In your own words, explain why a study published a cereal company that finds that breakfast is the most important meal of the day is likely to contain bias.

Answer:

Place 20.0 g NaOH(s) in a flask and dilute to 1.00 L with water.

Explanation:

1.66 M is the concentration of the chemist's working solution.

Molarity (M) is the amount of a substance in a certain volume of solution. Molarity is defined as the moles of a solute per litres of a solution. Molarity is also known as the molar concentration of a solution.

In this case, we have a solution of Zn(NO₃)₂.

The chemist wants to prepare a dilute solution of this reactant.

The stock solution of the nitrate has a concentration of 4.93 M, and he wants to prepare 620 mL of a more dilute concentration of the same solution. He adds 210 mL of the stock and completes it with water until it reaches 620 mL.

We want to know the concentration of this diluted solution.

As we are working with the same solution, we can assume that the moles of the stock solution will be conserved in the diluted solution so:

[tex]n_1[/tex]= [tex]n_2[/tex]  (1)

and we also know that:

n = M x [tex]V_2[/tex]

If we replace this expression in (1) we have:

[tex]M_1[/tex] x [tex]V_1[/tex]= [tex]M_2[/tex] x [tex]V_2[/tex]

Where 1, would be the stock solution and 2, the solution we want to prepare.

So, we already know the concentration and volume used of the stock solution and the desired volume of the diluted one, therefore, all we have to do is replace the given data in (2) and solve for the concentration which is [tex]M_2[/tex]:

4.93 x 210 =  620 x[tex]M_2[/tex]

[tex]M_2[/tex] = 1.66 M

This is the concentration of the solution prepared.

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Aluminum can be oxidized by [tex]Li^{+}[/tex] and [tex]Ca^{2+}[/tex]

Some of the metal corrodes (or oxidizes) and forms the corresponding metal oxide on the surface as a result of a chemical reaction between the metal surface and the oxygen in the air. The corrosion products that occur in some metals, like steel, are highly apparent and loose.

According to reactivity series (The array of metals in the descending order of their reactivities is referred to as the metals' reactivity series. It is sometimes referred to as the metals in the activity series.)

Lithium and calcium ions are more reactive than aluminum ion and they are less electronegative.

Since silver and tin are more electronegative than aluminum so, they cannot oxidize aluminum.

∴ [tex]Li^{+}[/tex] and [tex]Ca^{+2}[/tex] ions can oxidize aluminum.

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Answer:

1) mass and type of material

2) type of material

3) temperature

Explanation:

Answer:

For Ed

Explanation:

The first one is: The physical proprieties.

The second one is: The pH of the solution.

I've been seeing the same answers from above around though, so I may be wrong. But either way, I tried.

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Answer:

4.8 g H₂O

Explanation:

To find the mass of water, you need to (1) convert grams B₂H₆ to moles B₂H₆ (via molar mass from periodic table), then (2) convert moles B₂H₆ to moles H₂O (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles H₂O to grams H₂O (via molar mass from periodic table).

It is important to arrange the ratios/conversions in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 2 sig figs because the given value (3.7 grams) has 2 sig figs.

Molar Mass (B₂H₆): 2(10.811 g/mol) + 6(1.008 g/mol)

Molar Mass (B₂H₆): 27.67 g/mol

1 B₂H₆ + 3 O₂ ---> 2 HBO₂ + 2 H₂O
^                                             ^

Molar Mass (H₂O): 15.998 g/mol + 2(1.008 g/mol)

Molar Mass (H₂O): 18.014 g/mol

3.7 g B₂H₆          1 mole            2 moles H₂O           18.014 g
----------------  x  ---------------  x  -----------------------  x  -----------------  =  4.8 g H₂O
                          27.67 g           1 mole B₂H₆              1 mole

Energy levels inside an atom are the specific energies that electrons can have when energy occupies specific orbitals. Electrons can be excited to higher energy levels by absorbing energy from the surroundings, an equivalent light is emitted when an electron returns from a high energy state to a lower one. Representation of this diagrammatic is known as the energy level diagram.

Answer:

95.45 moles

Explanation:

CO2 has mole weight  12 + 2 *16 = 44 gm/mole

4200 gm / 44 gm/mole = 95.45 moles

Answer:

c.

Explanation:

gravitational potential energy describes the amount of energy something could have based off of the amount of gravity acting on the object. so energy stored in height difference would be the best answer because gravity is acting on those objec6s

If data from a clinical trial contains personal information about a study participant, De-identification process should be used to separate identifying information from health information. Thus, Option (A) is correct

De-identification is a process of detecting identifiers (e.g., personal names and social security numbers) that directly or indirectly point to a person (or entity) and deleting those identifiers from the data.

De-identification and anonymization are strategies that are used to remove patient identifiers in electronic health record (EHR) data.

Hence, De-identification process should be used to separate identifying information from health information. Thus, Option (A) is correct.

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Answer:

Explanation:Hyaluronic acid is a natural substance found in the fluids in the eyes and joints. It acts as a cushion and lubricant in the joints and other tissues.

Different forms of hyaluronic acid are used for cosmetic purposes. Hyaluronic acid might also affect the way the body responds to injury and help to decrease swelling.

Hyaluronic acid injections are US FDA-approved for several conditions, including cataracts, osteoarthritis, and as an injectable gel filler (Juvedérm) for facial wrinkles. People also commonly take hyaluronic acid by mouth and apply it to the skin for UTIs, acid reflux, dry eyes, wound healing, aging skin, and many other conditions, but there is no good scientific evidence to support most of these other uses.

How does it work ?

Uses & Effectiveness ?

Likely Effective for

Cataracts. Injecting hyaluronic acid into the eye is effective when used during cataract surgery by an eye surgeon.

Swelling (inflammation) and sores inside the mouth (oral mucositis). Applying an FDA-approved hyaluronic acid gel is effective for treating mouth sores. It's not clear if other products help.

Answer:

Explanation:

Hyaluronic acid is a natural substance found in the fluids in the eyes and joints. It acts as a cushion and lubricant in the joints and other tissues. Different forms of hyaluronic acid are used for cosmetic purposes. Hyaluronic acid might also affect the way the body responds to injury and help to decrease swelling.

(❛◡❛✿)!

Answer:

7.22 x 10¹⁰ ng Ni

Explanation:

To find the mass of nickel, you need to (1) convert moles to grams (via atomic mass from the periodic table) and then (2) convert grams to nanograms. These ratios need to be multiplied by each other, starting with the given value. It is important to arrange the conversions/ratios in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 3 sig figs to reflect the given value (1.23).

Atomic Mass (Ni): 58.693 g/mol

1 gram = 1 x 10⁹ nanograms

1.23 moles Ni             58.693 g               1 x 10⁹ ng
----------------------  x  ----------------------  x  ---------------------  =  7.22 x 10¹⁰ ng Ni
                                     1 mole                       1 g

Answer:

2311.2 cal

Explanation:

540 cal / g    *   4.28 g = 2311.2  cal

2311.2 cal heat is needed to change 4.28g of water to steam.

Heat is the transfer of kinetic energy from one medium or object to another, or from an energy source to a medium or object.

The heat of vaporization is defined as the amount of heat needed to turn 1g of a liquid into a vapour, without a rise in the temperature of the liquid.

The heat of vaporization is equal to the thermal energy required for vaporization divided by the mass of the substance that is vaporizing. Its formula is Hv = q/m.

Putting the values in the formula:

540 cal / g  x 4.28 g = 2311.2  cal

Hence,  2311.2 cal heat is needed to change 4.28g of water to steam.

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Answer:

8.33 atm

Explanation:

Xe is   5  out of (4+5)   or   5 / 9 ths of the gas present

  5/9  * 15 atm = 8.33 atm

Taking into account definition of percent yield, the percent yield for the reaction is 91.17%.

In first place, the balanced reaction is:

Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The following rule of three can be applied: if by reaction stoichiometry 159.7 grams of Fe₂O₃ form 111.7 grams of Fe, 50.5 grams of Fe₂O₃ form how much mass of Fe?

[tex]mass of Fe=\frac{50.5 grams of Fe_{2} O_{3} x111.7 grams of Fe}{159.7 grams of Fe_{2} O_{3}}[/tex]

mass of Fe= 35.32 grams

Then, 35.32 grams of Fe can be produced from 50.5 g iron(III) oxide.

The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.

The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:

[tex]percent yield=\frac{actual yield}{theorical yield}x100[/tex]

where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.

In this case, you know:

Replacing in the definition of percent yields:

[tex]percent yield=\frac{32.2grams}{35.32grams}x100[/tex]

Solving:

percent yield= 91.17%

Finally, the percent yield for the reaction is 91.17%.

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A complete ionic equation shows ions formed from each of the species. It also show the charge on each of the ions.It also shows all reactants as compounds or elements. The ions formed and their charges can only be inferred from this equation.

The net ionic equation shows  the chemical species involve in chemical reaction while the complete ionic equation also involve the spectator ions.

These ions are same in both side of chemical reaction and thus cancels out each other.

Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.  

The net ionic equation state that whether precipitation is occur or not.

If the chemical reaction have no net ionic equation it means all are in aqueous from not precipitation occur.

Balanced Chemical equation:

HClO₂(aq) + NaOH(aq) → H₂O(l) + NaClO₂ (aq)

Ionic equation:

H⁺(aq) + ClO₂⁻(aq) + Na⁺(aq) + OH⁻(aq) → H₂O(l) + Na⁺(aq) + ClO₂⁻ (aq)

Net ionic equation:

H⁺(aq) + OH⁻(aq) → H₂O(l)  

The ClO₂⁻(aq) and Na⁺ (aq) are spectator ions that's why these are not written in net ionic equation.

The water can not be splitted into ions because it is present in liquid form.

Hence, The net ionic equation shows  the chemical species involve in chemical reaction while the complete ionic equation also involve the spectator ions.

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Answer:

It appears all of them are correct
Smaller drops will scatter around while maintaining their shape
Larger drop will spread stick to the surface.
and drops close together will join to form on gigantic sphere(but not perfect sphere)
and if they are in the sun, they'll eventually evaporate

Explanation:

Answer:

36.3375 g

Explanation:

The force exerted between S and q is ___4 times____ the force exerted between S and p.

Coulomb's law states that , the electrostatic force of attraction or repulsion between two charged bodies is directly proportional to the product of the charges and is inversely proportional to the square of the distance between them

It is given by

[tex]\rm F = k_e \dfrac{q_1 q_2}{r^2}[/tex]

r is the distance between two bodies

It is given that

Charge q is 1 unit of distance away from the source charge S

Charge p is two times further away from the source charge S

force exerted between S and q

distance between the charges is 1 unit

[tex]\rm F_{qs} = k_e \dfrac{q_q q_s}{1^2}\\\\\rm F_{ps} = k_e \dfrac{q_p q_s}{2^2}\\[/tex]

The force exerted between S and q is _______ the force exerted between S and p.

[tex]\rm F_{qs} = k_e \dfrac{q_q q_s}{1^2} = F_{ps} = k_e \dfrac{q_p q_s}{2^2}\\\\[/tex]

Assuming the charges to be q units

Then

[tex]\rm F_{qs} = k_e \dfrac{q_q q_s}{1^2} = F_{ps} = k_e \dfrac{q_p q_s}{2^2}\\\\\\\\\dfrac {F_{qs}}{F_{ps}} = \dfrac{2^2}{1^2} = 4 \\\\\\{F_{qs}} = 4{F_{ps}}[/tex]

Therefore ,

The force exerted between S and q is ___4 times____ the force exerted between S and p.

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Answer:

T₂ = 39.4 °K

Explanation:

Because you are only dealing with volume and temperature, you can use Charles' Law to find the missing value. The formula looks like this:

V₁ / T₁ = V₂ / T₂

In this formula, "V₁" and T₁" represent the initial volume and temperature. "V₂" and "T₂" represent the final volume and temperature. You have been given values for all of the variables except for "T₂". Therefore, by plugging these values into the formula, you can simplify to find the answer.

V₁ = 350 mL                     T₁ = 45 °K

V₂ = 400 mL                     T₂ = ?

V₁ / T₁ = V₂ / T₂                                        <----- Charles' Law formula

(350 mL)(45 °K) = (400 mL)T₂                <----- Insert values into variables

15750 = (400 mL)T₂                                <----- Multiply left side

39.4 = T₂                                                 <----- Divide both sides by 400

Answer:

Sulfur dioxide (SO2)

⇒ Why is this the best option?

To determine the polarity of the molecule, there are two requirements. The first one has a variety of terminal atoms, whereas the second has a lone pair on the center atoms. The molecule is polar if one of the requirements is met; else, it is nonpolar. The oxygen atom is a terminal atom because it surrounds the sulfur atom, which is the center element in the SO2 molecule's Lewis structure. In this molecule, there are two terminal oxygen atoms. If we look at the first criterion, we can see that it is not met because it calls for the presence of two separate terminal atoms.

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Answer:

can you post a photo? to help y with the question

Explanation:

The pH can be obtained directly from the concentration using the formula below pH = - log [H⁺]  Hence, pH of a 8.4x10⁻⁶ M H⁺ solution is 5.08.

A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid and higher values more alkaline.

Taking the negative logarithm of the concentration of hydronium ions that are in the solution:

pH = - log [H⁺]

     = - log [8.4x10⁻⁶ ]

     =  5.08

Hence, pH of a 8.4x10⁻⁶ M H⁺ solution is 5.08.

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Answer:

299.83°K

Explanation:

So, kelvin is a means of measuring temperature, as the question implies. To convert Celsius, one form of measuring temperature, to Kelvin, another form of measuring temperature, we must know the conversion median. Our median is that 0°C = 273.15°K. So, now, as we know that 0°C = 273.15°K, 26.68°C = 273.15°K + 26.68°. Because 273.15K might as well be zero degrees celsius (according to our median 0°C = 273.15°K), we simply add 26.68° to 273.15K and get 299.83°K

Answer:

C.) lowering the pressure

Explanation:

As you can see, the liquid and gas phases are stacked right on top of each other. Since temperature is on the x-axis, this means that these phases exist at the same temperature (disregarding any other variables). This means that changing the temperature would not change the liquid phase to the gas phase.

If we want to get the sample into the gas phase, we need to manipulate the sample based on the y-axis. To lower the sample into the gas phase, we need to lower the pressure, which is the variable on the y-axis. This will work because pressure decreases as you go down the y-axis.

Answer:

OC. Fe³+

Explanation:

Greater reduction potential (bigger positive E value) means that things wants to get electrons. For this, you have to look at the chart that I have attached. Since, Fe3+ has highest E value out of other options, it will likely be reduced.

The species which is most likely to get reduced is Fe³⁺.

Reduction is the process of the addition of electrons and loss of oxygen atoms. It is part of redox reactions.

Redox reactions are the type of reactions in which oxidation and reduction simultaneously take place. Oxidation is the addition of oxygen atoms. Reduction is the removal of oxygen atoms.

Redox reaction can be represented as:

PbO (s) + H₂ (g) → Pb(s) + H₂O (l)

In the above reaction, PbO is getting reduced and H₂ is getting oxidized.

Fe³⁺ is most likely to get reduced because the more positive the value of reduction potential, the more will be its tendency to get reduced.

In the given four species, the value of the reduction potential of Fe³⁺ is the highest.

Values of the reduction potential of four species are:

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Answer:

0.004136 moles

Explanation:

From our question we have been asked to determine the quantity in moles of silver atoms having 2.49 × 10²¹ atoms of silver.

We know that from Avogadro's constant, one mole of silver contains 6.02 x 10²³ atoms.

Thus,

1 mole of silver contains 6.02 x 10²³ atoms.

x moles of silver contains 2.49 × 10²¹ atoms

Cross multiply to obtain the number of moles of silver,

x moles = (2.49 × 10²¹ x 1)/(6.02 x 10²³)

= 0.004136 moles

Therefore the quantity of silver in moles is 0.004136 moles

A chemical equilibrium when the amounts of reactants or products no longer change.

Explanation:

Chemical equilibrium is a dynamic process, meaning the rate of formation of products by the forward reaction is equal to the rate at which the products re-form reactants by the reverse reaction.

Answer:

The balanced chemical equation is P₄ (s) + 5O₂ (g) → P₄O₁₀ (s)

Explanation:

In order to balance the chemical equation, you first need to see what's out of balance.

In this case our Oxygen is not balanced, so in order to make the two the same, we need to see what coefficient we need to add to the compounds to balance the problem.

So, adding a coefficient of 5 to  the O₂ will result in an equal number of oxygen on both sides.

The balanced nuclear equation for the β emission of the following isotopes is seen below:

92                 92                0

Sr            ⇒ Y         +   e

38                  39             -1

This is also known as beta decay in which a beta ray is emitted from an atomic nucleus.

The element formed during the beta emission of strontium is referred to as Yttrium.

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