Can someone help please!

If a student used a pen to mark the baseline on the chromatography paper, it could affect the results of the experiment.

Chromatography is a laboratory technique used to separate and identify the components of a mixture based on their properties, such as solubility and molecular weight. In paper chromatography, a small amount of the mixture to be analyzed is placed on a strip of filter paper, and the paper is then placed in a solvent.

As the solvent moves up the paper, it carries the different components of the mixture with it, separating them based on their properties.

The baseline is a line drawn near the bottom of the paper that marks the starting point of the experiment. If a pen is used to mark the baseline, it can interfere with the separation of the components of the mixture by interacting with the solvent or the components themselves. This can result in inaccurate or unreliable results, which can impact the conclusions drawn from the experiment. Therefore, it's important to use a pencil or other non-reactive material to mark the baseline on chromatography paper.

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Answer:

Calcium chloride does not have a covalent bond , it is an ionic bond (which means donation of electrons takes place ). The charge of calcium ions is +2, while the charge of sodium ions is -1. The molecule of calcium chloride contains one calcium ion (+2) and two chloride ions (-1), resulting in an overall charge of 0, or neutral.

IONIC BONDING IN CALCIUM CHLORIDE \((CaCl_2)\)

Electron sharing produces covalent compounds, while electron donation produces ionic compounds. \(CaCl_2\) is a salt with an ionic bond. This is because calcium takes up an electron to each of the chlorine atoms, resulting in \(Ca^2^+\)ions for calcium and\(Cl^-\) ions for chlorine. At room temperature, it behaves like a normal ionic halide and is solid. Calcium is a metal with a non-metal sulphate bond.

Thus , Calcium chloride have ionic bonds present on them . No covalent bonds takes place in calcium chloride.

All of the given ions (acetate, hydroxide, and copper(II)) are present in the complete ionic equation. In the given precipitation reaction, barium hydroxide(aq) and copper (II) acetate(aq) react to form a precipitate of barium acetate(s) and a soluble product, copper (II) hydroxide(aq).

The complete ionic equation for the reaction would show all the aqueous ions dissociated in the solution. However, since barium acetate is insoluble in water, it will not dissociate into its constituent ions. Therefore, the ion that would not be present in the complete ionic equation is the acetate ion. The other ions, including acetate ion, hydroxide ion, and copper (II) ion, will be present in the complete ionic equation.
The precipitation reaction between barium hydroxide (Ba(OH)2) and copper(II) acetate (Cu(C2H3O2)2) can be represented as:

Ba(OH)2(aq) + Cu(C2H3O2)2(aq) → Ba(C2H3O2)2(s) + Cu(OH)2(s)

In the complete ionic equation, only soluble compounds are separated into ions:

Ba²⁺(aq) + 2OH⁻(aq) + Cu²⁺(aq) + 2C2H3O2⁻(aq) → Ba(C2H3O2)2(s) + Cu(OH)2(s)

Since both Ba(C2H3O2)2 and Cu(OH)2 are insoluble, they are not dissociated into ions. Thus, all of the given ions (acetate, hydroxide, and copper(II)) are present in the complete ionic equation.

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Answer: 144 inches

Explanation: 4 yards is 12 feet, so multiply 12 inches by 12 feet and you get 144 inches

Answer:

When Darrell is radioed back he would be asked to  “Go for it!”

Explanation:

Here we are given the fuel as C₅H₁₂, therefore the combustion reaction is given as

C₅H₁₂ + 8O₂ → 5CO₂ + H₂O

Mass of oxygen consumed on each lap = 300 g

Molar mass of oxygen gas O₂ = 32 g/mol

Number of moles of oxygen n 300 g of O₂ =

(300 g)/(32 g/mol) = 9.375 moles

For complete combustion, one mole of oxygen gas reacts with one mole C₅H₁₂, to form 5 moles of CO₂ and one mole of H₂O

Therefore 9.375 moles of oxygen ill combine with 9.375/8 or 1.172 moles of C₅H₁₂

Mass of 1.172 moles is given as

Mass = Number of moles × Molar mass

= 1.172 moles × 72.15 g/mole = 84.551 g

Therefore the mass of fuel to complete one lap = 84.551 g

However there are 25 gallons or 3.5 kg in the tank therefore we have

Number of laps the fuel in the tank can last  = Mass of fuel in the tank/ Mass of fuel consumed per lap

= 3.5/84.551 = 41.395 laps.

Number of laps the fuel in the tank can last  = 41.395 laps.

Since there are 20 laps left to complete, which is less than 41.395 laps left in the fuel tank of the vehicle, then Darrell would be asked to go for it.

The relative abundance of isotopes is the number of atoms of a particular isotope divide by the total number of atoms of all isotopes of that element, multiplied 100 percent.

The relative abundance of an isotope is the percentage of atoms with a specific atomic mass found in a naturally occurring sample of an element.

Also relative abundances refers to the relative proportions of the stable isotopes of each element. They are most often quoted as atom percentages

To calculate the percent abundance of each isotope in a sample of an element,  the number of atoms of a particular isotope is usually divide by the total number of atoms of all isotopes of that element and then multiply the result by 100 since it is expressed in percentage.

Mathematically, the formula for relative abundance is given as;

R.A = ( number of atoms of isotope / total number of atoms ) x 100%

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Answer:

Buffers can be made from weak acids or base and their salts.

Explanation:

hope this helps!

(if not tell me in the comments and i will try to help you!)

Answer:

Buffers are made by adding a strong acid or base to a weak acid or base.

Explanation:

Answer:

Pressure initially is 760 torr.

Temperature is at 273.15

Temperature is increased to 298.15

Pressure increases by a factor of 298.15 / 273.15 = 1.0915248032

760 * 1.0915248032  = 829.558850432  torr

Explanation:

Answer:

D.) The nuclear model describes the atom as a dense, positive nucleus surrounded by a cloud of negative electrons.

Answer

The nuclear model describes the atom as a dense, positive nucleus surrounded by a cloud of negative electrons.

The percent change in volume is 21 %.

given that :

temperature , T1 = 273 -28 = 245 K

temperature , T2 = 273 + 9 = 282 K

pressure P1 = P

pressure P2 = P - O.O5 P = 0.95 P

Volume V1 = V

volume V2 = ?

using ideal gas equation , we get :

P1 V1 / T1 = P2 V2 / T2

V2 = (P1 V1 T2 ) / P2 T1

V2 = ( P × V × 282 ) / ( 0.95 P × 245 P )

V2 = 1.211 V

change in volume is given as = V2 - V1

                                                 =  1.211 V - V

                                                 = 0.211 V

Percent change in volume is = (0.21 V)) / V ) × 100 %

                                                 = 21 %

Thus, For many purposes we can treat propane C3H8 as an ideal gas at temperatures above its boiling point of −42.°C Suppose the temperature of a sample of propane gas is raised from -28.0°C to 9.0°C, and at the same time the pressure is increased by 5.0% . the percent change in volume in 21 %.

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The conjugate base of an acid does not always carry a negative charge. To understand this, let us first define the terms 'acid' and 'conjugate base'.An acid is a substance that releases H+ ions when dissolved in water.

An example of an acid is hydrochloric acid (HCl) which releases H+ ions and chloride ions (Cl-) when dissolved in water. HCl + H2O → H3O+ + Cl-.A conjugate base is the substance that is formed when an acid loses a proton (H+ ion). It can be formed from any acid, whether it is weak or strong. The conjugate base of an acid is the species that remains after an acid has donated a proton to another species. In the case of HCl, Cl- is the conjugate base, and it carries a negative charge because it has gained an electron and has a greater number of electrons than protons.Conversely, the conjugate base of a weak acid may not carry a negative charge. For example, the conjugate base of acetic acid (CH3COOH) is acetate ion (CH3COO-) which does not carry a negative charge. Acetate ion has a greater number of electrons than protons, but its net charge is zero. Thus, the conjugate base of an acid does not always carry a negative charge.

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Answer:

boron sulfide

b=boron

s=sulfer

Explanation:

For a low-pressure center to be maintained or strengthened, the surface convergence must be balanced by cyclones aloft. This is because cyclones are areas of low barometric pressure, which create upward motion and can enhance the low-pressure system at the surface.

This process is known as positive feedback and can lead to the development of stronger and more intense low-pressure systems.
For a low-pressure center to be maintained or strengthened, the surface convergence must be balanced by "divergence" aloft. Here's an explanation: low-pressure centers, or cyclones, are characterized by converging air at the surface. This convergence forces air to rise.

As it rises, it cools, leading to condensation and cloud formation. In order to maintain or strengthen the low-pressure system, the air that has risen needs to be transported away from the center, which is achieved through divergence aloft. This helps maintain the balance between the converging air at the surface and the diverging air aloft, ensuring that the low-pressure system can persist or intensify.

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The mass of the balls will determine the magnitude of force applied on the balls. They will also move in thesame direction

Newton second law of motion states that the rate of change of momentum is directly proportional to the applied force. This law actually gives the operational definition of force.

From the law,

F= km(v-u)/t

where k = 1

f = m(v-u)/t

recall that (v-u)/t = a,

a is the acceleration

therefore F = ma

where m is the mass of the object.

Therefore the force applied on each ball will depend on the mass of each ball. The direction of the movement in of the ball will be thesame if they are both kicked in thesame direction.

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Answer:

The electronic configuration of ions formed are:

Li+ (2) => 1s2

Cl- (18) => 1s2 2s2 2p6 3s2 3p6

Explanation:

Lithium metal, Li will lose 1 electron to lithium ion Li+. Chlorine atom, Cl will receive the 1 electron to form the chloride ion Cl- as shown by the following equation below:

Li —> Li+ + e

Cl+ e —> Cl-

Combine both equation

Li + Cl + e —> Li+ + Cl- + e

Cancel out 'e'

Li + Cl —> Li+ Cl-

Thus, we can write the electronic configuration for the reaction as follow:

Before reaction:

Li (3) => 1s2 2s1

Cl (17) => 1s2 2s2 2p6 3s2 3p5

After reaction

Li+ (2) => 1s2

Cl- (18) => 1s2 2s2 2p6 3s2 3p6

Therefore, the electronic configuration of the ions formed are:

Li+ (2) => 1s2

Cl- (18) => 1s2 2s2 2p6 3s2 3p6

Answer:

7.67

Explanation:

According to molar concentration, the molarity of solution which contains 22.41 grams of NaCl in 50.0 ml of solution is 7.67 M.

Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.

The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.

In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.Substitution of values in the given formula gives, molarity= 22.41/58.44×1/0.05=7.67 M.

Thus, the  molarity of solution which contains 22.41 grams of NaCl in 50.0 ml of solution is 7.67 M.

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Based on the observations described, it is likely that the white solid is a true hydrate.

Water droplets on the side of the test tube: When heating a hydrate, the water molecules trapped within the crystal lattice are released as vapor. The presence of water droplets on the side of the test tube indicates that water was indeed released during the heating process.

Brownish residue: The brownish residue obtained after heating the solid suggests that the white solid might contain a transition metal ion. Transition metal ions can form complex compounds that exhibit different colors, including brown.

Dissolving in water: The brownish residue dissolves in water, indicating that it is soluble in the solvent.

Dark reddish-brown solution: The solution obtained after dissolving the brownish residue is described as dark reddish-brown. This color could be attributed to the formation of a complex compound between the transition metal ion in the residue and the water or other substances present in the solution.

Based on the observations of water droplets upon heating, the brownish residue that dissolves in water, and the resulting dark reddish-brown solution, it is likely that the white solid is a true hydrate.

The presence of water droplets and the dissolution of the residue suggest that water was released from the solid during heating, indicating the presence of water molecules within the crystal lattice.

The color change to brownish and the subsequent dark reddish-brown solution point towards the involvement of a transition metal ion, possibly forming a complex compound.

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210 83 decays by releasing 1 y particle and 1 B particle and 1a to form the isotope this decay process is called alpha decay,

An atomic nucleus emits an alpha particle, which is made up of two protons and two neutrons, decreasing the atomic number by two and the atomic mass by four. In addition to the alpha particle, the decay also releases a y particle, which is a type of electromagnetic radiation, and a B particle, which is a high-speed electron. The resulting isotope, 206 81, has an atomic number of 81, which means it is the element thallium (Tl), it also has an atomic mass of 206, which is the sum of the protons and neutrons in the nucleus.

This type of decay is a natural process that occurs in some radioactive isotopes, where the nucleus becomes unstable and seeks to achieve a more stable state by releasing particles. Understanding these decay processes is important in fields such as nuclear physics and medicine, where radioactive isotopes are used for a variety of applications. So therefore the isotope formed after the decay of 210 83 releases a y particle, a B particle, and an alpha particle is 206 81, this decay process is called alpha decay,

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The relative molar quantities of the species in a 1 M solution of  \(\rm NH_3\)(aq) are: \(\rm H_2O > NH_3 > NH_4+ =OH^- > H_3O^+\).

Solution is defined as the homogenous mixture of solute and solvent in an aqueous medium.

i) Molar amount of \(\rm H_2O\) will be highest because it is the solvent (excess amount).

ii) \(\rm NH_3\) partly dissociate in water. The reaction is as follows:

\(\rm NH_3(aq) + H_2O(l) \leftrightarrow NH4^+(aq) + OH^-\)

\(\rm Ka =\dfrac { [NH_4^+][OH^-] }{ [NH_3] }= 1.80 \times 10^{-5 }\)

So, \(\rm [NH_3] > ([NH_4^+] = [OH^-]\)

iii) \(\rm H_3O^+\) would be least due to the production of \(\rm OH^-\) by the dissociation of \(\rm NH_3\).

Therefore, \(\rm H_2O > NH_3 > NH_4+ =OH^- > H_3O^+\) is the correct order based on relative molar quantities.

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The 1.04 pCi activity of 131I in cow's milk near nuclear reactors corresponds to a mass of approximately 8.49 x 10^-4 grams.

To calculate the mass of 131I with an activity of 1.04 pCi (picocuries) per liter, we need to convert the activity to the corresponding mass using the known relationship between radioactivity and mass.

The conversion factor for iodine-131 is approximately 1 Ci (curie) = 3.7 x 10^10 Bq (becquerel). Since 1 pCi = 0.01 nCi = 0.01 x 10^-9 Ci, we can convert the activity to curies:

1.04 pCi = 1.04 x 10^-12 Ci

To convert from curies to grams, we need to know the specific activity of iodine-131, which represents the radioactivity per unit mass. The specific activity of iodine-131 is approximately 4.9 x 10^10 Bq/g.

Using these values, we can calculate the mass of 131I:

(1.04 x 10^-12 Ci) * (3.7 x 10^10 Bq/Ci) * (1 g / 4.9 x 10^10 Bq) ≈ 8.49 x 10^-4 g

Therefore, the mass of 131I with an activity of 1.04 pCi per liter is approximately 8.49 x 10^-4 grams.

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Answer:

This question appears incomplete

Explanation:

However, it should be noted that addition of soluble salts generally lowers the freezing point of water hence after the addition, water will no longer freeze at 0°C but lower.

Soluble salts tend to form more ions in water, it is these ions that are responsible for interfering with the hydrogen bonds hence lowering the freezing. Thus, (since each bag are of the same weight) the bag that contains the salt that ionizes more in water will lower the freezing point by the greatest amount.

NOTE: Different weight of the salts could lead to more ions been formed in the water by some salts as against the other.

Answer:

a. 21.7824 g

b. 0.2362 g

c. 31.5273 g

Please see the answers in the picture attached below.

Explanation:

Please see the step-by-step solution in the picture attached below.

Hope this answer can help you. Have a nice day!

The mass of solute required in each case can be obtained form the stoichiometry of the reaction.

We know that the mass of each solution can be obtained from the relation;

mass/molar mass = concentration × volume

mass = concentration × volume × molar mass

a)

mass =  0.125 M  ×  1.00 L ×  174 g/mol = 21.75 g

b) mass = 0.015 M  × 375 /1000 × 42 g/mol = 0.24 g

c) mass = 0.350 M × 500/1000 × 180 g/mol =31.5 g

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Answer: A) NO increases the rate at which \(SO_3\) molecules are formed.

Explanation:

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more reactant molecules can cross the energy barrier by undergoing collisions and convert to products.

\(2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)\)

Thus NO will increase the rate of reaction by lowering the activation energy and thus the colllisions among \(SO_2\) and \(O_2\) molecules will incraese which in turn will lead to formatioon of more \(SO_3\) molecules.

Answer:

A) NO increases the rate at which  molecules are formed.

Explanation:

PLATO

The balanced ionic equation for this acid-base reaction is:

2OH-(aq) + H+(aq) + SO4 2-(aq) → 2H2O(l) + SO4 2-(aq)

In this equation, the hydroxide ions (OH-) from the CSOH react with the hydrogen ions (H+) from the H2SO4 to form water (H2O) molecules. The sulfate ions (SO4 2-) are spectator ions and do not participate in the reaction.
Hi! I'd be happy to help you write a balanced ionic equation for the given acid-base reaction. The reaction you provided is:

2CsOH(aq) + H2SO4(aq) → ?

First, let's balance the chemical equation:

2CsOH(aq) + H2SO4(aq) → Cs2SO4(aq) + 2H2O(l)

Now, we'll write the total ionic equation by breaking down the aqueous compounds into their respective ions:

2Cs⁺(aq) + 2OH⁻(aq) + 2H⁺(aq) + SO4²⁻(aq) → 2Cs⁺(aq) + SO4²⁻(aq) + 2H2O(l)

Finally, we'll write the net ionic equation by canceling out the spectator ions (Cs⁺ and SO4²⁻):

2OH⁻(aq) + 2H⁺(aq) → 2H2O(l)

And there you have it! The balanced ionic equation for the acid-base reaction is:

2OH⁻(aq) + 2H⁺(aq) → 2H2O(l)

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Answer:

(a)57.48 percent (b) 29.45 percent

Explanation:

copper(II) bromide is 29.45 percent copper and 71.54 percent bromine. so the first element percentage composition is always the percentage composition of the compound.

that goes same with sodium hydroxide. it  is 57.48 percent sodium, 40 percent oxygen, and 2.52 percent hydrogen.