Potassium is isotopic and has RAM of 39.5 work out the percentage abundance of each isotope in a given sample of potassium which is found to contain 3 isotopes of K-39, K-40 and K-38 with the abundance of K-38 being 0.01%

Answer:

The answer is D. H+ increases in solution.

Explanation:

One water molecule gains a hydrogen and therefore takes on a positive charge, while the other water molecule loses a hydrogen atom and therefore becomes negatively charged.

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Answer:  pH = 7.36. The pKa of H2PO4− is 7.21.

Explanation:

Answer:1. A.   2.C    3.true

Explanation:

Answer: The number of moles of [tex]NaCl[/tex] produced will be, 3.61 moles.

Explanation : Given,

Mass of [tex]Na[/tex] = 83.0 g

Molar mass of [tex]Na[/tex] = 23 g/mol

First we have to calculate the moles of [tex]Na[/tex]

[tex]\text{Moles of }Na=\frac{\text{Given mass }Na}{\text{Molar mass }Na}[/tex]

[tex]\text{Moles of }Na=\frac{83.0g}{23g/mol}=3.61mol[/tex]

Now we have to calculate the moles of [tex]NaCl[/tex]

The balanced chemical equation is:

[tex]2Na+Cl_2\rightarrow 2NaCl[/tex]

From the reaction, we conclude that

As, 2 mole of [tex]Na[/tex] react to give 2 mole of [tex]NaCl[/tex]

So, 3.61 mole of [tex]Na[/tex] react to give 3.61 mole of [tex]NaCl[/tex]

Therefore, the number of moles of [tex]NaCl[/tex] produced will be, 3.61 moles.

Answer:

2.57

Explanation:

Answer:

d.electrons

Explanation:

Answer:

                        5.68 mol of CO₂

Explanation:

                    Mole is a chemical unit used to determine the amount of a substance also referred as chemical amount.  Also, it represents 6.022 × 10²³ of an entity. For example, 1 mole of Magnesium metals contains 6.022 × 10²³ atoms.

Mole is given as,

                                         Moles = Mass / M.Mass

This equation shows that when the mass of a substance is given then one can calculate its moles by dividing its mass by M.Mass or Atomic Mass.

As we know the M.Mass of CO₂ is 44.01 g/mol therefore, the moles are calculated as,

Moles  =  250 g / 44.01 g/mol

Moles  =  5.68 mol of CO₂

Answer:

Lead carbonate is not reacted with sulphuric acid in the formation of carbon dioxide because lead is insoluble in water. The reason is that lead is non polar substance and water is polar solvent means it makes positive and negative poles. Only polar solute dissolve in polar solvent and non polar solute dissolve in non polar solvent. So that's why lead carbonate do not dissolve in water and makes a layer on the water.

Explanation:

The correct option is D.

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

That is, water has a high heat of vaporization, the amount of energy needed to change one gram of a liquid substance to gas at a constant temperature. Water's heat of vaporization is around 540 cal/g at 100 °C, water's boiling point.

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Answer: Option D. There is no net change to the system.

Explanation:

Answer: The n in Bohr model of the atom is principle quantum number.

The Rydberg n integer stats represent electron orbits at various integral distances from the atom in Bohr's conceptualization of the atom. Subsequent models discovered that the values for n1 and n2 match the two orbitals ' principle quantum numbers.

Explanation: pls mark brainliest :,)

Final answer:

In the Rydberg equation, n1 is related to the principal quantum number n in the Bohr model, where n1 is the lower energy level an electron transitions from, and n2 is the higher energy level it transitions to.

Explanation:

In the Rydberg equation, n1 and n2 represent the principal quantum numbers corresponding to the initial and final energy levels of an electron in a hydrogen atom, respectively. When an electron transitions between these energy levels, it emits or absorbs a photon whose energy corresponds to the difference in energy between these levels.

The Bohr model describes an electron's energy levels in terms of quantum numbers; thus, the quantum number n in the Bohr model is directly related to n1 and n2 in the Rydberg equation. Specifically, n1 corresponds to the lower energy level (initial state) and n2 to the higher energy level (final state) of an electron's transition.

For example, in the Balmer series, the final energy level nf is always 2, while the initial level ni is greater than nf (e.g., ni = 3, 4, 5, ...). The transitions between these levels give rise to visible light of specific wavelengths, as dictated by the Rydberg formula.

Answer:

Molality of the solution :  0.630 M

Mass of the KBr (solute) = x grams

Mass of the solvents : 86.0 - x grams

Mass of the solute = 6.001 grams

Mass of the solvent = 86.0 - x grams = 86.0 - 6.001 g = 79.999 grams

Explanation:

A 0.510m aqueous solution of KBr has a total mass of 67.0g. The masses of solute and solvent are 3.833g and 63.167 g.

The two main elements of a solution are a solute and a solvent. The solute is a substance that dissolves. The former dissolves in the solvent, which has that property. In other terms, the solvent is the dissolving media, and the solute is the stuff that is dissolved.

The solute, which is present in a solution in a smaller quantity than the solvent, is the substance that dissolves in the solvent. The term "solvent" refers to the substance that dissolves the solute in a solution; it is more abundant than the solvent.

Greater than the solvent is the boiling point. That is less than the solute's level.

Solute as a solid, liquid, or gas. Solvent is primarily liquid, but it can also be gaseous.

The qualities of the solute determine its solubility. The solvent's characteristics affect how something dissolves.

let the mass of solute be x g

mass of solvent= (67- x) g

Molality = [tex]\frac{x X 1000}{119(67-x)}[/tex]

solving for x:

x = 3.833g

67 - x = 63.167 g

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Answer:

Its c.

Explanation:

When the density and temperature at the core of the gravitationally collapsing nebula reaches values when nuclear fusion is triggered and sustained, that marks the birth of the star.

‘ you don’t likeee me dasss fineee kk byeee’

Answer: It will move down

Explanation: Since there is an unbalanced force on the object its motion is directed on the side with the greatest amount of force.

Final answer:

With a net force of 5N downward, the object will accelerate downward.

Explanation:

If one force on an object is exerted 5N upward and another force is 10N downward, we can calculate the net force to determine the object's motion. By subtracting the upward force from the downward force, we get a net force of 10N - 5N = 5N downward. Since the net force is downward, the object will accelerate in the downward direction according to Newton's Second Law of Motion, assuming no other forces are acting on the object.

C. Tripling the length and reducing the radius by a factor of 2 is the change to a pipe would increase the conductance by a factor of 12.

Explanation:

As we know that the resistance is directly proportional to the length of the pipe and it is inversely proportional to the cross sectional area of the pipe.

So it is represented as,

R∝ l /A [ area is radius square]

So k is the proportionality constant used.

R = kl/A

Conductance is the inverse of resistance, so it is given as,

C= 1/R.

R₁ = kl₁ / A₁

R₂ = kl₂/A₂

R₂/R₁ = 1/12 [∵ conductance is the inverse of resistance]

        = l₂A₁ / l₁A₂

If we chose l₁/l₂= 3 and A₂/A₁= 4 So R₂/R₁= 1/3×4 = 1/12

So tripling the length and reducing the radius by a factor of 2 would increase the conductance by a factor of 12.

Answer:

Reducing the length by a factor of  1/3 and doubling the radius.

Explanation:

this is correct answer, my assignment says

The air pressure on the beach in Hawaii is greater than on top of Mauna Kea due to the greater altitude of Mauna Kea, which has less atmospheric mass above it exerting force. The atmospheric pressure is more substantial at sea level, where the complete atmosphere is overhead. Despite the large force exerted by air pressure when sunbathing on the beach, equal pressure inside the body allows one to easily stand up.

The air pressure on the beach in Hawaii is greater than the pressure on top of Mauna Kea due to differences in altitude. Atmospheric pressure decreases with altitude because the density of air molecules decreases as you go higher in the atmosphere; there are fewer air molecules above a given area exerting less force. At sea level, the pressure is at its highest because the full column of the atmosphere is above that point. In contrast, at the peak of Mauna Kea, which is 4.2 kilometers high, the column of air above it is significantly shorter, resulting in a lower pressure.

When lying on the beach sunbathing, the large force of atmospheric pressure, which is roughly equal to 10 tons, is exerted over the entire surface area of your body. However, because this pressure is exerted uniformly in all directions, your body's internal pressure, which is adjusted to the external atmospheric pressure, allows you to stand up without being crushed.

Answer:

20600 Calories

Explanation:

chromium(VI) oxide

chromium(IV) oxide

chromium(IIl) oxide

chromium(ll) oxide

CrO-

CrO2-

CrO3-

Cr2O3-​

The final pressure will be 405.3 kilopascals.

According to the Boyle's Law, the pressure of the gas is inversely proportional to the volume of the gas as the temperature of the gas remains constant.

So,PV = Constant.

Here in this question, the volume of the container is halved.

Let the Pressure of the gas initially be P1 and final pressure be P2. Volume of gas initially be V

So, according to Boyle's Law,

P₁V₁ = P₂V₂PP.

So, [tex]2 \times V[/tex] = P₂[tex]\frac V2[/tex].

So, P2 = 4 atm.

1atm = 101.325 kilo pascals.

So, 4 atm = [tex]4\times101.325[/tex] kilopascals. = 405.3 kilopascals.

Answer: D

Explanation:

it says so on google

When light fall on the different object. There will be an interaction between light and matter. It may happen interaction, reflection, refraction. Wave bounce off process is known as reflection.

If the surface is smooth and shiny, like glass, water or polished metal, the light will reflect at the same angle as it hit the surface. Reflection is the change in direction of a wave at the surface of two different media so that the wave returns into the medium from the same.

Refraction light waves change speed when they pass across the two substances with different density. Resonance is when electromagnetic waves can make thing vibrate. Interference is not bounce off phenomena.  

Light have dual nature, sometime it behaves as a particle and sometimes it behaves as a wave.

Thus, the bounce back of the light is called the reflection of light.

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Answer:

1. Flower

- contain the sexual organs of the plant

- attract insect for pollination

- produce fruit carries the seed during fertilization.

2. Leaf

- capture sunlight for photosynthesis

- responsible to make food

- evaporate water molecules

- movement of oxygen and carbon dioxide in and out to plant

3. Stem

- transport water and nutrients from root to leaves.

- support leaves and branches

- in some plants are photosynthetic

4. Root

-provide support by anchoring the plant

- absorb water and nutrients for growth

- store sugars and carbohydrates to perform other functions

Answer:

                     127.15 °C

Explanation:

                    Gay-Lussac's law states that the pressure of a given mass of gas directly proportional to the absolute temperature of the gas at constant volume.

Mathematically,

                                           P₁ / T₁  =  P₂ / T₂   -----(1)

Data Given:

                  Initial Pressure  =  P₁  =  1 atm (assumed)

                  Initial Temperature  =  T₁  = -73°C =  200.15 K

                  Final Pressure  =  P₂  =  2 atm (doubled)

                  Final Temperature  =  T₂  =  ????

Solving equation 1 for T₂,

                                           T₂  =  P₂ × T₁ / P₁

Putting these values;

                                           T₂  =  2 atm × 200.15 K / 1 atm

                                           T₂  =  400.3 K

Or,

                                           T₂  =  127.15 °C

Conclusion:

                  By doubling the pressure results in increase in temperature.

The final temperature of the gas, when its pressure is doubled and volume held constant, increases from -73°C to 127°C.

To determine the final temperature of a gas when its pressure is doubled and volume remains constant, we use the Ideal Gas Law which can be expressed as PV = nRT.

Given the initial temperature (T1) is -73°C, which converts to 200 K (273 - 73), and the initial pressure (P1) is doubled to P₂= 2P₁, the formula becomes:

To find T₂ isolate T₂:

Thus, the final temperature of the gas in degrees Kelvin is 400 K.

To convert back to degrees Celsius, subtract 273:

The final temperature of the gas is 127°C.

Answer:

Sweating

Explanation:

When you sweat, you lose water that your body needs to function.

Sweating because running in a hot day you can sweat 3-4 liters of fluid per hour

Answer: 33.3 L

Explanation: solution attached:

Convert mass of H2O to moles

Convert 134°C to Kelvin

134°C + 273 = 407 K

Derive the ideal gas equation for V:

V = nRT /P

Substitute the values.

When food spoils inside a can, bacteria produce gas as a byproduct of fermentation and decomposition. This gas increases pressure within the can, risking deformation or bursting, especially at higher temperatures. Additionally, terminal corrosion can further contribute to spoilage and container failure.

Inside a can of spoiled food, gas production occurs due to the fermentation process and decomposition carried out by bacteria. When food spoils, bacteria break down organic matter, producing gases such as hydrogen sulfide or methane as byproducts. These gases can cause pressure increase within the sealed environment of the can, potentially leading to deformation or bursting of the container if left unchecked.

Reactions and Consequences

As spoilage progresses, the pressure inside the can rises due to the accumulation of gases. Given that the can is a rigid container, its inability to expand means that the growing number of gas molecules continue to strike the can's walls with increasing force. This is further exacerbated when the temperature of the environment rises, as it gives the gas molecules more kinetic energy, causing more frequent and forceful collisions, leading to a drastic increase in pressure that could result in the can bursting.

Additionally, terminal corrosion of the can may occur towards the end of its service life, where the protective coating is depleted, allowing corrosion and pitting of the can. If the internal environment remains anaerobic, electrochemical anodic reactions can lead to further gas formation and eventual pinholing of the can body, compromising its hermetic seal and leading to spoilage or contamination of the food product.

Answer: 90 g O2

Explanation: soution attached:

Balance first the chemical equation

CH4 + O2 => CO2 +2H2O

Convert mass of CH4 to moles

Use the mole ratio of CH4 and O2 from the balanced equation.

Convert moles of O2 to mass using the molar mass of O2.

The correct characteristics of medusae are: swim freely, have tentacles, mouths open downward.

Medusae are the free-swimming, jellyfish-like form of certain aquatic animals, typically found in the phylum Cnidaria. They are characterized by their ability to swim freely in the water, which distinguishes them from the sessile, or immobile, polyps that are another life stage of cnidarians. Medusae have tentacles that hang down from their bell-shaped bodies, which they use to capture prey. These tentacles are often equipped with stinging cells called nematocysts that help to immobilize their prey. The mouth of the medusa is located on the underside of the body, facing downward, and leads to a gastrovascular cavity where digestion takes place.

To summarize, the following are the characteristics of medusae:

- Swim freely: Medusae are capable of locomotion and can move through the water column.

- Have tentacles: They possess tentacles that extend from their bodies, which are used for capturing food.

- Mouths open downward: The mouth is situated on the ventral side of the medusa, facing downward, which is suitable for bringing captured prey into the gastrovascular cavity for digestion.

The other options listed do not accurately describe medusae:

- Are sessile: This is incorrect because medusae are free-swimming, not immobile.

- Lack tentacles: This is incorrect because tentacles are a defining feature of medusae.

- Mouths open upward: This is incorrect because the mouth of a medusa opens downward.

Answer:

B

Explanation:

Answer:

Among the different types of scientific knowledge  hypotheses are likely to be modified or discarded most frequently. Long ago in the 1600's scientists discarded the phlogiston theory because the new evidence didnt support it.

Explanation:

Hypothesis is the assumption of something possible or impossible to draw a consequence and is provisionally established as the basis for an investigation and which can confirm or deny its validity. For this reason, within scientific research, hypotheses are so important and so changeable that they are modified or discarded more frequently within scientific knowledge.

Based on a work by Johann Joachim Becher, the German scientist Georg Ernst Stahl created the phlogiston theory that said combustion occurred with certain materials because they had an “element” or a common flammable principle that was released at the time of burning . This theory was abandoned because there was no evidence, even through scientific experiments, to prove that this theory is true.

Hypotheses are likely to be modified or discarded most frequently in scientific knowledge. Phlogiston theory was discarded due to evidence contradicting its predictions.

Among the different types of scientific knowledge, hypotheses are likely to be modified or discarded most frequently. Long ago, in the 1600s, scientists discarded the phlogiston theory because evidence contradicted the predictions made by the theory. Phlogiston theory proposed that a substance called phlogiston was released during combustion, but experiments showed that substances gained weight instead of losing weight during combustion.

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