0.55 M of  has reacted.

The initial concentration of the aqueous solution is 0.55 M. So the concentration of [tex]{\text{N}}{{\text{H}}_3}[/tex] left at equilibrium is calculated as follows:

[tex]\begin{aligned}\left[{{\text{N}}{{\text{H}}_3}}\right]&={\text{Initial concentration of N}}{{\text{H}}_{\text{3}}}-{\text{Reacted concentration of N}}{{\text{H}}_{\text{3}}}\\&={\text{0}}{\text{.55 M}}-{\text{0}}{\text{.0031622 M}}\\&={\text{0}}{\text{.5468378 M}}\\\end{aligned}[/tex]

The value of[tex]\left[{{\text{O}}{{\text{H}}^-}}\right][/tex]is 0.0031622 M.

The value of [tex]\left[{{\text{N}}{{\text{H}}_3}}\right][/tex] is 0.5468378 M.

The value of [tex]\left[{{\text{NH}}_4^+}\right][/tex] is 0.0031622 M.

Substitute these values in equation (5).

[tex]\begin{aligned}{{\text{K}}_{\text{b}}}&=\frac{{\left({0.0031622\;{\text{M}}}\right)\left({0.0031622\;{\text{M}}}\right)}}{{\left({0.546837{\text{8 M}}}\right)}}\\&=1.82861\times{10^{-5}}\\&\approx1.82\times{10^{-5}}\\\end{aligned}[/tex]

Therefore, equilibrium constant for ammonia is[tex]{\mathbf{1}}{\mathbf{.82\times1}}{{\mathbf{0}}^{{\mathbf{-5}}}}[/tex].

Learn more:

1. Calculation of equilibrium constant of pure water at 25°c: https://brainly.com/question/3467841

2. Complete equation for the dissociation of [tex]{\text{N}}{{\text{a}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}[/tex](aq): https://brainly.com/question/5425813

Answer details:

Grade: Senior school

Subject: Chemistry

Chapter: Equilibrium

Keywords: NH3, OH-, NH4+, H2O, equilibrium, kb, pH, pOH, 14, 11.5, 2.5, aqueous solution, 0.0031622 M, 0.5468378 M.

what is the first step when calculating the molar mass of a compound ? A.multiply the total number of atoms in the compound by the compound by the combined molar mass.B.Add the total number of atoms for each element of the compound together.C.add the molar mass for each element of the compound together to find the total.D.multiply the number of atoms for each element in the compound by the molar mass.

Answers

Final answer:

To calculate the molar mass of a compound, first retrieve the atomic masses for each element from the periodic table, multiply them by the number of atoms in the compound, and add the totals.

Explanation:

The first step when calculating the molar mass of a compound is to identify the atomic masses of each element in the compound. You can find these on the periodic table. Once you have the atomic masses, count the number of atoms for each element in the molecular formula. Then, multiply this number by the atomic mass for each element. Finally, add up all of these values to get the total molar mass.

For example, to calculate the molar mass of glucose (C6H12O6), you would do the following:

Identify the atomic masses from the periodic table: Carbon (C) 12.01 g/mol, Hydrogen (H) 1.008 g/mol, and Oxygen (O) 15.999 g/mol.Multiply the number of each type of atom by its atomic mass: (6 \\* 12.01) + (12 \\* 1.008) + (6 \\* 15.999).Add these amounts together to find the total molar mass of glucose.

Which the following is an example of an organic compound that contains an attached carbonyl group at the end of a carbon chain?
ketone
aldehyde
ether
amine

Answers

Most likely the organic compound that contains a carbonyl group bonded near to the end of the chain would be an aldehyde. Unlike a ketone where the carbonyl can be found anywhere within the chain, an aldehyde, is specifically found near the end of the compound, because it would be bonded to H as well.

Answer : The correct option is, Aldehyde.

Explanation :

Ketone group : It is the class of organic compound in which the [tex]-CO[/tex] group is attached to a hydrocarbon is known as ketone.

The general representation of ketone are, [tex]R-CO-R'[/tex].

For example : Acetone, [tex]H_3C-CO-CH_3[/tex]

Aldehyde group : It is the class of organic compound in which the [tex]-CHO[/tex] group is attached to a hydrocarbon is known as aldehyde.

The general representation of aldehyde are, [tex]R-CHO[/tex].

For example : Ethanal , [tex]H_3C-CH_2-CHO[/tex]

Ether group : It is the class of organic compound in which the oxygen is directly attached to the two alkyl group of carbon is known as ether.

The general representation of ether are, [tex]R-O-R^'[/tex].

For example : Dimethyl ether, [tex]H_3C-O-CH_3[/tex]

Amine group : It is the class of organic compound in which the [tex]-NH_2[/tex] group is directly attached to the alkyl group of carbon is known as amine.

The general representation of amine are, [tex]R-NH_2[/tex].

For example : Ethylamine, [tex]H_3C-CH_2-NH_2[/tex]

As per question, aldehyde is an example of an organic compound that contains an attached carbonyl group at the end of the carbon chain.

Hence, the correct option is, Aldehyde.

Which of the following equations violates the law of conservation of mass?

A) 2Al + 6HCl yields 2AlCl3 + 3H2
B) Na2C2O4 + Pb(NO3)2 yields PbC2O4 + 2NaNO3
C) AgNO3 + LiCl yields AgCl + LiNO3
D) 3Ca + 2Cr(NO3)3 yields 3Ca(NO3)3 + 2Cr

Answers

D is the answer.
On the left, there are 3 atoms of Ca, 2 atoms of Cr, 6 atoms of N, and 18 atoms of O.
On the right, there are 3 atoms of Ca, 9 atoms of N, 27 atoms of O, and 2 atoms of Cr.

Answer: Option (D) is the correct answer.

Explanation:

Law of conservation of mass states that energy can neither be created nor it can be destroyed. It can only be transformed from one form to another.

Therefore, in a chemical reaction an equation can only be balanced if the number of reactants equal the number of products because energy required for reactants is utilized in the formation of the products.

For example, [tex]2Al + 6HCl \rightarrow 2AlCl_{3} + 3H_{2}[/tex] is a balanced equation because the number of reactant atoms equal the number of product atoms.

Thus, we can conclude that out of the given options, [tex]3Ca + 2Cr(NO3)_3 \rightarrow 3Ca(NO3)_{3} + 2Cr[/tex] equations violates the law of conservation of mass because number of reactant atoms does not equal the number of product atoms.

The ____ _____ of an element includes atomic number plus the number of neutrons.

Answers

The correct answer for this will be 


atomic
mass
It is the Mass Number!!!!!!!

Predict how the addition of hydrogen gas would affect the initial rate of the reaction below, and explain your prediction.

H2 (g) + I2 (g) -> 2 HI

Answers

The rate of the forward reaction would increase,
Normal Chem explanation: because one of the reactants is now more abundant.
AP chem explanation: Le Chatlier's principle, the reaction works to relieve the new stress, shifting equilibrium to the right

Explanation:

According to Le Chaltelier's principle, when a system is in chemical equilibrium and there occurs any change in concentration, temperature, or pressure then the equilibrium will shift in the direction which is opposing the change.

For example, when concentration of hydrogen gas is increased for the reaction [tex]H_{g} + I_{2}(g) \rightarrow 2HI[/tex] then equilibrium will shift of the right hand side.

That is, formation of product will become faster on increasing the concentration of hydrogen gas.

The density of water is equal to 1.0 g/cm3. a substance with density equal to 0.9 g/cm3 would _____ in water.

Answers

Answer: Float
Explanation: Since water density is 1, substances whose density is less than 1 will float while those whose density is less than 1 will sink.
The more the density of the substance approaches 1, the less part will appear above the water level. Scientist discovered that the density of the substance tell exactly where the substance will be placed.
Example, a substance with density 0.1 then 10% will be below the water line while if the density of the substance is 0.9 then 90% of the substance will be below the water line.

Answer: sink

Explanation:

The Hope diamond has a mass of 44.0 carats and a density of 3.51 g/cm3. What is the volume of the Hope diamond? (Hint: 1 carat = 0.200 g)
A.
2.5 g/cm3
B.
2.5 g
C.
2.5 cm3
D.
2.5 carats

Answers

q=44.0 ct
p=3.51 g/cm³
Δq=0.200 g/ct

m=q×Δq

v=m/p=q×Δq/p

v=44.0×0.200/3.51≈2.5 cm³


C.  2.5 cm³

To find the volume of the Hope diamond, first convert the mass from carats to grams, then divide by the given density. The calculation results in a volume of approximately 2.5 cm³, so the correct answer is option C.

The volume of the Hope diamond can be calculated using its mass and density. First, we convert the mass from carats to grams. Since 1 carat is equivalent to 0.200 grams, the Hope diamond's mass in grams is 44.0 carats × 0.200 g/carat = 8.8 grams. The density formula is density = mass/volume, which can be rearranged to find the volume as volume = mass/density. We use the given density of the diamond, 3.51 g/cm³, to get the volume: volume = 8.8 g / 3.51 g/cm³ = 2.51 cm³. Therefore, the correct answer is 2.5 cm³, so option C is correct.

A weight loss supplement is advertised in several popular beauty and fashion magazines. The advertisements claim that "the supplement can help anyone lose up to 2 inches off their waist in 60 days.” What would be the best way to increase the scientific reliability of this claim?

a.Advertise at local fitness clubs and in fitness magazines. 
b.Find a famous actor or actress to endorse the product.
 
c.Include before and after photos in the advertisement.
d.Have the product tested by an independent organization.

Answers

The answer is d. I think

Answer:  d.Have the product tested by an independent organization.

Explanation:

A scientific claim can be define as a statement which is based upon the results that are obtained after the process of experimentation. The results of the claim are acceptable by the scientific society.

d.Have the product tested by an independent organization. is the correct option. This is because of the fact that the independent organization will test the supplement by several clinical trials. The results obtain will be unbiased and reliable.

Which chemical reaction is a single replacement reaction? A. Ba(ClO3)2 —> BaCl2 + 3O2 B. 2Mg + O2 —> 2MgO C. Zn + CuCl2 —> ZnCl2 + Cu

Answers

I believe the correct answer is C. Zn + CuCl2 —> ZnCl2 + Cu

Do compounds have the same properties as the elements that make them up?

Answers

No, because when elements are chemically combined their properties change

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