Which of these is a balanced chemical equation?

Hello  Bobby792003

The best way to get rid of a marker stain on your skin is rubbing alcohol.

:)

A mixture of charcoal, sand, sugar, and water is a heterogeneous mixture. Sugar can easily dissolve in water. Slightly heating the mixture will ensure all of the sugar is dissolved in the water. The mixture then can be filtered to separate out sugar solution from sand and charcoal. The mixture of sand and charcoal is washed several times with water and filtered so that no traces of sugar solution remain in the mixture. To the mixture containing sand and charcoal, water is added. Charcoal being lighter floats on the surface of water, whereas sand being heavy sinks to the bottom. The charcoal floating can be removed manually. After all the charcoal is removed, the mixture of sand and water is again filtered and the sand collected on filter paper is dried. Therefore, by using the above process sand can be separated out from a mixture of charcoal, sand, sugar, and water.

The process of separating sand from a mixture of charcoal, sand, sugar, and water involves sedimentation, decantation, filtration, and evaporation. Sedimentation and decantation help in separating sand and charcoal from sugar and water, filtration further separates sand and charcoal, and the remaining sugar and water can be separated through evaporation.

To separate sand from a mixture of charcoal, sand, sugar, and water, you can apply the process of filtration, sedimentation, and evaporation. First, sedimentation and decantation could be used to separate the sand and charcoal from the sugar and water. Given that sand and charcoal are insoluble, they will settle at the bottom of the container after some time, which can then be separated by gently pouring out the water and sugar solution. Then, you could proceed to use filtration to separate the charcoal and the sand. Due to their differences in size, the sand will be caught in the filter, while the charcoal will pass through. Lastly, the evaporation method can be used to separate the sugar from the water. When the mixture is heated, the water will evaporate, leaving the sugar behind.

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The density of crystal is 2.65 g / mL

we know that

Density = Mass / Volume

So volume occupied = Mass / density

Mass of crystal = 4.46 g

So volume occupied by crystal = 4.46 / 2.65 = 1.68 mL

As the graduated cylinder contains water upto 25.0 mL

So if we immerse the crystal in that cylinder the water level will rise to 25+1.68 = 26.68mL

so the new read will be 26. 68 mL

To calculate the volume of the unknown crystal, subtract the initial volume of water from the final volume, assuming the crystal is insoluble. Use the formula: Volume of Crystal = Final Volume - Initial Volume (water). Substitute the given values to find the volume of the crystal.

The volume of the unknown crystal can be calculated using the given density and the mass of the sample added to the graduated cylinder.

First, we need to calculate the volume of water in the graduated cylinder by subtracting the initial volume (25.0 ml) from the final volume. Assuming the unknown crystal is insoluble in water, the total volume will be the sum of the water volume and the volume of the crystal.

The final volume can be calculated using the formula:

Final Volume = Initial Volume (water) + Volume of Crystal

By rearranging the formula, we can solve for the volume of the crystal

Volume of Crystal = Final Volume - Initial Volume (water)

Substituting the given values, the volume of the crystal can be calculated.

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all of above ! they are involved in all thee mentioned here

The answer is B. 6CO2+H2O yields C6H12O6+ 6H20.

The molar concentration of the solution is 1.55 mol/L.

1. Convert grams to moles.

[tex]\text{Moles of NaOH} = 15.5 \text{g NaOH} \times \frac{\text{1 mol NaOH}}{\text{40.00 g NaOH}} = \text{0.3875 mol NaOH}\\[/tex]

2. Convert millilitres to litres

[tex]V = 250.0 \text{mL} \times \frac{\text{1 L}}{\text{1000 mL}} = \text{0.2500 L}\\[/tex]

3. Calculate the molar concentration (c)

[tex]c = \frac{\text{moles}}{\text{litres}} = \frac{\text{0.2875 mol}}{\text{0.2500 L}} = \textbf{1.55 mol/L}[/tex]

Molarity of solution is 1.5501

Given data:

Molarity of NaOH = ?

Volume of solution = 250 ml

Mass of solute = 15.5 grams

Solution:

Formula:

Molarity = Mass of solute/Molar mass of solute * 1/volume of solution in liters.

First convert volume into Liters = 250/1000 =0.25 L

Now put the values in formula:

Molarity of NaOH = 15.5/39.997 * 1/0.25

                              = 1.5501

                                         Molarity of NaOH      =  1.55011

Answer: In a reversible reaction, the forward reaction takes place simultaneously the reverse reaction. Such a reaction, on reaching equilibrium, will have equal rate of going forward and going backward.

Explanation: It is a reaction in which the reactants reacts to give products and products reacts to give the reactants back simultaneously.

                     [tex]A+B\rightleftharpoons C+D[/tex]

In the above reaction reactants A and B reacts together to give products C and D, and vice versa.

In these reaction rate of reaction going forward is equal the rate of reaction going backward at the equilibrium.

In reversible reactions, the forward and backward reactions occur simultaneously, leading to a state of equilibrium. Changes to the system will shift this equilibrium in an effort to restore balance. The state of equilibrium can be quantitatively measured using an equilibrium constant, K.

In a reversible reaction, the forward reaction takes place simultaneously with the reverse reaction. At any time, these two processes occur at equal rates, leading to a state known as chemical equilibrium. This balance doesn't imply equal concentrations of the reactants and products but rather equilibrium in their reaction rates.

At equilibrium, changes in the system, such as introducing more reactants or removing products, will shift the equilibrium to re-establish the balance. For instance, if some product is removed, the system will favor the forward reaction to replace it, shifting the equilibrium right to restore equality in the reaction rates. This phenomenon is based on the principle of Le Chatelier.

Also noteworthy is that equilibrium constants, represented by K, are a quantitative measurement of a reaction's equilibrium state. They're defined through a mathematical function known as the reaction quotient, Q, which becomes the K constant when the system reaches equilibrium.

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Given data:

1 kilogram = 1,000 grams

how many kilograms is 1,216 grams?

Solution:

1000 grams = 1 kilogram

1 gram = 1/1000 kilograms

1216 grams = 1/1000 * 1216 = 1.216 kilograms.

                                                    Hence 1216 grams =  1.216 kilograms.

Answer:

B.6

Explanation:

Out of the 25 elements found in living things, 19 of them can be found in some organisms but not all.

There are 25 elements that living things on Earth need to survive. Out of all these 25 however, only 6 are needed by all living organisms universally. They include:

In conclusion, this means that 19 elements can be found in some living things but not all of them while 6 can be found in all of them.

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The correct option is;

c. by observing and measuring

Scientists are like detectives. They investigate or look for answers using organized steps;

     They carried out investigations under controlled conditions to ensure the   accuracy of their experiment.

Final answer:

In Peter's experiment, the independent variable is the temperature of the water, and the dependent variable is the amount of salt that dissolves. The independent variable is what the experimenter changes, and the dependent variable is what is measured in response.

Explanation:

Understanding Variables in an Experiment

In Peter's experiment to determine how much salt will dissolve in water as the temperature is increased, the independent variable is the temperature of the water, which Peter is controlling or changing. The dependent variable is the amount of salt that dissolves in the water, which will change in response to the temperature alterations. It's important not to confuse the independent and dependent variables as one is the cause (independent) and the other is the effect (dependent).

Example from Another Experiment

In the provided example where a scientist is observing bacteria growth on different gels, the independent variable would be the type of gel (A or B) since this is what the scientist has changed. The dependent variable would be the amount of bacteria growth observed after 24 hours, as this is the outcome that depends on the type of gel used.

The first ionization energy decreases from top to bottom within a group, as valence electrons are further away from the nucleus and more shielded by inner electrons. The correct statement is: The first ionization energy decreases from top to bottom within a group.

The first ionization energy typically follows a clear pattern within a group on the periodic table. According to the periodic trend in ionization energy, the first ionization energy decreases from top to bottom within a group.

This decrease occurs because, as you move down a group, valence electrons are further away from the nucleus and thus experience less pull. This reduced attraction makes it easier to remove an electron, resulting in lower ionization energies.

For instance, this can be seen in Group 1 alkali metals, where the outermost electron experiences lower effective nuclear charge due to increased electron shielding from inner filled shells.

The effect of temperature depends upon the extent of rise in temperature (for solids)

However in general if we increase temperature of a substance there will be increase in kinetic energy of the molecules and generally the volume of substance will increase

However there will be no effect on the mass of the substance due to increase / decrease in temperature

Density = mass / volume

As mass will remain constant and volume will increase with temperature the density of solid will generally decrease (very less though)

Final answer:

When the temperature of a solid increases, its volume increases, mass remains constant, and density decreases due to the expansion of the solid's material without a change in mass.

Explanation:

As the temperature of most solids increases, their volume typically increases due to the expansion in all three dimensions, as the kinetic energy of the atoms and molecules increases. However, the mass of the solid remains constant, because temperature change does not create or destroy matter in a closed system. Consequently, as the volume increases and mass remains the same, the density of the solid decreases. An example of this is how ice is less dense than liquid water, which is why ice floats. On the other hand, materials like corn syrup, which have a higher density than water, will sink when placed in water.

The density of mercury molecule is higher than water.

Density is defined as mass per unit volume.In other words, density is the amount of matter within a given amount of space. water has the density of 1.0 gram per milliliter whereas the mercury has a density of 13.6 grams per centimeter squared.

One reason for the differences in density between mercury and water is that the atomic mass of mercury is 200.59 grams per mole. The atomic mass of water is 18.0 grams per mole. This is because mercury has a larger nucleus than hydrogen or water.

Additionally, there are strong inter-molecular forces (hydrogen bonds) between water molecules. hydrogen molecules do not stack upon one another as nicely as mercury atoms. Thus, there is additional empty spaces between the water molecules leading to its lower mass per volume(density)

The formula of pentaphosphorus tetraoxide is P₅O₄

As per the convention of naming chemical compounds - the Prefix names are used for naming covalent compounds.

The prefix 'penta' means '5', so we use 5 as subscript for P.

The prefix 'tetra' means '4', so we use 4 as subscript for O.

Therefore the formula of pentaphosphorus tetraoxide is P₅O₄

To solve this problem, we're going to have to use the equation: E=hv

This equation tells us that the energy of a particle of light (E), called a photon, is proportional to its frequency (v), by a constant factor (h). That constant (Planck's constant) we know to be 6.626 × 10^-34 J·s. So, we can plug in the frequency and Planck's constant to solve for the energy (E).

E=( 6.626 × 10^-34 J·s)(7.29 × 10^14 hz)

E= 4.830354 × 10^-19

Round to 3 significant figures, and you're done!

E= 4.83 × 10^-19

Answer:

[tex]4.83\times 10^{-19} J[/tex] is the energy of exactly one photon of this light.

Explanation:

Frequency of the blue shade light = [tex]\nu =7.29\times 10^{14} Hz[/tex]

Energy of the photon is given by Planck's equation = E

[tex]E=h\nu[/tex]

h = Planck's constant = [tex]6.634\times 10^{-34} Js[/tex]

[tex]E=6.634\times 10^{-34} Js\times 7.29\times 10^{14} s^{-1}[/tex]

[tex]E=4.83\times 10^{-19} J[/tex]

[tex]4.83\times 10^{-19} J[/tex] is the energy of exactly one photon of this light.

                We will neither give the Hypertonic Solution nor the Isotonic Solution but the patient will be given an Hypotonic Solution.

As the patient is taken for heat stroke and has resulted in dehydration so it means that the water content in the cells of the patient has been decreased and the solute content is being increased. Hence, this case is known as Hypertonicity. So, in order to make the concentration of water and solute balance (Isotonicity) on both sides (inside and outside the cells) we should administer an Hypotonic solution into the patient body. Therefore, the higher concentration of solutes in cells will drag the water content from hypotonic solution and gradually the process will attain an isotonic environment.

An isotonic solution, which has the same osmolarity as the cell, is beneficial in rehydrating a dehydrated patient. This is because it ensures no net movement of water, maintaining cell volume and function. Hypertonic solutions, on the other hand, can cause cells to shrink due to water loss and should be avoided.

In the case of Jeanie who was taken to the emergency room for heat stroke and dehydration, an isotonic solution would be most beneficial. Isotonic solutions have the same osmolarity as the cell, meaning the concentrations of solute (salts, minerals, etc.) and solvent (water) are equal within the cell and in the solution. This results in no net movement of water into or out of the cell, although water will still move in and out, ensuring the cell does not become compromised.

Compared to hypertonic solutions, which would result in water leaving the cell due to a higher concentration of solute outside the cell, isotonic solutions are beneficial in rehydration. A hypertonic solution can cause cells to shrink due to water loss, which can negatively impact overall cell function. Therefore, in the situation of rehydrating a dehydrated patient, isotonic solutions are preferred to hypertonic solutions.

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A mixture is formed of two substances (molecules, elements, compounds, etc.) that are not chemically bonded. A compound is formed of two substances chemically joined together, so the answer is A.

Answer:

a. the substances in a compound are chemically joined in a fixed proportion.

Explanation:

A compound is defined as a pure substance that has more than one element. Compounds have a fixed composition. This means that a compound always has the same elements with equal percentages by mass. Meanwhile, a mixture is made up of two or more components that are mixed, but are not chemically combined.

Hi Khal75,

Experiment: How to seperate sand.

Answer - separated using a filter; not soluble in water

Sand is not soluble in water. If you heat it all the water will dissolve but the sand will not.

Pressure of argon = 546.8 kPa

Conversion factor: 1 atm = 101.325 kPa

Pressure of argon = 546.8 kPa x 1 atm/101.325 kPa = 5.4 atm

Moles of argon = 15.82

Volume of argon = 75.0 L

According to Ideal gas law,

PV = nRT

where P is the pressure, V is the volume , n is the number of moles, R is the universal gas constant, and T is the temperature

T = PV/nR = (5.4 atm x 75.0 L) / (15.82 x 0.0821 L.atm.mol⁻¹K⁻¹)

T = 311.82 K

Hence the temperature of the canister is 311.82 K.

Answer:

311.82

Explanation:

Si, silicon. The oxide is SiO2, silicon dioxide. ...

Na, sodium. The oxide is Na2O. It is introduced as a white powder called soda ash.

Ca, calcium. The oxide is CaO. ...

Pb, lead. The oxide is PbO. ...

K, potassium.

From almost the creation of the first true maps of the Earth, people started seeing how continents would be able to fit together.  In particular, people noticed that South America fits almost exactly into Africa.

It is now known that most of the major continental masses can be fit together in a jigsaw process.   In fact we now know that the continents were indeed once all joined together as one land mass  the super continent of Pangaea.

If you look at most world maps you will ponder how this is evidence, as the continents really don’t appear to ‘fit’ together very well.

The correct answer is option D, confirmation bias.

Confirmation bias is the tendency to interpret data in a way that confirms the already designed hypotheses.  

As the two scientists interpret the data (or experimental result) in different ways to adhere to the different hypotheses, this is indicative of cognitive bias. This is also called inductive reasoning where the premise is viewed as evidence for the validity of the conclusion.  

This is an example of confirmation bias.

The term confirmation bias in experiment refer to a situation in which the experimental leans more towards evidences that confirm his/her hypothesis rather than evidences that disprove it.

This type of bias creates a sort of self fulfilling prophecy. The conclusions of the research merely echoes his/her believes and contrary evidences are not given proper consideration.

If two scientists carry out the same experiment having different hypothesis and arrive at different conclusions from the same experimental results; then each of them merely confirmed his/her beliefs without considering the experimental results fairly.

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According to ideal gas equation, there are 1.55 moles in the sample of gas.

To calculate the number of moles in a sample of gas, we can use the Ideal Gas Law equation: [tex]PV=nRT[/tex] where P is the pressure of the gas, V is its volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.

We can rearrange the Ideal Gas Law equation to solve for n:

[tex]n=\dfrac{PV}{RT}[/tex]

Given:

V = 27.5 L

T = 302 K

P = 1.40 atm

We can use the gas constant, R, which is 0.0821 L·atm/mol·K.

Plugging in the values:

[tex]n=\dfrac{1.40}{0.0821}[/tex]×[tex]\dfrac{27.5}{302}[/tex]

=1.55 moles

Therefore, the number of moles in the sample of gas is 1.55 moles. Hence, option C is correct.

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Answer : 135 grams of sodium has 5.869 moles.

Solution : Given,

Mass of sodium = 135 grams

Molar mass of sodium = 23 g/mole

Formula used :

[tex]\text{Moles of sodium}=\frac{\text{Mass of sodium}}{\text{Molar mass of sodium}}[/tex]

Now put all the given values in this formula, we get

[tex]\text{Moles of sodium}=\frac{135g}{23g/mole}=5.869moles[/tex]

Therefore, the moles of sodium present in 135 grams of sodium is, 5.869 moles.