A student draws a diagram that describes how she thinks people see in the dark. Based on her drawing, she predicts that if people stay
in a totally dark room for a long time, eventually their eyes will adjust to the darkness and they will be able to see.
When she tries this experiment in a totally dark room, it turns out that her prediction was incorrect, and that she is unable to adjust to
the darkness. What should she do with her drawing?
Because her drawing does not accurately represent what really happens, she should make a new version of it that better predicts what she
actually experienced in the dark room.
Because her drawing was not useful in making an accurate prediction, she should discard it and not use drawings anymore to make
predictions.
Because her drawing represents how she thinks the world works, she should not change it but should be confident that she can use it to
make accurate predictions.
O
Because her drawing represents how she thinks the world works, she should use it to make other predictions and keep checking them until
one of them turns out to be correct

Answer:

[tex]40.08 \: grams[/tex]

Explanation:

Therefore, 0.27 moles of calcium to grams is the game as 0.27 moles of Ca to grams, 0.27 moles of calcium to g, and 0.27 moles of Ca to g. Furthermore, the atomic mass of calcium is 40.08. That means that one mole of calcium weighs 40.08 grams (40.08 g/mol).

Wrap an insulator, such as aluminum foil, around the distillation column. The insulation will enable the vapors to ascend to the column's top and exit through the condenser.

Fractional distillation is more effective when the two liquids in the mixture have similar boiling points, typically with a difference of less than 40 degrees Celsius (104 degrees Fahrenheit).

Distilling is a straightforward procedure that involves heating tap water till it turns to vapor. If there are any mineral traces, they are left behind when the vapor returns to becoming water. The resultant condensed liquid is distilled water.

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Most of the energy released in citric acid cycle reactions is conserved in NADH.

What is NADH?

Nicotinamide adenine dinucleotide is a central coenzyme of metabolism. NAD is found in all living cells and is called a dinucleotide because it consists of two nucleotides joined by a phosphate group. One nucleotide contains one adenine nucleobase and one nicotinamide.

NADH stands for "Nicotinamide Adenine Dinucleotide (NAD) + Hydrogen (H)", which occurs naturally in the body and is involved in energy production. NADH produced by the body is involved in the production of energy in the body. Taking NADH supplements can affect blood pressure and have other effects.

Therefore, Most of the energy released in citric acid cycle reactions is conserved in NADH.

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Firstly till 5mL temperature remains constant then suddenly rise in temperature and then again constant.

What is fractional distillation?

Fractional distillation is a type of distillation process that separates a mixture of liquids into its individual components (or fractions) based on their boiling points. This process is commonly used in the petrochemical and oil refining industries to separate large volumes of crude oil into more useful fractions. The process takes advantage of the differences in boiling points of the various components of the mixture, which can vary widely. The process begins by heating the mixture to a temperature where at least one of the components will vaporize. The vapor is then collected and condensed back into the liquid phase. This process is repeated until all of the desired components are collected. This method of separation is extremely efficient and cost-effective compared to other methods, such as liquid-liquid extraction or chromatography.

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The molecular weight (g/mol) of a gas if 35.44 g of the gas stored in a 7.50 l tank exerts a pressure of 60.0 atm at a temperature of 35.5 oc is 1.99 g per mole.( By the ideal gas equation).

the ideal gas law: PV = nRT

P=60.0 atm, V = 7.5 L, T = 35.5 oC = (35.5+273) K = 308.5K

n = 35.44g

PV/RT =n

(60.0)(7.5)/0.821)(308.5) = 17.8 mol

M = 35.44/17.8 = 1.99 g/mol.

Boyle's Law tells us, the volume of gas increases as the pressure decreases. Charles' Law tells us, the volume of gas increases as the temperature increases. And Avogadro's Law tell us ,the volume of gas increases as the amount of gas increases.

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a. The names for the chemical compounds in the task given above are as follows:

b. The formula for the compound given above are:

It is a substance formed between two two or more different elements which are chemical compound together and whose properties are entirely different from the properties of the contribution elements.

In conclusion, we can now confirm from the explanation given above that a compound could be ionic or molecular.

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The flame test, adding HCl, and adding diluted nitric acid to solution are the tests that show that the mixes include potassium carbonate and potassium iodide.

In the food, textile, metal, and rubber sectors, hydrogen chloride (HCl) is frequently employed as a bleach agent to neutralize acidic substances. When discharged into the soil, it is neutral, when it comes in contact with water, it hydrolyzes quickly.

Briefing:

Explanation of how to do a flame test

Potassium ions are present if the flame is lilac/not lilac and yellow if the flame is yellow.

If bubbles of gas occur after adding diluted hydrochloric or nitric acid to the solid, the presence of carbonate ions will allow the gas to bubble through limewater; if the potassium hydroxide turns milky or murky, the presence of carbon dioxide will cause the crystal to dissolve in water.

If there is no reaction with the acid, add diluted nitric acid and silver nitrate solution.

If a precipitate is white, chloride ions are present; if it is yellow, iodine ions are present.

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A gaseous combination of oxygen and nitrogen with a mass percentage of 40.8% has a partial pressure of oxygen of 160.77 mmHg and a total pressure of 345 mmHg.

When we have a combination of two or more gases in a given volume, the word partial pressure is used to indicate the pressure that is brought on by each individual gas in the mixture. The partial pressures of the component gases are added to determine the overall pressure of the gas combination. Ptot = ∑Pi = P1 + P2 + P3 ...

We've been questioned.

A gaseous mixture of O₂ and N₂ contains 40.8% nitrogen by mass, that is, in 100 g of the mixture, there are 40.8 g of N₂. The mass of O₂ in 100 g of the mixture is:

[tex]mo_{2} = 100g - 40.8g = 59.2g[/tex]

We will convert both masses to moles using their molar masses.

[tex]n_{2}[/tex] : 40.8 g * 1 mol / 28.00 g = 1.45mol

O₂ : 40.8 *1 mol / 32.00g = 1.27mol

The mole fraction of O₂ is:

mole fraction of O₂ = nO₂ / n[tex]n_{2}[/tex] +  nO₂ = 1.27 / 1.45 + 1.27 = 0.466

Given the total pressure (P) is 345 mmHg, we can calculate the partial pressure of oxygen using the following expression.

pO₂ = p * mole fraction of O₂

pO₂ = 345 * 0.466

pO₂  = 160.77mmHg

A gaseous mixture of O₂ and N₂ that contains 40.8% nitrogen by mass, and whose total pressure is 345 mmHg, has a partial pressure of oxygen of 160.77 mmHg.

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The lewis structure for carbon tetraiodide, which contains one carbon and four iodine atoms is carbon has four electrons in its valence shell(2s22p2).

Lewis structures, also known as Lewis dot formulas, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show how atoms interact with one another inside of molecules as well as any lone pairs of electrons that may be present. Lewis structures can be found in coordination compounds as well as any molecule having a covalent bond. The Lewis structure was initially introduced by Gilbert N. Lewis in his 1916 article The Atom and the Molecule. Lewis structures expand on the concept of the electron dot diagram by adding lines between atoms to represent shared pairs in a chemical bond.

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Answer:

2mg+2hcl------>mgcl2+h2

Answer: When magnesium reacts with hydrochloric acid, it produces magnesium chloride and hydrogen gas. To write the formula for this reaction, we first need to identify the elements involved and their respective chemical symbols. The chemical symbol for magnesium is Mg, the symbol for hydrochloric acid is HCl, and the symbol for hydrogen is H.

Next, we need to balance the equation by making sure that the number of atoms of each element is the same on both sides of the arrow. In this case, we have one atom of magnesium on the left side of the arrow and one atom of hydrogen on the right side. However, we also have one atom of chlorine on the left side and two atoms of hydrogen on the right side. To balance the equation, we need to add a coefficient of 2 in front of the HCl on the left side, so that the equation becomes:

Mg + 2 HCl -> MgCl2 + H2

This balanced equation shows that for every one atom of magnesium that reacts with two atoms of hydrochloric acid, two atoms of magnesium chloride and two atoms of hydrogen gas are produced.

Answer: well, i'm pretty the mass part came down to how well the atoms all bonded with each other after they were scattered into space after a supernova explosion.

Explanation:

and to be honest... i'm not sure about the gravitational explanation. i assumed that gravitational acceleration depended on an individual object's mass/weight...

The pH of acid is between 0-7 on pH scale while for base pH range is from 7-14. Therefore, the pH of 1.0 x 10⁻³ M of solution is 7.002. pH is a unitless quantity.

pH is a measurement of amount of hydronium ion H₃O⁺ in a given sample. More the value of hydronium ion concentration, more will be the solution acidic.

On subtracting pH from 14, we get pOH which measures the concentration of hydroxide ion in a given solution. pH depend on the temperature. At room temperature pH scale is between 0 to 14. pH of neutral solution is 7.

[H⁺]x[OH⁻] = 10⁻¹⁴

[OH⁻]= 7.5 x 10⁻⁹ M

[H⁺] x  7.5 x 10⁻⁹ = 10⁻¹⁴

[H+]x(  7.5 x 10⁻⁹ +[H+])=10⁻¹⁴

[H+]² + 7.5 x 10⁻⁹ [H+] – 10⁻¹⁴ = 0

[H+] = 0.995x10⁻⁷

pH =-log [H+]

pH =-log [0.995x10⁻⁷ ]

= 7.002

Therefore, the pH of 1.0 x 10⁻³ M of solution is 7.002.

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Fire extinguisher is used to stop fires in a laboratory.

Chemical splashes on to your face then we should go to eye wash station for washing face.

Bunsen burner is knocked over while lit and a large fire is started then we should use fire extinguisher and should come out of lab.

Carbon dioxide in fire extinguisher is more denser than oxygen so when we spray carbon dioxide on fire, it cut off the contact with oxygen and fire goes off.

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Answer: 5.44 x 10^24

Explanation:

Converting between molecules and moles is done by either multiplying by or dividing by Avogadro's number:

1-To go from moles to molecules, multiply the number of moles

by 6.022 x 10^23.

2-To go from molecules to moles, divide the numbers of molecules

by 6.022 x 10^23.

Given number of moles (9.04) We can compensate directly using the formula (Moles equal number of atoms/molecules over Avogadro's number)

Number of molecules = 9.04 x 6.022 x 10^23= 54.43888 x 10^23

now applying significant figure rules the answer is rounded to 3 digits and wrote in scientific notation making the final answer 5.44 x 10^24

Answer:

oxygen<carbon<aluminium<potassium

Explanation:

atomic radius increases down the group but decreases across the period

The functional group that is expected to be present in the final product between 1-hexyne and mixture of mercuric sulfate and aqueous sulfuric acid is Ketone.

In organic chemistry, ketone is a functional group with the structure R–C–R', where R and R' can be various carbon-containing substituents. Ketones contain a carbonyl group –C– and the  simplest ketone is acetone, with the formula CH₃CCH₃.

The reaction between 1-hexyne and mercuric sulphate in the presence of aqueous Sulphuric acid is a reaction that forms a product containing a carbonyl group.

The reaction occurs in alkynes but product formed depends on the structure of the alkyne. An aldehyde or ketone can be formed depending on the structure of the alkyne.

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Note: The question given on the portal is incomplete. Here is the complete question.

Question: What functional group would be expected to be found in the major, and final, organic product upon completion of the reaction between 1-hexyne and a mixture of mercuric sulfate and aqueous sulfuric acid?

Although the pKa constant is 4.8 and is a more straightforward expression, the Ka constant for acetic acid (CH3COOH) is 0.0000158 (= 10-4.8). Additionally, the strength of the acid increases with decreasing pKa values.

For instance, lactic acid has a pKa value of roughly 3.8, which indicates that it is a stronger acid than acetic acid.

Acetic acid, officially known as ethanoic acid, is an organic substance with the chemical formula CH3COOH that is acidic, colorless, and liquid (also written as CH3CO2H, C2H4O2, or HC2H3O2). Apart from water and other trace ingredients, vinegar has at least 4% acetic acid by volume, making acetic acid its primary ingredient.

The second-simplest carboxylic acid is acetic acid (after formic acid). It serves as a significant industrial chemical and reagent in the manufacture of cellulose acetate.

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Answer:

Mineral elements provide the color in fireworks. Barium produces bright greens; strontium yields deep reds; copper produces blues; and sodium yields yellow.

Explanation:

I hope my answer helped you! If you need more information or help, comment down below and I will be sure to respond if I am online. Have a wonderful rest of your day!

The values of entropy δs for the water, the surroundings, and the universe for the evaporation of water are positive, negative, positive.

What is entropy?

Entropy is a term used to describe the increase in disorganization inside a system or the assessment of the degree of unpredictability. It is denoted by  δs.

Gases have a higher entropy than liquids, which in turn has a higher entropy than solids. The entropy of water increases when it transforms from a liquid to a gas.

So, δs of water is positive.

The environment's entropy must decrease in order to provide the system with the thermal energy it needs.

So, δs of surroundings is negative.

The Second Law of Thermodynamics states that if a process is spontaneous i.e. water evaporation in universe.

So, δs of evaporation from open pan is positive.

The values of δs for the water, the surroundings, and the universe for the evaporation of water are positive, negative, positive.

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Answer:

To find the number of milligrams (mg) in 0.750 moles of zinc, you will need to know the atomic weight of zinc. The atomic weight of zinc is 65.38 g/mol.

To convert from moles to milligrams, you will need to multiply the number of moles by the atomic weight of zinc and then multiply by 1000 to convert the weight to milligrams.

Thus, the number of milligrams in 0.750 moles of zinc is:

0.750 moles * 65.38 g/mol * 1000 mg/g = 48.7850 mg

So there are approximately 48.79 mg of zinc in 0.750 moles of the element.

Explanation:

The Answer is d. half a trillion tons

What is fossil fuels?

Fossil fuel is a term for non-renewable energy sources such as coal, crude oil, coal products, derived gas, natural gas, petroleum products and non-renewable wastes. These fuels originate from plants and animals that existed in the geological past (millions of years ago).

When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the atmosphere. Greenhouse gases trap heat in the atmosphere, causing global warming.

I suppose the question is :

How much carbon dioxide have we emitted into the atmosphere by burning fossil fuels since the industrial revolution?

a- a million tons

b- a billion tons

c- half a billion tons

d- half a trillion tons

e- a trillion tons

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Isopentyl acetate is found in organic layer.

In this procedure, the organic product is isolated from inorganic substances. The organic product will be soluble in an organic solvent (organic layer) while the inorganic substances will be soluble in water (aqueous layer).

Solvents with significant dipole moments, the ability to separate charges, and the capacity to dissolve ions and other polar compounds are known as polar solvents. They comprise bonds between elements like oxygen and hydrogen that have widely varied electronegativities.

Non-polar solvents are defined as solvents that are made up of atoms with marginally different electronegativities. They have bonds between elements like carbon and hydrogen that have similar electronegativities. bonds with other atoms. Bonds between atoms with similar electronegativities will lack partial charges.

due to presence of large alkyl chain in isopentyl acetate

isopentyl acetate acts as a non polar compound , so its readily soluble in organic solvents rather then polar aqueous solvent

so isopentyl acetate is found in organic layer.

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A solution is prepared by dissolving 23. 7 g of cacl2 in 375 g of water. The density of the resulting solution is 1. 05 g/ml. The concentration of cacl2 is 0.5623 % by mass.

What is density?

How closely a material is packed together is determined by its density. The mass per unit volume is how it is formally defined. Symbol for density: D or Formula for Density: Where is the density, m is the object's mass, and V is its volume, the equation is: = m/V.

The density of a substance is a measurement of how tightly or loosely it is confined within a specific volume. We can travel through low-density materials like air, which has a density significantly lower than that of human tissue. Granite is a different material altogether. Never attempt to traverse stone.

Therefore, A solution is prepared by dissolving 23. 7 g of cacl2 in 375 g of water. The density of the resulting solution is 1. 05 g/ml. The concentration of cacl2 is 0.5623 % by mass.

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The number of moles of hydrogen peroxide is  0.402 moles

Calculation:

Water volume, V = 20.1 mL.

MnO4 has a molarity of 0.020 M.

the quantity of potassium permanganate solution in moles.

Solution:

Molarity is determined by:

M = Volume in liters/Numbers of moles

0.020=n/20.1

n=0.020×20.1

n=0.402moles

As a result, 0.402 moles of potassium permanganate solution are present.

6.02214076 x 1023 of any chemical unit, such as atom, molecules, ions, and others, constitute a mole. Due to the large number of atoms, molecules, or other components that make up any substance, the mole is a useful measure to utilize.

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The volume of the gas at 321 K would be 2.69 Litres, if the volume of gas at 298 K is 2.5 L

Since the pressure depends on the number of moles, it will remain constant and rest of formula is

[tex]\frac{Volume_{Intial} }{temperature_{inital}}[/tex] = [tex]\frac{Volume_{Final} }{temperature_{final} }[/tex]

which on cross multiplying becomes :

Volume(f) = (Volume(i) X temperature(f)) / temperature(i)

Volume = (2.5 * 321) / 298 = 2.69 Liters

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After assembling a gravity filtration apparatus, begin the separation of a mixture by [DECANTING ] it into the filter paper.

What are the steps?

After assembling a gravity filtration apparatus, begin the separation of a mixture by [DECANTING ] it into the filter paper. Pour the entire contents of the mixture into the filter paper, [  STIRRING ]  the solid in the filter paper if needed to speed up the filtration. After all the liquid has drained through the filter paper, finish by rinsing the solid with [  SOLVENT  ]

After a mixture has been poured through filter paper, the [ SOLID ] component remains on top while the [ LIQUID ] flows through. To collect the solid, spread the filter paper [ ON A WATCH GLASS ] and allow the solvent to  [ EVAPORATE ].

Once the vacuum filtration set-up is complete, start by  [ ADDING A SMALL AMOUNT OF WATER ] in the filter funnel. then, [ SLOWLY DECANT ] the mixture [ INTO THE MIDDLE OF THE FILTER PAPER ]

Thus, After assembling a gravity filtration apparatus, begin the separation of a mixture by [DECANTING ] it into the filter paper.

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By deducting the mass of the cup and water from the combined mass of the cup, water, and ice cubes, you may find the mass of the ice cubes. The mass of the ice cubes would be 110.4 g - 103.4 g = 7.0 g if the cup, water, and ice collectively weighed 110.4 g.

Both no particles are lost and no particles are gained. Additionally, the particles' size and shape do not alter. As a result, during phase change, matter and mass (or weight) are conserved (remain the same).

Energy gained by the ice equals the sum of the energy lost by the thermometer and the water. Using a polystyrene container in place of a copper container.

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Answer:

tangol is Ca Li -56-(99)

The quantity of heat (in kj) required to boil 945.1 g of water is 2134.30 KJ

Enthalpy of vaporization is theamount of heat required to evaporate the one mole of liquid under constant temperature and pressure. It is also called heat of vaporization.

Δ[tex]H_{vap}[/tex](enthalpy of vaporization of H2o)=40.7 KJ/mol

moles of H2o=945.1 gm

moles of H2o=mass/molar mass

                    =945.1gm/18.02 gm/mol

                     =52.44 mol

Δ[tex]H'_{vap}[/tex] to boil 426.1 of H2O= Δ[tex]H_{vap}[/tex]*no. of moles

                                          = 40.7 KJ/mol*52.44 mol

                                          = 2134.30 KJ

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