What is the empirical formula of a compound composed of 30.5 g potassium (k) and 6.24 g oxygen (o)?

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.

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.

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.

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:

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.

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.

Learn more: https://brainly.com/question/13044778

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.

https://brainly.com/question/14659030

#SPJ3

                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.

https://brainly.com/question/13886457

#SPJ3

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)

Hello!

To find the amount of atoms that are in 80.45 grams of magnesium, we will need to know Avogadro's number and the mass of one mole of magnesium.

Avogadro's number is 6.02 x 10^23 atoms, and one mole of magnesium is equal to 24.31 grams.

1. Divide by one mole of magnesium

80.45 / 24.31 = 3.309 moles (rounded to the number of sigfigs)

2. Multiply moles by Avogadro's number

3.309 x (6.02 x 10^23) = 1.99 x 10^24 (rounded to the number of sigfigs)

Therefore, there are 1.99 x 10^24 atoms in 80.45 grams of magnesium.

80.45 g of magnesium contains approximately 1.99 x 10^24 atoms calculated by converting the mass to moles and then using Avogadro's number to convert to atoms.

The question is asking how many atoms are in 80.45 g of magnesium. To find the answer we first need to determine how many moles of magnesium are in 80.45 g. The atomic mass of magnesium is approximately 24.31 g/mol. To calculate the number of moles divide the mass by the atomic mass, which gives us approximately 3.31 moles of magnesium.

Then we use Avogadro's number which is 6.022 x 10^23 atoms/mol, to determine the number of atoms in 3.31 moles of magnesium. We get approximately 1.99 x 10^24 atoms of magnesium in 80.45 g.

https://brainly.com/question/31146739

#SPJ3

Answer. 12 km/hr and 2 m are scalar quantities.

Explanation

Scalar quantities are those quantities which only have magnitude but no direction, for example: speed, time, mass etc.

Vector quantities are the quantities which have both magnitude and direction,for example : acceleration, momentum etc.

5 m northeast and 2 m north are vector quantities telling us magnitude and direction both that is 5 m in north east direction and 2 m in north direction.  

12 km/hr and 2 m are scalar quantities telling us only speed and distance respectively without specific directions.

Final answer:

Scalar quantities have magnitude but no direction; examples include 2 m and 12 km/hr. Temperatures like -5°C are scalar since they do not have a direction. A stopwatch is a device that measures time, with the movement of the seconds hand indicating a change in time

Explanation:

Understanding Scalar Quantities

In physics, scalar quantities are defined as measurements that have magnitude but no specific direction. Measurements that are scalar quantities include temperatures, distances without a specified direction, energies, speeds, and ages. For the examples provided, 2 m and 12 km/hr are scalar quantities because they specify a magnitude but do not indicate any direction. However, distances with specified directions (such as '5 mi northeast' and '2 m north') are not scalar because they include directional information, making them vectors.

Addressing the specific examples from the conceptual questions:

The temperature predicted to be -5°C is a scalar quantity since temperature has magnitude but no direction. The negative sign here does not indicate direction, but rather a point on the temperature scale.

An example of a device used to measure time is a stopwatch. When the seconds hand moves, it indicates a change in time.

From the given measurements of acceleration with directions (e.g., '3 N north, 4 N west'), it is apparent that these are not scalar quantities but vectors. Scalar quantities never involve the specification of directions and are therefore not represented by arrows.

5 a) Mass = 6.0 × 10²⁴ kg; d = 12 × 10⁶ m

[tex]r  = \frac{1}{2}d = \frac{1}{2} \times 12 \times10^{6}\text{ m} = 6.0 \times 10^{6} \text{ m}\\[/tex]

[tex]V = \frac{4}{3} \pi r^{3} = \frac{4}{3} \pi \times (6.0 \times 10^{6} \text{ m})^{3} = 9.05 \times 10^{20} \text{ m}^{3}\\[/tex]

[tex]\text{Density} = \frac{\text{Mass}}{\text{Volume}} = \frac{6.0 \times 10^{24}\text{ kg}}{9.05 \times 10^{20} \text{ m}^{3}} = \text{6600 kg/m}^{3}\\[/tex]

The average density is 6600 kg/m³.

5 b) Mass = 2.0 × 10³⁰ kg; Diameter = 1.4 × 10⁶ km  

[tex]r  = \frac{1}{2}d = \frac{1}{2} \times 1.4 \times10^{9}\text{ m} = 7.0 \times 10^{8} \text{ m}\\[/tex]

[tex]V = \frac{4}{3} \pi r^{3} = \frac{4}{3} \pi \times (7.0 \times 10^{8} \text{ m})^{3} = 1.43 \times 10^{27} \text{ m}^{3}\\[/tex]

[tex]\text{Density} = \frac{\text{Mass}}{\text{Volume}} = \frac{2.0 \times 10^{30}\text{ kg}}{1.43 \times 10^{27} \text{ m}^{3}} = \text{1400 kg/m}^{3}\\[/tex]

The average density is 1400 kg/m³.

5 c) Venus and the Sun are most like the objects in Parts a) and b). Venus has the greater density

6 a) Mass = 4.8 × 10²² km; Diameter = 3.1 × 10⁶ m

[tex]r  = \frac{1}{2}d = \frac{1}{2} \times 3.1 \times10^{6}\text{ m} = 1.55 \times 10^{6} \text{ m}\\[/tex]

[tex]V = \frac{4}{3} \pi r^{3} = \frac{4}{3} \pi \times (1.55 \times 10^{6} \text{ m})^{3} = 1.56 \times 10^{19} \text{ m}^{3}\\[/tex]

[tex]\text{Density} = \frac{\text{Mass}}{\text{Volume}} = \frac{4.8 \times 10^{22}\text{ kg}}{1.56 \times 10^{19} \text{ m}^{3}} = \text{3100 kg/m}^{3}\\[/tex]

The average density of the moon is 3100 kg/m³.

6 b) The satellite appears to consist mostly of silicate rock.

The number of total atoms in 0.290 g of P2O5 is approximately [tex]\boxed{8.62 \times 10^{20}} atoms.[/tex]

To determine the number of total atoms in 0.290 g of P2O5, follow these steps:

 1. Calculate the molar mass of P2O5.

 - The molar mass of phosphorus (P) is approximately 30.97 g/mol.

 - The molar mass of oxygen (O) is approximately 16.00 g/mol.

 - The molar mass of P2O5 is (2 — 30.97 g/mol) + (5 — 16.00 g/mol) = 61.94 g/mol + 80.00 g/mol = 141.94 g/mol.

 2. Determine the number of moles in 0.290 g of P2O5.

 - Number of moles = mass / molar mass.

 - Number of moles of P2O5 = 0.290 g / 141.94 g/mol = 0.002043 mol.

 3. Calculate the number of atoms in one mole of P2O5.

 - One mole of P2O5 contains 2 moles of phosphorus atoms and 5 moles of oxygen atoms.

 - Total atoms per mole of P2O5 = 2 + 5 = 7 moles of atoms.

 4. Multiply the number of moles of P2O5 by Avogadro's number (approximately 6.022 — 10^23 atoms/mol) and the number of atoms per mole to find the total number of atoms.

 - Total atoms = number of moles — Avogadro's number — total atoms per mole.

 - Total atoms = 0.002043 mol — 6.022 × 10^23 atoms/mol — 7 atoms/mole =ˆ 8.62 — 10^20 atoms.

 Therefore, the number of total atoms in 0.290 g of P2O5 is approximately [tex]\boxed{8.62 \times 10^{20}} atoms.[/tex]

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.

Find out more at https://brainly.com/question/13553504.

Hello  Bobby792003

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

:)

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.

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.

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.

https://brainly.com/question/31861824

#SPJ3

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.

a ) it gains electrons

Answer: Option (A) is the correct answer.

Explanation:

According to the octet rule, every atom has the tendency to completely fill its octet and for that it needs to occupy eight electrons in its valence shell.

For example, atomic number of oxygen atom is 8 and its electronic distribution is 2, 6.

And in order to completely fill its valence shell and attain stability an oxygen atom needs to gain two electrons from another atom.

Thus, we can conclude that oxygen obey the octet rule when reacting to form compounds as it gains electrons.

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

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.

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.

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.

Learn more about Reversible Reactions here:

https://brainly.com/question/31950205

#SPJ6

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.