chemical reactions can be detected by changes in____. select all that apply. a)temperature.
b)density of the products compared to the reactants.
c)color.
d)overall mass of the products compared to the mass of the reactants.

Answer:

Approximately 3.1 × 10²².

Explanation:

Start by considering: how many moles of copper atoms in this 3.3-gram coin?

To answer that, it would be necessary to know the mass of one mole of copper atoms. The mass (in grams) of one mole of copper atoms is numerically equal to the relative atomic mass of copper. Look up the relative atomic mass of copper on a modern periodic table.

In other words, the mass of one mole of copper atoms is equal to 63.546 grams. Hence, the number of moles of copper atoms in the 3.3-gram coin would be equal to

[tex]\displaystyle n = \frac{m}{M} = \frac{3.3}{63.546} \approx 0.0519309 \; \rm mol[/tex].

How many copper atoms would that be? Avogadro's Constant gives the number of particles in one mole.

[tex]N_A \approx 6.023\times 10^{23}\; \rm mol^{-1}[/tex].

Since there are approximately [tex]0.0519309 \; \rm mol[/tex] copper atoms, the number of copper atoms would be

[tex]\displaystyle N = \frac{n}{N_A} \approx \frac{0.0519309}{6.023\times 10^{23}} \approx 3.3 \times 10^{22}[/tex].

The number of moles of copper in a penny of mass 3.3g is about 0.052 moles. By multiplying by Avogadro's number, we find that there are approximately 3.1 × 10²² copper atoms in the penny.

To determine the number of moles of copper in a single penny, you need to know the atomic weight of copper and Avogadro's number. The atomic weight of copper is approximately 63.5 g/mol. So, given that the mass of the penny is 3.3 g, we can use the following conversion to find the number of moles:

moles of copper = mass of copper / atomic weight of copper

moles of copper = 3.3 g / 63.5 g/mol = 0.052 moles.

To find the number of copper atoms, you would multiply the number of moles by Avogadro's number (6.022 × 10²³ atoms/mol), thus:

number of copper atoms = number of moles * Avogadro's number

number of copper atoms = 0.052 moles * 6.022 × 10²³ atoms/mol ≈ 3.1 × 10²² copper atoms.

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Answer: it transfers through conduction, the molecules of the iron are bumping into the molecules of the shirt, giving them energy.

Explanation: conduction is Energy transferred by touching.

Answer:

The answer is chemical properties such as its ability to form chemical bonds

Explanation:

The statement that represents what can be learned by the number of electrons on the outer energy level of an atom is chemical properties such as its ability to form chemical bonds.

Valence electrons in chemistry refers to any of the electrons in the outermost shell of an atom that is capable of forming bonds with other atoms.

The valence electrons of an atom is responsible for its ability to form chemical bonds with other atoms.

The valence electrons of an atom gives no information on the physical property of the element.

Therefore, the statement that represents what can be learned by the number of electrons on the outer energy level of an atom is chemical properties such as its ability to form chemical bonds.

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Answer: 437 g C6H6

Explanation: Solution attached:

1 mole of C6H6 is equal to its molar mass 78 g C6H6.

5.6 moles C6H6 x 78 g C6H6 / 1 mole C6H6

= 437 g C6H6

The mass of C₆H₆ is 436.8 grams.

Given:

Moles of C₆H₆ =5.6 moles

To find:

Mass of C₆H₆ =?

It is defined as given mass over molar mass.

Number of moles =  Given mass / Molar mass

Molar mass of C₆H₆ = 12*6 + 1*6 = 72+6= 78 g/mol

Mass = Number of moles *  Molar mass

Mass = 5.6 moles * 78 g/mol

Mass = 436.8 grams

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Answer:

Animal cell lacks chloroplasts and a cell wall

Explanation:

Unlike animal cells, plant cells have chloroplasts and a cell wall. In a plant cell, the chloroplasts work to use photosynthesis in order to turn light into energy for the plant cell. Animal cells do not utilize light energy, and therefore do not carry out photosynthesis and do not have chloroplasts.

Additionally, the plant cell has a protective cell wall and a cell membrane, while animal cells only have a cell membrane. This is because the plant cells' cell wall provides additional strength and protection against outside factors, such as osmosis.

Both plant and animal cells have nuclei and cytoplasm, but plant cells have additional structures like cell walls, chloroplasts, and a large central vacuole. Animal cells lack these structures.

Plant cells and animal cells have both similarities and differences. Both types of cells have nuclei and cytoplasm. However, plant cells have cell walls and chloroplasts, which allow for photosynthesis, while animal cells do not have these structures. Additionally, plant cells have a large central vacuole, plastids, and plasmodesmata, which are not found in animal cells.

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Answer:

Orbital diagram attached

Explanation:

Lead has an atomic number 82. Which means that it has 82 protons in its nucleus. As we that in a neutral element number of protons are equal to number of electrons. Which that it has also 82 electrons.

Electronic configuration of lead is:

 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f¹⁴5d¹⁰6p²

OR [Xe] 6s²4f¹⁴5d¹⁰6p²

Answer:

not sure but i think that there are 35 atoms.

Have a great day!

Answer:

                     69.036 g of Compound is required to obtain 48.45 g of Oxygen.

Explanation:

                    Let us assume that the total mass of the compound is 100 g. So it means that this compound weighing 100 is composed 70.18 % of Oxygen or among 100 g of this compound 70.18 g is constituted by oxygen only. Hence, we can make a relation as that,

                      70.18 g O is present in  =  100 g of a Compound

So,

         48.45 g of O will be present in  =  X g of a Compound

Solving for X,

                        X  =  100 g × 48.45 g ÷ 70.18 g

                        X  =  69.036 g of Compound

Answer:

455.4 g (NH_4)2 SO_4

Explanation:

Given:

no of moles of (NH_4)2 SO_4 , n=3.45 moles

To find:

The mass (w) of (NH_4)2 SO_4 in 3.45 moles (n)of it.

Molar mass (M) of (NH_4)2 SO_4 = 132 g

No of moles n is given by the formula;

[tex]n =\frac{w}{M}[/tex]

n is no. of moles

w is mass of the compound

M is the molar mass of the compound

Substituting the values in the formula,

[tex]3.45=\frac{w}{132}[/tex]

w=3.45 × 132=455.4g

78.78 g out of 250 g of Thorium-234 would remain after 40 days.

Explanation:

All radioactive samples are unstable in nature and so they will be decaying with time. So the equation of disintegration of the radioactive element is given as

[tex]N=N_{0}e^{-kt}[/tex]

So N is the mass of the radioactive element at time t and [tex]N_{0}[/tex] is the mass of the radioactive element at initial stage. Here k is the disintegration constant and t is the time.

We can determine the disintegration constant from the half life term of any element.

[tex]Half life = \frac{0.693}{k}[/tex]

So, [tex]k = \frac{0.693}{Half life}[/tex]

Since, the half life time of thorium-234 is known to be 24 days. Then, the disintegration constant is

[tex]k = \frac{0.693}{24}=0.028875[/tex] [tex]days^{-1}[/tex]

As the given questions have the initial mass [tex]N_{0}[/tex] as 250 g and t is given as 40 days, then the mass after 40 days will be

[tex]N = 250 * e^{-0.02887*40}= 250 * e^{-1.1548}=78.78 g.[/tex]

Thus, 78.78 g of thorium-234 would remain after 40 days.

To determine how many grams of thorium-234 would remain after 40 days, we need to understand the concept of radioactive decay. Using the formula for remaining mass, the approximate remaining mass would be 28.69 grams.

To determine how many grams of thorium-234 would remain after 40 days, we need to understand the concept of radioactive decay. Thorium-234 undergoes radioactive decay with a half-life of 24.1 days. This means that after 24.1 days, half of the thorium-234 sample would decay.

To calculate the remaining grams after 40 days, we can use the following formula:

Remaining mass of thorium-234 = Initial mass × (1/2)^(number of half-lives)

Substituting the values, we have:
Remaining mass of thorium-234 = 250 g × (1/2)^(40/24.1)

Using a calculator, the remaining mass of thorium-234 after 40 days would be approximately 28.69 grams.

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Explanation:

Diffusion

It is the movement of substances from the region of  higher concentration to lower concentration .

This diffusion is shown almost negligible by solids , a little by liquids and  maximum by gases .

The factors on which diffusion depends :

Applications of diffusion

It helps in the movement of substance in and out from the cell and its components .

It helps in spreading the fragrance when sprayed with some perfume etc .

It helps in dissolving substance in any medium

Etc

Simple diffusion is the movement of molecules from areas of higher concentration to areas of lower concentration.

Simple diffusion is defined as the movement of

Simple diffusion refers to the movement of molecules from an area of higher concentration to an area of lower concentration. This process occurs due to the natural tendency of molecules to move from regions of high concentration to regions of low concentration in order to achieve equilibrium. This movement does not require the assistance of any external energy or transport proteins.

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Final answer:

The first step of the scientific method is to make observations. Through observations, scientists gather information about a natural phenomenon or problem that they want to investigate.

Explanation:

The first step of the scientific method is to make observations. Through observations, scientists gather information about a natural phenomenon or problem that they want to investigate.

For example, a student arrives at class and notices that the classroom is too warm. This observation leads to a question, 'Why is the classroom so warm?'

By making careful observations, scientists can then proceed to form a hypothesis, which is the next step of the scientific method.

Answer:

a) Acid rain

Explanation:

Because the rest are slolutes

Answer:

Grams of fat would be labeled in 1.3 pounds of ground beef are :

= 117.94 grams

Explanation:

STEP 1: Convert pound into grams:

1 pound = 453.6 grams (learn this)

STEP 2 : Calculate the number of grams in 1.3 pound.

Multiply the number by 1.3

1.3 pound = 1.3 x 453.6  grams

1.3 pound = 589.68 grams

STEP 3: Calculate the mass in 20 % percentage of sample.

[tex]20\% of\ x=x\times \frac{20}{100}[/tex]

Here x = 589.68 grams

[tex]20\%\ of\ 589.68 =589.68\times \frac{20}{100}[/tex]

[tex]20\%\ of\ 589.68 =117.93grams[/tex]

= 117.94 grams

To calculate the fat content in 1.3 pounds of 20% fat ground beef, convert the weight to grams and multiply by the fat percentage, resulting in approximately 117.934 grams of fat.

To determine how many grams of fat are in 1.3 pounds of ground beef labeled as 20% fat, we first need to convert the weight from pounds to grams, since fat content is typically labeled in grams.

Step-by-Step Calculation

Convert pounds to grams: 1 pound (lb) is approximately 453.592 grams (g). Thus, 1.3 lbs is equal to 1.3 × 453.592 g.

Calculate the total grams of beef: 1.3 × 453.592 g = 589.669 g of beef.

Calculate the fat content: Since the ground beef is 20% fat, we determine the fat content by multiplying the total weight of the beef by the percentage of fat. That is 0.20 × 589.669 g.

Find the amount of fat in grams: 0.20 × 589.669 g = 117.934 g of fat.

Therefore, there would be 117.934 grams of fat in 1.3 pounds of ground beef with 20% fat content.

72,300 years are required to reduce Plutonium-239 from 1000 g to 125 g.

Explanation:

It is known that 1 kg of anything is equal to 1000 g of the same compound. Also the half life of any radioactive element meant decay of half of the weight of that element after the half life time.

As here the half life time of Plutonium-239 is said to be 24,100 years. This means after the first interval of 24,100 years, the plutonium-239 of 1000 g will reduce to 1000/2=500 g of plutonium. That means only 500 g of plutonium 239 will be present after the completion of first interval of 24,100 years.

Similarly, the second interval of 24,100 years will again reduce the mass from 500 g to 250 g. Then the third interval of 24,100 years will reduce the mass from 250 g to half of it i.e., 125 g of plutonium. Thus, as per the question, the time taken to reduce 1 kg of plutonium to 125 g of plutonium will require three intervals of half life time. Thus , the total time required to reduce the concentration from 1000 g to 125 g is No.of intervals× Half life time.

Total time required to reduce the weight from 1000 g to 125 g = No.of interval ×Half life time

Total time = 3 ×24100 years = 72,300 years.

So 72,300 years are required to reduce Plutonium-239 from 1000 g to 125 g.

It will take 72,300 years for a 1-kilogram sample of Plutonium-239 to decay to 125 grams. We calculate this by determining that three half-lives will occur for the sample to reach the final mass, with each half-life being 24,100 years.

To calculate how long it will take a 1-kilogram sample of Plutonium-239 to decay to 125 grams, we can use the concept of half-lives. Since Plutonium-239 has a half-life of 24,100 years, we know that every 24,100 years, half of the initial amount will remain.

The process of decay is exponential, and we can find the number of half-lives by the equation:

Number of half-lives (n) = log(final amount / initial amount) / log(0.5)

Filling in the amounts (125 grams final amount, 1000 grams initial amount), we get:

Number of half-lives (n) = log(125 / 1000) / log(0.5) = 3

Therefore, the sample will undergo three half-lives to reach the final mass of 125 grams. To find the total time, we multiply the number of half-lives by the half-life of Plutonium-239:

Total time = Number of half-lives × Half-life of the isotope = 3 × 24,100 years = 72,300 years.

It will take 72,300 years for a 1-kilogram sample of Plutonium-239 to decay to 125 grams.

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Answer:

Three chlorine ions

Explanation:

Answer:

it's a i just took the test

YAY :D

Explanation:

Answer:

A

Explanation:

Took test got it right

Answer

and

Explanation:

All the energy in oil, gas, and coal originally came from the sun, which is captured through photosynthesis. The same way that we burn wood to release energy that the trees capture from the sun, we burn fossil fuels to release the energy that ancient plants had captured from the sun.

Hope this answered your question!

Please let me know how I did.

When a mixture of concentrated sulfuric acid, manganese oxide and sodium chloride is warmed, the chlorine gas is formed.

Explanation:

       NaCl + MnO₂ + H₂SO₄ -----> NaHSO₄ + MnSO₄ + H₂O + Cl₂

For balancing the equation

i) 2 Cl atoms are present at right side while 1 atom is present in left side.

Cl atoms get balanced by putting 2 before NaCl.

ii) Now there are 2 Na atoms present at left while 1 atom is present at the right side.

To balance it, put 2 before NaHSO₄.

iii) (SO₄) is 3 units on the right-hand side, 1 on the left-hand side.

Put a 3 before H₂SO₄ on the left-hand side, thus balancing the number of (SO₄) units.

iv) Balance the excess H atoms present at the left side, by putting a 2 before H₂O.

4NaCl + MnO2 + 4H2SO4 ---> MnCl2 + 4NaHSO4 + 2H2O + Cl2

When Manganese oxide reacts with sodium chloride and sulfuric acid, it gets warmed and produces manganese chloride, chlorine gas, sodium bisulfate, and water.

When this mixture is warmed it produces chlorine gas.

Answer:

it should be that I'm pretty sure it's Newton's law

Answer:

Disrupted food webs

increased competition

disrupted life-cycle events

forced relocation

Explanation:

The results of global warming can be devastating for every living organism. Global warming will cause mist of the organisms of a species to die as they will not be able to maintain themselves in such heated environments. As a result, there will be more competition for resources among different organisms. Organisms will be forced to leave their habitats and relocate themselves as a result of global warming.

Answer:

Disrupted food webs

increased competition

disrupted life-cycle events

forced relocation

Explanation:

Answer:

The equilibrium concentration of NH3 =  0.141 mol/L

Explanation:

The balanced equation for the reaction is :

[tex]NH_{4}HS(s)\rightleftharpoons NH_{3}(g)+H_{2}S(g)[/tex]

Here , you have to write the Kc carefully "Don't write SOLID substance in the expression of Kc"

Kc = equilibrium constant for concentration( Solid are not included in the expression)

So, Kc can be written as :

[tex]Kc=[NH_{3}][H_{2}S][/tex]

Now , look at the equation ,

[tex]NH_{4}HS(s)\rightleftharpoons NH_{3}(g)+H_{2}S(g)[/tex]

Let x moles are dissociated from it at equilibrium

[NH4HS](s)            NH3                H2S

1                          0.28                 0      (Initial moles)

1-x                       x + 0.28        x      (Moles at equilibrium)

Calculate the concentration at equilibrium :

Moles of NH3 = 0.28 mol

The concentration of NH3 is calculated using :

[tex]Concentration=\frac{Moles}{Volume(L)}[/tex]

[tex][NH_{3}]=\frac{0.28 +x}{2}[/tex]

Similarly concentration of H2S

[tex][H_{2}S]=\frac{x}{2}[/tex]

Put the value in given equation:

[tex]Kc=[NH_{3}][H_{2}S][/tex]

Kc = 0.00016

[tex]0.00016=\frac{(0.28 +x)(x)}{2\times 2}[/tex]

[tex]0.00016\times 4 =(0.28 +x)(x)[/tex]

[tex]6.4\times 10^{-4}=0.28x +x^{2}[/tex]

[tex]x^{2}+.28x-6.4\times 10^{-4}=0[/tex]

Use the formula of quadratic equation to solve the value of [tex]x=\frac{-b\pm \sqrt{b^{2}-4(ac)}}{2a}[/tex]

Here, b= 0.28 , c= -.00064 and   a = 1

you get ,

x = 0.002267 mol/L

or

[NH3] =  (x + 0.28)/2 = 0.002267 + 0.28

[NH3] = 0.2822/2 mol/L

[NH3] = 0.141 mol/L

Answer:it doesn’t

Explanation:

Answer:

Subscript

Explanation:

Atoms in a chemical formula are represented by a subscript.

Answer: The answer is D

Explanation:

So there is 2K + 2H2O --> 2KOH + 1H2

2Potassium +  2Water ---> 2Potassium Hydroxide + 1Dihyrogen

2 moles of NaOH dissolved in 1 litre of solution is the solution with more concentration.

Answer: Option A

Explanation:

Concentration of solution is the measure of the amount of solute dissolved in the solvent of the solution. So this is measured using the molarity of the solution. Molarity is determined as the number of moles of the solute present in the given amount of solvent.

[tex]\text {Molarity}=\frac{\text {Moles of solute}}{\text {Amount of solvent }}[/tex]

In this present case, the option A gives the molarity of 2 M as

[tex]\text {Molarity}=\frac{2}{1}=2 M[/tex]

But the second option, mass of NaOH is given. So we have to determine the molarity. First we have to find the molar mass of NaOH. We know that 1 mole of NaOH will contain 40 g/mole.

1 g of NaOH = 40 g of NaOH

1 g of NaOH = 1/40 moles

So 2 g of NaOH will contain [tex]\frac{2 g}{40 g/mole}[/tex] which is equal to 0.05 moles of NaOH.

Thus, the molarity of 2 g of NaOH will be

Molarity = [tex]\frac{0.05 moles }{1 L}[/tex]=0.05 M

Thus, the option A is having higher concentration as the molarity is more for 2 moles of NaOH dissolved in 1 l of solution.

Answer:

The true statement is

An element is made of only one kind of atom.

Explanation:

An element is made of only one kind of atom. For example if we take element carbon it  is made of carbon atoms only .

The other atatements are false.

Positively charged atoms lose electrons and don't gain electrons.

A molecule can also be made of two or more  atoms of the same element. Eg H₂, P₄, Cl₂ etc.

Protons and neutrons are found in the nucleus of the atom and electrons are present outside the nucleus.

Answer: its 3

Explanation:

Answer:

3 has the highest temperature

Explanation:

Just took the test hope this helps. Leave a thanks please

Answer:

C₂HO₂Br₃

Explanation:

Data given

Carbon = 8.09%

Hydrogen = 0.34%

Oxygen = 10.78%

bromine = 80.78%

Empirical formula = ?

Solution:

First find the masses of each component

Consider total compound is 100g

As we now

mass of element = % of component

So,

8.09 g of C = 8.09% of Carbon

0.34 g og H = 0.34% of  Hydrogen

10.78 g of O =  10.78% of Oxygen

80.78 g of bromine = 80.78% of bromine

Now convert the masses to moles

For Carbon

Molar mass of C = 12 g/mol

            no. of mole = mass in g / molar mass

Put value in above formula

            no. of mole = 8.09 g/ 12 g/mol

            no. of mole = 0.674

mole of C = 0.6742

For Hydrogen

Molar mass of H = 1 g/mol

              no. of mole = mass in g / molar mass

Put value in above formula

              no. of mole = 0.34 g/ 1 g/mol

               no. of mole = 0.34

mole of H = 0.34 mole

For Oxygen

Molar mass of O = 16 g/mol

              no. of mole = mass in g / molar mass

Put value in above formula

              no. of mole = 10.78 g/ 16 g/mol

               no. of mole = 0.674

mole of O = 0.674 mole

For Br

Molar mass of Br = 80 g/mol

             no. of mole = mass in g / molar mass

Put value in above formula

              no. of mole = 80.78 g/ 80 g/mol

              no. of mole = 1.0098

mole of Br = 1.0098 moles

Now we have values in moles as below

C = 0.6742

H = 0.34

O = 0.674

Br = 1.0098

Divide the all values on the smallest values to get whole number ratio

C = 0.6742 / 0.34 = 1.983 ≅ 2

H = 0.34 / 0.34 = 1

O = 0.674 /0.34 = 1.983 ≅ 2

Br = 1.0098 / 0.34 = 2.97 ≅ 3

So all have round value 1 mole

C = 2

H = 1

O = 2

Br = 3

So the empirical formula will be C₂HO₂Br₃ i.e. all 3 atoms in simplest small ratio

The empirical formula of the compound is CH₂OBr.

The empirical formula can be determined by finding the ratio of the number of atoms of each element in the compound. To find the empirical formula, we first convert the percentages to grams. Using the given percentages, we can assume we have 100 grams of the compound. Hence, we have 8.09 grams of carbon, 0.34 grams of hydrogen, 10.78 grams of oxygen, and 80.78 grams of bromine.

Next, we convert the grams to moles by dividing each mass by the atomic weight of the respective element from the periodic table. The atomic weights are approximately 12.01 g/mol for carbon, 1.01 g/mol for hydrogen, 16.00 g/mol for oxygen, and 79.90 g/mol for bromine.

After finding the number of moles for each element, we divide each value by the smallest number of moles to get a simple whole number ratio. In this case, the smallest number of moles is 0.0816 moles, which corresponds to carbon. Hence, the ratio is approximately C₁H₀.₀₅ O₀.₂₇ Br₁, which simplifies to CH₂OBr.

Lithium and Iodine will likely form an ionic bond. Lithium, a metal, will lose an electron while Iodine, a non-metal, will gain that electron, resulting in a stable electron configuration and the creation of an ionic bond.

The formation of ionic bonds typically occurs between a metal and a non-metal element due to the transfer of electrons from the metal to the non-metal. In this case, Lithium (Li) and Iodine (I) will likely form an ionic bond. Lithium, a metal, tends to lose an electron while iodine, a non-metal, tends to gain an electron, to achieve a stable electron configuration. This exchange of electrons leads to the formation of an ionic bond with Lithium becoming a positive ion (Li+) and Iodine becoming a negative ion (I-).

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Final answer:

A measuring device is used to determine physical quantities with accuracy and precision, while a holding device is used for support and stability.

Explanation:

In physics, a measuring device is used to determine physical quantities such as length, mass, volume, and voltage. These devices are designed to provide accurate and precise measurements by using standardized units and scales. Examples of measuring devices include rulers, balances, graduated cylinders, and voltmeters.

A holding device, on the other hand, is used to secure or support an object or component during a process or experiment. It is not intended for measuring physical quantities but rather for stabilizing or immobilizing an object in a particular position or orientation. Common examples of holding devices are clamps, vices, and fixtures.

So, the main difference between a measuring and a holding device is their purpose. A measuring device is used for measurement and quantification, while a holding device is used for support and stability.