Calculate the heat change in kilojoules for condensation of 195 g of steam at 100 ° C

Answer:

A - Atom ---> molecule or compound.

A 200 g sample including calcium (Ca), reacts with the excess of hydrochloric acid.  If 4 g of hydrogen gas (H2) is produced, 36.3% is mass percent of calcium of sample.

The term mass percent is sometimes referred to as weight percent or w/w%. The total mass of every one of the atoms in a mole that makes up the compound is the molar mass. The total of all the individual percentages ought to equal 100 percent.

Check the last important number for rounding errors to ensure that the percentage add up. The relative amounts of the components in a compound of chemicals are described by their mass percent composition. Mass composition in percent is also referred to as mass percent. The symbol for it is w/w%.

Ca + HCl → CaCl\(_2\)+ H\(_2\)

moles of calcium = 200/ 40= 5 moles

moles of CaCl\(_2\) = 5moles

mass of CaCl\(_2\) = 5× 110.98= 550g

mass % of Ca = (200/550g )×  100=36.3%

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Answer:

D

Explanation:

if there is more dark soot, then there is more of a chance that they won't be seen

Answer:

D

Explanation:

Peppered moths were originally more white in coloring due to needing to be able to blend into the trees. But during the industrial revolution, more smog and soot was being produced, causing the trees to become more black in color, making it harder for the moths to blend in. Therefore, resulting in the need for genetic mutations within the moths to help them better blend into their surroundings to avoid predators. (I just recently took this test too)

Hope this helps :)

answer

chemical equation for the reaction of sulfur dioxide (SO2) with carbon monoxide (CO) is:

SO2 + 2CO → CO2 + S

number of moles of SO2 required to produce 118.0 mol CO can be calculated:

1 mole SO2 reacts with 2 moles CO

x moles SO2 reacts with 118.0 mol CO

x = (1/2) × 118.0 mol CO

x = 59.0 mol SO2

59.0 moles of SO2 are required to produce 118.0 mol CO

Answer: B

Explanation: Formaldehyde molecules do not form an extended structure and can freely move past each other

The pressure of the environment affects the liquid's boiling point. The boiling point of the liquid is higher when it is under high pressure than when it is under normal atmospheric pressure. For a given pressure, various liquids have different boiling points.

The temperature at which a liquid's vapour pressure equals the surrounding atmosphere is known as the boiling point of the liquid. This temperature causes the liquid to become a vapour.

The temperature of the liquid, the pressure of the atmosphere, and the pressure of the vapour all affect its boiling point.

We know that change in temperature of a system is given by the following formula:

Initial boiling point (T₁) = 80.1 °C

ΔT = T₂ - T₁

2.25 = T₂ - 80.1

T₂ = 82.35  °C

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Answer:

82.35

Explanation:

acellus

Answer: K = 8.01 ·10^-3 M

Explanation:   K = [NO2] ² / [N2O4] = (0.0141 M)² / 0.0248 M = 0.00801 M

There are approximately \(2.76 * 10^{24\) ammonia molecules in the given sample.

To calculate the number of ammonia molecules in the sample, we need to use Avogadro's number and the molar mass of ammonia.

The molar mass of ammonia \((NH_3)\) can be calculated by adding up the atomic masses of nitrogen (N) and hydrogen (H):

Molar mass of \(NH_3\) = (1 x atomic mass of N) + (3 x atomic mass of H)

              = (1 x 14.01 g/mol) + (3 x 1.01 g/mol)

              = 14.01 g/mol + 3.03 g/mol

              = 17.04 g/mol

Now, we can calculate the number of moles of ammonia in the sample using the formula:

Number of moles = Mass of the sample / Molar mass

Number of moles = 78.25 g / 17.04 g/mol

              ≈ 4.5865 mol (rounded to four decimal places)

Finally, we can use Avogadro's number, which represents the number of particles (atoms, molecules, etc.) in one mole of a substance. Avogadro's number is approximately \(6.022 * 10^{23\) particles/mol.

Number of ammonia molecules = Number of moles x Avogadro's number

Number of ammonia molecules ≈ 4.5865 mol x (\(6.022 * 10^{23\) molecules/mol)

                           ≈ \(2.76 * 10^{24\) molecules (rounded to two significant figures)

Therefore, the provided sample contains roughly \(2.76 * 10^{24\) ammonia molecules.

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The number of ammonia molecules in the sample is approximately 2.764 x \(10^{24}\) molecules.

To calculate the number of ammonia molecules in a given sample, we need to use Avogadro's number and the molar mass of ammonia.

The molar mass of ammonia (NH3) is calculated as follows:

Molar mass of N = 14.01 g/mol

Molar mass of H = 1.01 g/mol

Total molar mass of NH3 = 14.01 g/mol + (3 * 1.01 g/mol) = 17.03 g/mol

Now, we can calculate the number of moles of ammonia in the sample:

Number of moles = Mass of sample / Molar mass of NH3

Number of moles = 78.25 g / 17.03 g/mol = 4.594 moles

Next, we use Avogadro's number, which states that there are 6.022 x \(10^{23}\) molecules in one mole of a substance.

Number of molecules = Number of moles * Avogadro's number

Number of molecules = 4.594 moles * 6.022 x \(10^{23}\) molecules/mol = 2.764 x \(10^{24}\) molecules

Therefore, there are approximately 2.764 x \(10^{24}\) ammonia molecules in the given sample of 78.25 g.

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You would recover 36.525g of NaCl after evaporating all of the water.

To find the grams of NaCl that would be recovered after evaporating all the water, we can use the following formula:

mass = moles * molar mass

Where:

Moles = Molarity * Volume

Molarity = 0.250 M

Volume = 2500.0 mL = 2.5 L

Molar mass of NaCl = 58.44 g/mol

mass = 0.250 M * 2.5 L * 58.44 g/mol

mass = 36.525 g

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To dilute a solution of sodium chloride (NaCl), we can use the following methods: Add more water to the solution and Remove a small amount of the solution and mix it with water.

By adding water, you increase the overall volume of the solution, which effectively reduces the concentration of NaCl. This is the most common and straightforward method of dilution.

By taking out a portion of the concentrated solution and mixing it with water, you decrease the concentration of NaCl in that portion, resulting in overall dilution when you combine it back with the rest of the solution.

By heating the solution, you cause the water to evaporate, leaving behind a more concentrated solution of NaCl. This process does not dilute the solution but rather concentrates it further.

Adding more NaCl to the solution would actually increase the concentration, not dilute it. Therefore, it is not a valid method for dilution.

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Answer:

have similar properties

Explanation:

Elements in a column of the periodic table have similar chemical properties.

A periodic column is also called a group or family.

Elements in the same group has the same number of valence electrons.

Therefore, they will combine chemically the same way.

This is not so for the periods on the periodic table.

Answer:

295 mL

Explanation:

Given data:

Volume needed = ?

Molarity of solution = 0.193 M

Mass of salt = 7.90 g

Solution:

Molarity =  number of moles of solute / volume in L

Number of moles of salt = mass/molar mass

Number of moles of salt = 7.90 g/ 138.205 g/mol

Number of moles = 0.057 mol

Volume needed:

Molarity = number of moles / volume in L

0.193 M = 0.057 mol / volume in L

Volume in L = 0.057 mol /  0.193 M

Volume in L = 0.295 L

L into mL

0.295 L × 1000 mL/1L

295 mL

Answer: d

Explanation:because it makes sence i think

Answer:

i think its c

Explanation:

Answer:

Explanation:

The product formed will be alkaline solution of potassium hydroxide .

K₂O + H₂O = 2 KOH .

Therefore  K₂O is called basic oxide .

Answer:

it is directly proportional to the temperature of the gas

Explanation:

Answer:

not sure if this us right but oxygen and fluorine? I learned chem but I forgot about it kinda sorry

Answer:

This movement releases energy and generates seismic waves that can be recorded by specialized instruments used by scientists. The point on a fault at which the first movement or break occurs during an earthquake is called the earthquake's hypocenter

Explanation:

The number of moles of cesium chloride produced 0.183 moles.

The number of moles of a substance can be calculated by dividing the mass of the substance by its molar mass.

According to this question, the chemical formula for cesium chloride is CsCl. A chemist measured the amount of cesium chloride produced during an experiment. She finds that 30.8 g of cesium chloride is produced.

The molar mass of Cesium chloride is 168.36 g/mol

Moles = 30.8g ÷ 168.36g/lol

moles = 0.183 moles

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This problem is asking for an explanation of what happens when an ionic bond is formed. Although the choices are not given in the question, one can find them on the attached file and realize the answer is C "a less electronegative atom donates an electron to a more electronegative atom" according to:

In chemistry, the forces that hold atoms together are known as chemical bonds and act like connections for atoms to form compounds. There exist ionic and covalent bonds, so the formers occur when electrons are thoroughly donated from the least electronegative atom to the most electronegative one.

On the flip side, covalent bonds occur when the electrons are shared between the two or more of the atoms forming the compound. In such a way, one can discard choices A and B because they are more related to covalent bonds.

Therefore, one can select C "a less electronegative atom donates an electron to a more electronegative atom" as the correct answer, because not all the elements are able to donate more than one single electron, and the less its valency, the more ionic the compound turns out to be.

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The model would be complete when there two pairs of white dots and one pair of black dots

The chemical process of electrolysis breaks down water molecules into their component parts, hydrogen  and oxygen , using an electric current. Two simultaneous reactions take place at distinct electrodes, referred to as the anode and cathode, which are submerged in an electrolyte solution, to produce this process.

A crucial step in the process of creating hydrogen gas, a clean and renewable energy source, is the electrolysis of water.

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Answer:

When conducting a chemistry lab experiment using chalk (calcium carbonate) in vinegar (acetic acid), there are several limitations and precautions to be aware of:

Limitations of chalk in vinegar chemistry experiment:

Reaction rate: The reaction between chalk and vinegar is relatively slow, which may require a longer observation period or higher concentration of vinegar to observe significant changes within a reasonable time frame.

Solubility: Chalk may not dissolve completely in vinegar, resulting in incomplete reaction or difficulty in obtaining accurate results.

Product formation: The reaction between chalk and vinegar produces carbon dioxide gas, water, and calcium acetate. The carbon dioxide gas may escape into the atmosphere, leading to loss of product and inaccurate measurements.

pH: Chalk is a basic substance, and the reaction with vinegar, which is acidic, may result in neutralization, leading to a decrease in the overall acidity of the reaction mixture.

Precautions to take in chalk in vinegar chemistry experiment:

Ventilation: The reaction between chalk and vinegar produces carbon dioxide gas, which can displace air and potentially cause asphyxiation in a closed or poorly ventilated area. Conduct the experiment in a well-ventilated area or under a fume hood to ensure adequate air circulation.

Eye and skin protection: Vinegar is an acid and can cause skin and eye irritation. Wear appropriate personal protective equipment (PPE), such as gloves and goggles, to protect yourself from contact with vinegar or any other chemicals used in the experiment.

Chemical handling: Handle the chemicals, including chalk and vinegar, with care, following proper lab safety protocols. Avoid ingestion, inhalation, or direct contact with the chemicals, and dispose of them properly according to local regulations.

Accuracy in measurements: Use calibrated and accurate measuring tools, such as graduated cylinders or burettes, to measure the amount of chalk, vinegar, and other reagents accurately. This will ensure the reliability and accuracy of the experimental results.

Observations: Make careful and detailed observations during the experiment, noting any changes in appearance, gas evolution, or other relevant observations. Take measurements at appropriate intervals and record the data accurately for analysis and interpretation.

It is important to follow good laboratory practices, including proper chemical handling, accurate measurements, and cautious observations, to ensure safe and reliable results in a chalk in vinegar chemistry lab experiment. Consult with a qualified instructor or supervisor for specific guidelines and precautions related to your experiment.

Answer: An atom is the sub-component of a molecule, or the smallest unit of matter. It is the smallest part an element can divide into. A molecule is made up of atoms that are bound by ionic, covalent or metallic bond.

Answer:

veryy help ful

Explanation:

An atom is the sub-component of a molecule, or the smallest unit of matter. It is the smallest part an element can divide into. A molecule is made up of atoms that are bound by ionic, covalent or metallic bond.

Water is compound with chemical symbol H2O. Water is made up of hydrogen and oxygen atom. The presence of the -OH bond in its structure makes it a polar molecule.

It is therefore called universal solvent due to its polar nature and ability to form hydrogen bonds with other molecules. Water is also a universal solvent because substance dissolves easily in it than other chemicals.

The presence of partial positive charges on the hydrogens and a partial negative charge on the oxygen makes it easier to interact with other materials.

Answer:

ty

Explanation:

your question is invalid

Answer:

The answer you are looking for is A