Natural selection is the primary mechanism of _______.
A.
reproduction
B.
biodiversity
C.
adaptation
D.
evolution

Answer:

The answer should br C

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:

1 Count the atoms of each element in the reactants and the products. 2 use coefficient place them in front of the compound as needed.

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

All matter is made up of atoms is the characteristics that John Dalton included in his description.

Explanation:

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.

Answer:

Metamorphic rock is classified by texture and composition. The texture of a metamorphic rock can be either foliated and appear layered or banded, or non-foliated and appear uniform in texture without banding. Foliated rocks contain many different kinds of minerals, but non-foliated rocks contain only one main mineral, which contributes to their more uniform appearance.  Igneous rocks are classified according to mode of occurrence, texture, mineralogy, chemical composition, and the geometry of the igneous body.

Explanation:

Answer:

NaI

Explanation:

The formula for sodium iodide is NaI

It is a compound (ionic compound) formed by the chemical reaction between sodium, Na and iodine.

The sodium is a metal in group 1 with atomic number 11 and mass number 23 ,it has one valence electron which it gives out to form a cation of +1 charge and the iodine is in group 7(halogen family) with atomic number 57 and mass number 23 and it has 7 valence electrons which allows it attract 1 electron to form an anion(iodide) of charge -1.

The reaction of sodium ion with iodide ion form the sodium iodide where sodium releases its one valence electron and iodine receives it which makes it balance that is they react in ratio 1:1 and thus have a chemical formula of NaI.

NaI has atomic mass of 150g/mole that is 127 + 23 = 150

Where

Na=23g/mol, I = 127g/mol

NaI is used mainly as nutritional supplement

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chromium(VI) oxide

chromium(IV) oxide

chromium(IIl) oxide

chromium(ll) oxide

CrO-

CrO2-

CrO3-

Cr2O3-​

Answer:

2nd and last.

Explanation:

In the first equation,the number of hydrogen atoms is not balanced and in the third,the number of aluminum atoms is not balanced.

Answer:

1. Fe 2 O 3 + 3H 2 2Fe + 3H 2 O

2. CaCO 3 CaO + CO 2

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.

1.08 atm is the pressure for a certain tire in atmosphere.

Explanation:

One kilo pascal (1 kPa) corresponds to 1000 pascal. Another common unit used for pressure is atmosphere (symbolised as ‘atm’). 1 atm refers the standard atmospheric pressures and corresponds to 760 mm Hg and 101.3 kPa. Atmospheric pressures are commonly referred as square inches (psi)/ pounds.

  [tex]1 \mathrm{atm}=101.3 \mathrm{kPa}=101,325 \mathrm{Pa}=760 \mathrm{mm} \mathrm{Hg}=760 \text { torr }=14.7 \mathrm{lb} / \mathrm{in}^{2}(\mathrm{psi})[/tex]

Given:

The air pressure for a certain tire = 109 kPa

We need to find pressure in atmospheres

So, we know,

1 atm = 101.3 kPa

Hence,

[tex]\frac{109 \mathrm{kPa}}{1} \times \frac{1 \mathrm{atm}}{101.3 \mathrm{kPa}}=1.076=1.08 \mathrm{atm}[/tex]

1.08 atm is the pressure for a certain tire in atmosphere.

The pressure in atmosphere is = 1.08 atmosphere.

The atmospheric pressure can be measured using a barometer in units of measurement called atmospheres or bars.

To convert 109 kPa pressure to atmosphere,

101.325 kPa = 1 atm

109 kPa = X

Cross multiply to solve for x,

[tex]x = \frac{1 \times 109}{101.325} [/tex]

X = 1.075

X = 1.08 atmosphere.

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Answer: C

Explanation: The answer is c because of the H2+CI1--> 2HCI

Answer:

                      %Copper  =  25.42 %

Explanation:

                    For solving this problem one first write down the half reactions as;

Reduction of Cu²⁺ to Cu⁺¹ by I⁻:

                                2 Cu²⁺  +  4 I⁻   →   2 CuI  +  I₂

Secondly, the titration reaction between Na₂S₂O₃ with I₂ as;

                             2 S₂O₃²⁻  +  I₂   →   S₄O₆²⁻  +  2 I⁻

Now, Calculate Moles of S₂O₃²⁻ as;

                             Moles  =  Molarity × Volume

Putting values,

                             Moles  =  0.1 mol/L × 0.02 L

                             Moles  =  0.002 moles of S₂O₃²⁻

From first two equations we can conclude that,

2 moles of S₂O₃²⁻ liberated I₂ produced by  =  2 moles of Cu²⁺

So,

0.002 moles of S₂O₃²⁻ will liberate I₂ produced by  = X moles of Cu₂⁺

Solving for X,

                       X =  0.002 mol × 2 mol / 2 mol

                       X  =  0.002 mol of Cu²⁺

So, we require 0.002 moles of Cu²⁺ to produce I₂ enough for titrating with 0.1 M (20.00 mL) sodium thiosulphate solution.

Now, Calculate mass of Copper as,

                       Mass  =  Moles  ×  A.Mass

                       Mass  =  0.002 mol × 63.55 g/mol

                       Mass  =  0.1271 g of Copper

Lastly, calculate % copper as,

                       %Copper  =  0.1271 g / 0.500 g × 100

                       %Copper  =  25.42 %

Final answer:

To calculate the percent copper in a sample using iodometric titration, the amount of sodium thiosulphate used in the titration reveals the moles of copper present. The mass of copper is then calculated, allowing us to find that the sample is 25.42% copper.

Explanation:

To determine the percent copper in the sample using iodometric titration, we first need to understand the chemistry involved. The reaction between Copper (II) and iodide produces iodine, which is then titrated with sodium thiosulphate. The formula for calculating the percent copper is based on the stoichiometry of these reactions.

Given that 20.00 [tex]cm^3[/tex] of 0.1 M sodium thiosulphate is required, we can calculate the moles of sodium thiosulphate reacted: Moles of sodium thiosulphate = 20.00 [tex]cm^3[/tex] × 0.1 mol/L = 0.0020 mol.

Sodium thiosulphate reacts with iodine in a 1:1 molar ratio, meaning 0.0020 mol of iodine was produced. The stoichiometry between copper (II) and iodine is also 1:1, so 0.0020 mol of Copper (II) was initially present. The molar mass of Copper (II) is 63.546 g/mol, hence the mass of copper in the sample is 0.0020 mol × 63.546 g/mol = 0.1271 g.

To find the percent copper, we then use the formula: Percent Copper = (Mass of Copper in the Sample / Total Mass of the Sample) × 100 = (0.1271 g / 0.500 g) × 100 = 25.42%.

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:

                        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

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: 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:

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:

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:

Answer:

The number of molecules = 2.6408 molecules

Explanation:

To determine the number of molecules in water, we need to determine how many moles of water we have

Water has a molar mass of 18.015g/mol, this means that one mole of water molecules has a mass of 18.015g

To find the number of molecules,

7.9g * 1 mole H2O/ 18.015g

= 0.4385mole of H2O

Using avogadro number,

0.4385 H2O * 6.022* 10^23molecules/ 1 mole of H2O

That's 0.4385 H2O multipled by 6.022*10^ 23 molecules divided by 1 mole of H2O

Which gives == 2.6408 molecules

Answer: m= 6.2 g Ba

Explanation: Solution:

0.045 moles Ba x 137 g Ba / 1 mole Ba

= 6.2 g Ba

Final answer:

To calculate the mass of barium that participated in a chemical reaction, multiply the number of moles (0.045) by the molar mass of barium (137.327 g/mol) to get the mass in grams, which is 6.1797 grams.

Explanation:

The question seems to contain a typographical error, as '0.045 miles of barium' is not a valid measure for the amount of a chemical substance. The correct measurement should likely be 'moles' rather than 'miles'. To calculate the mass of barium (Ba) that participated in a chemical reaction, you need to use the molar mass of barium.

Firstly, the molar mass of barium is 137.327 g/mol. Therefore, the calculation to find the mass from moles is:

Identify the number of moles given, which is 0.045 moles of barium.

Calculate the mass by multiplying the number of moles by the molar mass of barium (0.045 moles * 137.327 g/mol).

The result gives you the mass of barium in grams.

For example:

Mass of Ba = 0.045 mol * 137.327 g/mol = 6.1797 g

Therefore, the mass of barium that participated in the chemical reaction is 6.1797 grams.

Answer:

+1

Explanation:

From the question, the following were obtained:

Proton = 3

Neutron = 3

Electron = 2

From the above, we see clearly that the atom has loss 1 electron as the electron is lesser than the proton with 1. So, the atom has a charge of +1

The electrical charge of an atom is determined by subtracting the number of electrons from the number of protons. In this atom with three protons and two electrons, the overall charge is +1.

When considering the electrical charge of an atom, the important components to consider are the protons, which have a positive charge, and the electrons, which have a negative charge. Neutrons do not have a charge, so they do not contribute to the overall charge of the atom. In this case, the atom has three protonsand two electrons. Each proton has a charge of +1, and each electron has a charge of -1. Therefore, the overall charge of this atom is calculated by subtracting the number of electrons from the number of protons: 3 (protons) - 2 (electrons) = +1. So this atom has an overall charge of +1.

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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:

Al(NO3)3 + Ca(OH)2 = Al(OH)3 + Ca(NO3)2.

Explanation:

The balanced equation for the reaction between calcium nitrate and aluminum hydroxide is: Ca(NO3)2 + 2Al(OH)3 → 2Al(NO3)3 + 3Ca(OH)2.

The balanced equation for the reaction between calcium nitrate and aluminum hydroxide is:

Ca(NO3)2 + 2Al(OH)3 → 2Al(NO3)3 + 3Ca(OH)2

In this reaction, calcium nitrate reacts with aluminum hydroxide to produce aluminum nitrate and calcium hydroxide.

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Answer:

20600 Calories

Explanation:

Answer:

The total pressure of a mixture of gases is the sum of the partial pressures of the gases that make it up is described by Dalton's Law. The correct answer is OB) Dalton's law.

Dalton's law, also known as the law of partial pressures, states that the total pressure exerted by a mixture of non-reacting gases is equal to the sum of the partial pressures of the individual gases. In other words, each gas in a mixture contributes to the total pressure independently based on its own partial pressure. This law is applicable when the gases do not chemically react with each other and occupy the same volume.

Boyle's law (OA) describes the relationship between pressure and volume of a gas at constant temperature.

Charles's law (OC) relates the volume and temperature of a gas at constant pressure.

The combined gas law (OD) combines Boyle's, Charles's, and Gay-Lussac's laws to describe the relationship between pressure, volume, and temperature of a gas when all three variables change simultaneously.

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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:

V₂ = 630 L

Explanation:

Given data:

Initial volume = 350 L

Initial pressure = 1400 mmHg (1400/760 = 1.8 atm)

Final volume = ?

Final pressure = standard = 1 atm

Solution:

The given problem will be solved through the Boly's law,

"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"

Mathematical expression:

P₁V₁ = P₂V₂

P₁ = Initial pressure

V₁ = initial volume

P₂ = final pressure

V₂ = final volume

Now we will put the values in formula,

P₁V₁ = P₂V₂

1.8 atm × 350 L = 1 atm × V₂

V₂ = 630 atm. L/1 atm

V₂ = 630 L

To find the volume of gas at standard pressure, use Boyle's Law. Given an initial pressure of 1400 mm Hg and volume of 350L, at standard pressure (760 mm Hg) the volume would be 500L.

To determine the gas volume at standard pressure when given a volume at a different pressure, we can use Boyle's Law, which states that the product of pressure and volume is constant for a given amount of gas at a constant temperature (P1V1 = P2V2). Standard pressure (STP) is defined as 1 atm, which is equivalent to 760 mm Hg. The volume of the gas at STP can thus be calculated using the initial conditions:

V2 = (P1 * V1) / P2

Substitute the provided values:

P1 = 1400 mm Hg

V1 = 350 L

P2 = 760 mm Hg (standard pressure)

Now, rearrange the equation to solve for V2:

V2 = (1400 mm Hg * 350 L) / 760 mm Hg = 500 L

Thus, the volume of the gas at standard pressure would be 500 L.