what led to the mass extinction at the end of the cretaceous period?

Match each subatomic particle with the correct descriptions

Has a positive charge - proton

Has a negative charge - electron

Has a neutral charge = neutron

Found in nucleus of atom - proton and electron

Mass of 1 AMU - proton and neutron

Subatomic particle are the particle which is smaller than atom in size or of or relating to the inside of the atom

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Nitrous acid has the chemical formula HNO2. To determine the number of oxygen atoms in 15 mg of nitrous acid, we need to first calculate the number of moles of nitrous acid in 15 mg. The molar mass of nitrous acid is 47.013 g/mol.

Therefore, 15 mg of nitrous acid is equivalent to 0.000319 moles. In one molecule of nitrous acid, there are two oxygen atoms. Thus, the number of oxygen atoms in 15 mg of nitrous acid would be 0.000319 moles multiplied by 2 oxygen atoms, which is equal to 0.000638 oxygen atoms. Therefore, there are approximately 0.000638 oxygen atoms in 15 mg of nitrous acid.
To find the number of oxygen atoms in 15 mg of nitrous acid (HNO2), first determine the number of moles of nitrous acid. Nitrous acid has a molar mass of 1(H) + 14(N) + 16(O) * 2 = 47 g/mol. Divide the mass by the molar mass: 15 mg / 47 g/mol = 0.00032 mol (convert mg to g).

Now, find the moles of oxygen atoms in nitrous acid. Each molecule of HNO2 has 2 oxygen atoms. So, 0.00032 mol HNO2 * 2 = 0.00064 mol of oxygen atoms.

Finally, calculate the number of oxygen atoms using Avogadro's number (6.022 x 10^23 atoms/mol): 0.00064 mol * 6.022 x 10^23 atoms/mol = 3.85 x 10^20 oxygen atoms in 15 mg of nitrous acid.

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Answer:

80 g/mol

Explanation:

The Relative formular mass is the sum of the relative atomic masses of the elements present in the molecule.

TiO2;

There is one Ti atom and 2 O atom. Their atomic masses is given as;

TiO2 = 48 + 2(16) = 48  + 32 = 80 g/mol

Answer:

5 is the answer

Explanation:

I hope it helps you!

Answer:

I know the other person already said this but it would be the last option : )

Answer:

D

Explanation:

As bioindicators are the organism that indicate or monitor the health of the environment

Answer:

is D

Explanation:

Answer: C something that improves an organisms ability to survive

Answer:

C.

Explanation:

Answer:

Refer to explanation

Explanation:

Weather is the main cause behind most short term environmental changes

For example, a period of heavy rain may lead to a pond overflowing, and flooding the nearby shrubbery

Animals in the area would adapt to this by trying to keep away from the flooded area until it dries out, once the rain ends

The amount of oxygen required to produce 7 moles of H2O is 192 gram

In the chemical equation,

4NH3 + 5O2 → 6H2O + 4NO, 6 moles of water were produced from 5 moles of oxygen molecule.

Thus, to produce 7 moles of water we need 6 moles of oxygen.

We now have to convert moles to grams to find the amount of oxygen required to produce 7 moles of Water

Number of moles of oxygen = Mass / Molar mass

Number of moles of oxygen = 6 moles

Molar mass of oxygen = 32

6 = Mass / 32

Mass = 6 * 32 = 192 gram of oxygen

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Decimal number to its equivalent in scientific notation: 15 = 1.5 × 102, 0.015 = 1.5 × 10-2, 0.15 = 1.5 × 10-1, 150 = 1.5 × 101 and 1.5 = 1.5 × 100.

Notation is a system of symbols used to represent a set of ideas or concepts. It is used to communicate complex musical, mathematical, and scientific concepts. Notation helps to make information easier to understand and is widely used in many fields. Notation can range from simple symbols such as musical notes, to complex formulas and equations used in mathematics and science. It allows for the efficient and organized communication of ideas and can be used to represent abstract concepts. Notation makes it easier to understand and learn complex topics, and is an important tool for communication.

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Complete Question:

Match each decimal number to its equivalent in scientific notation
15
1.5
0.015
0.15
150
1.5 × 10-2
1.5 × 101
1.5 × 102
1.5 × 100
1.5 × 10-1

Explanation:

First, we need to rewrite the equation:

2K + 2H2O -> 2KOH + H2

This equation tells us that 2 moles of K react with 2 moles of H2O and produce 2 moles of KOH and 1 mole of H2.

If we have 43.7 grams of potassium, we can transform it into moles, compare with the ratio between Potassium and Hydrogen (H2) and then, calculate the quantity of hydrogen in grams.

So first, let's transform 43.7 grams of K into moles using the following formula:

moles = mass/molar mass

molar mass of K = 39.10 g/mol

moles = 43.7/39.10

moles = 1.12 moles

So:

2 moles of K --- 1 moles of H2

1.12 moles of K --- x moles of H2

2x = 1.12

x = 1.12/2

x = 0.559 moles of H2

Now let's transform moles into grams using the following formula:

mass = moles x molar mass

molar mass of H2 = 2.02 g/mol

mass = 0.559 x 2.02

mass = 1.13 g

Answer: It is produced 1.13 grams of H2.

A) The pH of a 0.75 M acetic acid solution, CH3COOH, Ka = 1.8 x 10⁻⁵: The pH is 2.92.

B) The calculated pH of a 0.75 M diethylamine solution, (CH3CH2)2NH, Kb = 7.1 x 10⁻⁴: The pH is 13.71

C) The hydronium ion concentrations can be represented as [H3O+]. the ratio of the hydronium ion concentrations in each solution is 1.59 x 10⁻¹¹.

A) The pH of a 0.75 M acetic acid solution, CH3COOH, Ka = 1.8 x 10⁻⁵: Firstly, we have the formula for Ka:

Ka = ([H3O+][CH3COO-]) / [CH3COOH]

We need to calculate [H3O+] and [CH3COO-].

Let us represent [H3O+] as x and [CH3COO-] as y.

Let [CH3COOH] be

0.75-x: [H3O+][CH3COO-] / [CH3COOH] = 1.8 x 10⁻⁵x

y / (0.75-x) = 1.8 x 10⁻⁵

x = [H3O+]

pH = - log[H3O+]

pH = - log (1.21 x 10⁻³)

The pH is 2.92.

B) The calculated pH of a 0.75 M diethylamine solution, (CH3CH2)2NH, Kb = 7.1 x 10⁻⁴:Given that Kb = 7.1 x 10⁻⁴.We know that

pKb + pKa = pKw (at 25°C)

Now, we have pKa, which is equal to -log Ka. Let us calculate pKa:

pKa = - log(1.8 x 10⁻⁵)

pKa = 4.74

pKw = 14

pKb = pKw - pKa = 14 - 4.74 = 9.26

Let us now use the formula for Kb:

Kb = [BH⁺][OH⁻] / [B]

Kb = [CH3CH2NH3⁺][OH⁻] / [CH3CH2NH2]

Let us represent [CH3CH2NH3⁺] as x and [OH⁻] as y.

Let [CH3CH2NH2] be 0.75-x.

Therefore, we have:

[CH3CH2NH3⁺][OH⁻] / [CH3CH2NH2] = 7.1 x 10⁻⁴x

y / (0.75-x) = 7.1 x 10⁻⁴

y = [OH⁻]

pOH = -log [OH⁻]

pOH = -log (3.53 x 10⁻³)

The pOH is 2.45.Using the formula

pH + pOH = pKw:

2.92 + 2.45 = 14 - pH + pOH2.

92 + 2.45 = 14 - pH + 11.559.37 - 11.55 = pH

pH = - log(1.93 x 10⁻¹⁴)

The pH is 13.71

C) The hydronium ion concentrations can be represented as [H3O+]. In a 0.75 M acetic acid solution:

[H3O+] = 1.21 x 10⁻³

In a 0.75 M diethylamine solution:

[H3O+] = 1.93 x 10⁻¹⁴

The ratio of the hydronium ion concentrations in each solution is:

1.93 x 10⁻¹⁴ / 1.21 x 10⁻³ = 1.59 x 10⁻¹¹.

Therefore, the ratio of the hydronium ion concentrations in each solution is 1.59 x 10⁻¹¹.

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The 3 types of organic molecules, including their "building" blocks and in which types of food, are found as they relate to the growth of the organism and the release of energy within the organ are carbohydrates, proteins, and lipids.

Carbohydrates are made of monosaccharides, or simple sugars, such as glucose and fructose, they are found in foods like fruits, vegetables, and grains. Carbohydrates provide organisms with energy for growth and daily activities, and they serve as a source of stored energy in the form of glycogen or starch. Proteins are composed of amino acids, which are the building blocks for creating various proteins in organisms. Proteins are found in foods like meat, poultry, fish, eggs, and beans, they play a crucial role in the growth and repair of tissues and are essential for various processes like enzyme production, hormone regulation, and immune function.

Lipids, such as fats and oils, are made of glycerol and fatty acids, they are found in foods like nuts, seeds, and avocados, as well as animal fats. Lipids serve as long-term energy storage, provide insulation, and contribute to cell membrane structure in organisms. In summary, carbohydrates, proteins, and lipids are the three main types of organic molecules that contribute to organism growth and energy release. Each type is composed of unique building blocks and can be found in various foods.

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The range for the target ph of a buffer solution that would favours ph stabilization unders this condition in (4.75-4.85).

What is Henderson Hasselback equation ?

The Henderson-Hasselbalch equation, pH = pKa + log([A]/[HA]), can be used to determine the pH of a buffer. The terms "HA" and "A" in this equation stand for the equilibrium concentrations of the conjugate acid-base pair that were employed to make the buffer solution.

What is acetate?

A proton is taken out of the carboxy group of acetic acid to produce acetate, a monocarboxylic acid anion. It performs a function as a Saccharomyces cerevisiae metabolite as well as a human metabolite. The base is a conjugate of an acetic acid. ChEBI. Alternatives to ACETIC ACID

The Henderson Hasselback equation for a suitable acetic acid / acetate buffer-

Ph= Pka + log (salt)/(acid)

(salt) = (acetate)

(acid) = (acetic acid)

now, CH3 COOH dissociates as

CH3COOH ⇔ CH3COOH +H

Pka for CH3COOH = 4.75

If a chemical reaction produced hydroxide ions, then CH3COOH gets consumed and more acetate ions with produces. This leads to change in Ph of the solution as due (CH3C00H-) increases the ph absence increases.

The range for the target ph of a buffer solution that would favours ph stabilization unders this condition in (4.75-4.85)

The buffer capacity is the ability of a given buffer to resist any changes in ph when small amount of acid or base added to it.The buffer capacity of a mixed weak acid( here Acetic acid)-base (NaOH) buffer is much greater when the individual pKa values are in close proximity with each other.

Therefore, The range for the target ph of a buffer solution that would favours ph stabilization unders this condition in (4.75-4.85).

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An acid base reaction always produces salt and water.

In neutralization reaction, an acid and a base react together to produce salt and water.

In this chemical reaction hydrogen ions (H+ ions) come form an acid while hydroxide ions (OH- ions) are released by a base which combine together to form water.

For example, let's take the reaction between sodium hydroxide and hydrochloric acid.

NaOH + HCl -------> NaCl + H2O

the above reaction produces sodium chloride salt and water.

Overall, it is a neutral reaction because no excess ions are left behind in the solution.

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Of the following correctly predicts the most likely mode of radioactive decay for the nuclide \(As^{33}_{84}\)

The nuclide \(As^{33}_{84}\) has an atomic number of 33, indicating that it is arsenic. To predict the most likely mode of radioactive decay for \(As^{33}_{84}\), we need to consider its position on the periodic table and the stability of its nucleus

\(As^{33}_{84}\) falls into the category of a stable nuclide since it has a stable atomic number. Stable nuclides do not undergo radioactive decay. Therefore, it is unlikely that \(As^{33}_{84}\) would undergo spontaneous radioactive decay through alpha decay (emitting an alpha particle), beta decay (emitting a beta particle), or gamma decay (emitting gamma radiation). Nuclides that are unstable and undergo radioactive decay typically have atomic numbers higher than the stable region of the periodic table or have an imbalance of protons and neutrons in the nucleus. However, as \(As^{33}_{84}\) is a stable nuclide, it is not expected to undergo any form of radioactive decay. Hence, the most likely mode of radioactive decay for the nuclie \(As^{33}_{84}\) is no decay at all since it is a stable nuclide.

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Answer:

1.1 x 10⁴ J

Explanation:

To calculate eth energy needed, you need to use the following equation:

Q = mcΔT

In this equation,

-----> Q = energy/heat (J)

-----> m = mass (g)

-----> c = specific heat (4.184 J/g°C)

-----> ΔT = change in temperature (°C)

You can plug the given values into the equation and solve.

Q = mcΔT

Q = (75.0 g)(4.184 J/g°C)(55.0 °C - 20.0 °C)

Q = (75.0 g)(4.184 J/g°C)(35.0)

Q = 11,000 J

Q = 1.1 x 10⁴ J

The pH of the gastric juice is approximately 1.08.

To determine the pH of the gastric juice, we need to calculate the concentration of H+ ions in the solution. Since the gastric juice was titrated with NaOH to neutrality, the moles of H+ ions in the gastric juice should be equal to the moles of OH- ions added by NaOH.

Given that 7.2 mL of 0.1 M NaOH was required to reach neutrality, we can calculate the moles of OH- ions added:

Moles of OH- ions = Volume of NaOH (L) * Concentration of NaOH (mol/L)

Moles of OH- ions = 7.2 mL * (0.1 mol/L / 1000 mL/L)

Moles of OH- ions = 0.0072 mol

Since the H+ and OH- ions react in a 1:1 ratio, the moles of H+ ions in the gastric juice are also 0.0072 mol.

The volume of the gastric juice sample used was 10.0 mL, which is equivalent to 0.010 L.

Now we can calculate the concentration of H+ ions in the gastric juice:

Concentration of H+ ions = Moles of H+ ions / Volume of gastric juice (L)

Concentration of H+ ions = 0.0072 mol / 0.010 L

Concentration of H+ ions = 0.72 mol/L

To find the pH, we can use the formula: pH = -log[H+]

pH = -log(0.72)

pH ≈ 1.08

The pH of the gastric juice, as determined from the titration with NaOH, is approximately 1.08. This indicates a highly acidic environment in the stomach.

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The ion described by 38 protons, 38 neutrons, and 36 electrons is likely to be a calcium ion, Ca2+. Calcium has an atomic number of 20, meaning it has 20 protons, and therefore 20 electrons in a neutral atom.

If it has gained two electrons, it will have 22 electrons, and a charge of 2-, which matches the description of a Ca2+ ion.

Calcium is an important element in the human body and the environment. It is essential for strong bones and teeth, healthy blood clotting, and nerve function.

Calcium is also involved in many other biological processes, such as muscle contraction and the regulation of heart rate. In the environment, calcium is found in rocks, such as limestone and marble, and is an important component of soil.

Calcium compounds are used in a variety of industrial applications, such as the production of cement, glass, and paper.

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It is accurate to say that Kentucky bluegrass is more heat-resistant than annual bluegrass.

All the cool-season grasses typical of northern lawns offer some degree of cold endurance, but Kentucky bluegrass is the most resilient, enduring the bitter winter temperatures. Excellent cold tolerance is another quality of fine fescue. Compared to Kentucky bluegrass, creeping bentgrass is more resistant to submersion. In general, cool-season turfgrasses are more tolerant to shade than warm-season turfgrasses. The Augustinegrass is the most tolerant of shade. Of all maintained turfgrasses, bermudagrass requires the most light, followed by carpetgrass, bahiagrass, zoysiagrass, centipedegrass, Kentucky bluegrass, tall fescue, and red fescue. Although centipedegrass is marginally more cold tolerant than St. Augustine grass, prolonged exposure to temperatures of 5°F or lower can cause centipedegrass to die.

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Answer:

Explanation:

Carbon cycle explains the movement of carbon between the earth's biosphere, geosphere, hydrosphere and atmosphere. ... Carbon atoms are then released as carbon dioxide when organisms respire. The formation of fossil fuels and sedimentary rocks contribute to the carbon cycle for very long periods.

Explanation:

Corrosion of iron is called as rusting. Rusting is oxidation of iron in the presence of oxygen and water and leads to formation of hydrated ferric oxide.

Methods to prevent rusting are :

1. Application of paint: It prevents the direct exposure of metal to atmosphere.

2. Application of oils or grease: It creates a barrier between the metal and atmosphere.

3. Galvanization : It is coating of iron with more active metal zinc so that zinc gets oxidized and protects iron.

4. Cathodic protection : It involves connecting iron to a more active metal which loses electrons on behalf of iron and thus protects iron by rendering it as cathode.

5. Coating with wax tapes: It prevents the direct exposure of metal to atmosphere.

The molar mass of magnesium is 24g/mol. The mass with one mole of a chemical in grams is known as its molar mass.

The mass with one mole of a chemical in grams is known as its molar mass and molecular mass. The term can also mean "mass per mole." The total mass of the atoms in one mole of a material is its molar mass.

Grams/mol is the measurement of molar mass. A mole of any material (atoms, molecules, etc.) has a standard value of 6.023 1023 units, which is the unit used as a reference in chemistry. It is sometimes referred to as Avogadro's number and is denoted by the symbol NA. A key formula inside the mole notion is molar mass. The molar mass of magnesium is 24g/mol.

Therefore, the molar mass of magnesium is 24g/mol.

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Answer:

Explanation:

Cellular respiration does not depend on light...  Some plants may go into a form of hibernation during winter when the amount of light during the day is less.  The reduction of plant growth and activity would reduce the need for the energy produced by cellular respiration.

Explanation:

Balance between K+ charge and Br- charge = 0

The polar tundra (ET) climate zone is characterized by average monthly temperatures that exceed 0°C (32°F) but remain below 10°C (50°F).

This climate zone is typically found in the Arctic regions, including parts of Alaska, Canada, Greenland, and Siberia. The polar tundra experiences long, harsh winters with temperatures well below freezing, while summers are short and cool.

The subpolar (Dfc) climate zone is colder and experiences average monthly temperatures that generally fall below freezing throughout the year. It is typically found in areas closer to the poles, such as parts of Alaska, northern Canada, and Siberia.

The alpine (An) climate zone refers to high-altitude areas, usually found in mountainous regions above the tree line. These areas can have cold temperatures throughout the year, and the average monthly temperatures may exceed 0°C (32°F) but generally remain below 10°C (50°F).

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A catalyst is a substance that speeds up a chemical reaction and is also consumed during the reaction.

A catalyst is a substance that increases the rate of a chemical reaction by providing an alternative reaction pathway with lower activation energy. It accomplishes this by facilitating the formation of intermediate species and reducing the energy barrier for the reaction to occur. The catalyst itself undergoes a reaction with the reactants, forming an intermediate complex, but it is regenerated and recovered in its original form at the end of the reaction.

The role of a catalyst can be explained through a simplified reaction mechanism. Consider a hypothetical reaction between reactants A and B to form product C. Without a catalyst, the reaction may proceed slowly due to a high activation energy. However, when a catalyst is introduced, it provides an alternative pathway with a lower activation energy.

The catalyst initially binds to the reactants, forming a catalyst-reactant complex. This complex undergoes rearrangements and reactions that lead to the formation of the product. At the end of the reaction, the catalyst is regenerated, allowing it to participate in subsequent reaction cycles.

The consumption of the catalyst occurs during the reaction, as it reacts with the reactants to form intermediates and ultimately the products. However, the catalyst is not permanently altered or consumed entirely. Instead, it is regenerated and can be reused in subsequent reactions.

In summary, a catalyst is a substance that accelerates a chemical reaction by providing an alternative reaction pathway with lower activation energy. It is consumed during the reaction as it reacts with the reactants to form intermediates and products. However, the catalyst is not permanently consumed and can be regenerated for reuse in subsequent reactions.

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