Which of the following statements is true of the internal energy of a system and its surroundings during an energy exchange with a negative ∆Esys?

a. The internal energy of the system and the surroundings increases

b. The internal energy of the system and the surroundings decreases.

c. The internal energy of the system increases and the surroundings decreases.

d. The internal energy of the system decreases and the surroundings increases.

Answer:

This one also it is opposite of endothermic reaction

Answer:

hey are the results of many experiments over a long period of time.

Explanation:

Answer:

Ni(NO3)2 is the limiting reactant.

Explanation:

- First, we balance the equation...

Ni(NO3)2 + 2 KOH --->  2 KNO3 + Ni(OH)2

- Second, we find the moles of each substance...

65g Ni(NO3)2 / 182.703g Ni(NO3)2 = 0.356 mol Ni(NO3)2

58g KOH / 56.1056g KOH = 1.034 mol KOH

- Third, to make the molar ratio equal to each other for comparison, we either multiply KOH by 1/2 or multiply Ni(NO3)2 by 2 to compare the number of moles; because the Ni(NO3)2 to KOH molar ratio is 1 to 2. Note that the multiplication of moles is only for comparison. We do not use these multiplied values. We use the values from step 2...

0.356 mol Ni(NO3)2 * 2 = 0.712 mol Ni(NO3)2

0.712 mol Ni(NO3)2 < 1.034 mol KOH ... Ni(NO3)2 is the limiting reactant.

Approximately 631.5 liters of dry air at 25°C and 750 torr would need to be processed to produce 150 liters of liquid \(O_2\) -183°C.

To solve this problem, we need to consider the ideal gas law and the molar volume of gases.

First, we can calculate the number of moles of oxygen in 150 L of liquid \(O_2\) at -183°C. To do this, we divide the mass of liquid oxygen by its molar mass:

Mass of liquid oxygen = volume of liquid oxygen * density of liquid oxygen = 150 L * 1.14 g/mL = 171 g

Molar mass of oxygen (O2) = 32 g/mol

Number of moles of oxygen = mass of oxygen / molar mass of oxygen = 171 g / 32 g/mol ≈ 5.34 mol

Since the mole fraction of oxygen in dry air is given as 0.21, we can calculate the total moles of dry air needed to produce 5.34 mol of oxygen:

Moles of dry air = moles of oxygen / mole fraction of oxygen = 5.34 mol / 0.21 ≈ 25.43 mol

Now, we can use the ideal gas law to calculate the volume of dry air at 25°C and 750 torr (convert to atm) that corresponds to 25.43 mol:

PV = nRT

P = 750 torr * (1 atm / 760 torr) ≈ 0.987 atm

V = volume of dry air (unknown)

n = 25.43 mol

R = 0.0821 L·atm/(mol·K)

T = 25°C + 273.15 = 298.15 K

Solving for V:

V = nRT / P = (25.43 mol)(0.0821 L·atm/(mol·K))(298.15 K) / 0.987 atm ≈ 631.5 L

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answer

the mole should be considered as an SI unit because this quantity is used to determine many other units of measure such as Liters for volume, the pressure of a system in pascals. it is useful in all chemical studies

The balanced chemical equation for the decomposition of aspirin (acetylsalicylic acid) is:

\(2C_{9}H_{8}O_{4} (aspirin) → 2C_{7}H_{6}O_{3} (salicylic acid) + 2CO_{2} (Carbon dioxide) + H_{2}O (water)\)

In this reaction, the aspirin molecule breaks down into salicylic acid, carbon dioxide, and water. The reaction is typically catalyzed by heat or exposure to acidic or basic conditions.

Aspirin, or acetylsalicylic acid, contains ester functional groups that can undergo hydrolysis. Under suitable conditions, the ester bond in aspirin is cleaved, leading to the formation of salicylic acid, which is the primary decomposition product. Additionally, carbon dioxide and water are released as byproducts of the reaction.

The balanced equation shows that for every two molecules of aspirin, two molecules of salicylic acid, two molecules of carbon dioxide, and one molecule of water are formed. Understanding the decomposition of aspirin is important in pharmaceutical and chemical industries to ensure the stability and shelf-life of the compound, as well as to study its breakdown products and potential side reactions.

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Answer:

The ratio between the molecules dissolved in the solution (n = NaCl/KCl) is approximately 1.28.

Explanation:

To calculate the ratio between the molecules dissolved in the solution, we first need to determine the number of moles of each substance that is dissolved in the solution.

For KCl:

Molar mass of KCl = 39.1 g/mol (potassium) + 35.5 g/mol (chlorine) = 74.6 g/mol

Number of moles of KCl = mass of KCl / molar mass of KCl = 1 g / 74.6 g/mol = 0.0134 mol

For NaCl:

Molar mass of NaCl = 22.99 g/mol (sodium) + 35.5 g/mol (chlorine) = 58.5 g/mol

Number of moles of NaCl = mass of NaCl / molar mass of NaCl = 1 g / 58.5 g/mol = 0.0171 mol

The ratio between the molecules dissolved in the solution (n = NaCl/KCl) can be calculated by dividing the number of moles of NaCl by the number of moles of KCl:

n = 0.0171 mol / 0.0134 mol = 1.28

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.

The density of ammonia gas in the 6.0 L container at a pressure of 820 mm Hg is approximately 0.805 g/L.

To determine the density of ammonia gas (NH3) in a 6.0 L container at a pressure of 820 mm Hg, we need to use the ideal gas law equation, which relates pressure, volume, number of moles, and temperature for a given gas.

The ideal gas law equation is:

PV = nRT

Where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

Since we are given the pressure (820 mm Hg), volume (6.0 L), and assuming standard temperature and pressure (STP), we can use the values for R (0.0821 L·atm/(mol·K)) and convert the pressure to atm by dividing by 760 (1 atm = 760 mm Hg).

820 mm Hg / 760 mm Hg/atm = 1.08 atm

Now we can rearrange the ideal gas law equation to solve for density (d):

d = (P * M) / (RT)

Where M is the molar mass of ammonia (NH3), which is approximately 17.03 g/mol.

Substituting the values, we have:

d = (1.08 atm * 17.03 g/mol) / (0.0821 L·atm/(mol·K) * 298 K)

Simplifying the equation, we find:

d ≈ 0.805 g/L

Therefore, the density of ammonia gas in the 6.0 L container at a pressure of 820 mm Hg is approximately 0.805 g/L.

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Answer:

If you left a block of dry ice in a bow of room temperature all day, it would evaporate.dry ice undergo sublimation,it will go from solid to gas instead of going through the normal process

solid-liquid- gas

To kill bacteria, chlorine is added to the water. However, it does not function immediately away and kill CDC.

Thus, When handled correctly, free chlorine* can destroy the majority of bacteria in a matter of minutes.

The CDC advises maintaining a pH of 7.2–7.8 and free chlorine levels of at least 1 ppm in swimming pools and 3 ppm in hot tubs and spas.

The CDC advises a pH of 7.2–7.8 and a free accessible chlorine content of at least 2 ppm in swimming pools when using cyanuric acid, a chlorine stabilizer, or chlorine products containing cyanuric acid (for instance, products generally known as dichlor or trichlor. The CDC advises against using cyanuric acid or chlorine products containing it in hot tubs or spas.

Thus, To kill bacteria, chlorine is added to the water. However, it does not function immediately away and kill CDC.

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The highlighted apparatus are;

1) stirring rod

2) crucible

The term chemical reaction refers to the process by which two or more substances are combined to form a product. The product may look like or different from the reactants that were combined to produce it.

Now we can see the set up that was used as shown for the reaction of  dilute nitric acid with lead(II) oxide to prepare lead(II) nitrate.

The highlighted apparatus are;

1) stirring rod

2) crucible

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Answer:

The reaction would shift toward the reactants

When the reaction reach equilibrium the partial pressure of NH3 will be greater than 1atm

Explanation:

For the reaction:

2NH₃(g) ⇄ N₂(g) + 3H₂(g)

Where K is defined as:

\(K = \frac{P_{N_{2}}*P_{H_2}^3}{P_{NH_3}^2} = 0.83\)

As initial pressures of all 3 gases is 1.0atm, reaction quotient, Q, is:

\(Q = \frac{1atm*{1atm}^3}{1atm^2} = 1\)

As Q > K, the reaction will produce more NH₃ until Q = K consuming N₂ and H₂.

Thus, there are true:

Answer:

Explanation:

i) in keeping industrial machine cool

ii) in textile inustries for dying clothes

The number of moles of the sodium chlroide from the calculation is 0.11 moles.

We can connect a substance's mass to its particle count using the concept of a mole. A material's molar mass, which is measured in grams per mole, is the mass of one mole of that substance. One mole of carbon-12 atoms, for instance, weighs 12 grams according to its molar mass of 12 grams/mol.

We have that;

Number of moles = Mass/molar mass

mass = 6.37 grams

Molar mass =  58.5 g/mol

Number of moles = 6.37 g/58.5 g/mol

= 0.11 moles

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Answer:

When the gas is compressed, its molecules come closer and internal energy of gas is increased and the number of collisions will also increase. As the gas is compressed, the work done on it shows up as increased internal energy, which must be transferred to the surroundings to keep the temperature constant.

Human impact on the environment is often more dramatic than the impact

of most other living things because humans have a greater ability to alter

the environment​.

Human beings are usually in control of most of the resources on earth such

as plants, animals, etc. Humans have developed new technologies for doing

things which have an impact on the environment.

Deforestation, burning of fossil fuel in automobiles and industries emits toxic

gases which have been found to alter the environment more than other

living things.

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A  chemical change is said to occur when there is the appearance of a new substance after the reaction.

We know that a chemical change is said to occur when there is the appearance of a new substance after the reaction. This can be signaled by the appearance of a solid or gas as well as a change in color.

Now what has happened here is a chemical reaction that took place as follows;

2Mg(s) + O2(g) ------> 2MgO(s)

The burning of magnesium gives off a silvery white emission spectrum. The reaction that occurs is a combustion reaction and a new substance, MgO was formed.

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Answer:

98.08 g/mol

Explanation:

Hope this helps.

Solution :

For the reaction given :

\($\text{2Hg}_{(l)}+\text{O}_2_{(g)} \rightarrow \text{2HgO}_{(s)}$\)

Thus we know that the equilibrium constant \($K_c$\) contains aqueous an dgas species only.

∴       \($K_c=\frac{1}{[O_2]}$\)    ............(1)

Now at the equilibrium, an amount of the 13.4 g of oxygen was found in the vessel of 6.9 liters. For determining the concentration of the oxygen gas, we use :

\($[O_2]= \frac{n_{O_2}}{V_{soln}}$\)  ...................  (2)

Here, \($n_{O_2}$\) = no. of moles of oxygen gas (mol)

         \($V_{soln}$\) = volume of solution (L)

Therefore the number of moles of the oxygen gas is calculated by directly using the molecular weight (31.9988 g/mol) as the conversion factor.

∴      \($n_{O_2}= 13.4 \ g \times \frac{\text{1 mol}}{31.9988 \ g}$\)

              = 0.418 mol

Now substituting the known values in (2), we can find the equilibrium concentration of the oxygen gas :

\($[O_2] =\frac{0.418 \ \text{mol}}{6.9 \ \text{L}}$\)

     = 0.0605 M

Therefore substituting the result in (1), the equilibrium constant for the reaction is :

\($K_c=\frac{1}{0.0605}$\)

    = 16.52

Answer:

Answer : A metal atom loses electrons from its outermost energy level and acquires a Positive Charge. These electrons join a nonmetal atom. The ionic compound formed because of this transfer of electrons is electrically Neutral.

Explanation or losing electrons. For metals, the number of valence electrons are less and it is easier to lose these electrons.

When electrons are lost, the number of protons become more than the electrons. This creates an excess of positive charge. As a result the species becomes positively charged and is known as cation.

During formation of ionic bond, metals always form a positive ion (cation) by losing electrons. These electrons are accepted by the nonmetals and they become negatively charged. A negatively charged ion is known as anion and nonmetals always form an anion.

These are attracted to each other due to the opposite charges present on them. In an ionic compound they balance the charges on each other making the compound neutral.

From the above discussion, we can fill in the blanks as follows.

A metal atom loses electrons from its outermost energy level and acquires a Positive Charge. These electrons join a nonmetal atom. The ionic compound formed because of this transfer of electrons is electrically Neutral.

Answer:

Option D

Explanation:

The switch safely opens and closes the circuit

Answer:

orbital shape.

Explanation:

1) There are four quantum numbers to describe the electrons. These are:

i) Principal quantum number (n)

ii) Azimuthal quantum number (ℓ), also called angular momentum quantum number.

iii) Magnetic quantum number (m)

iv) Spin quantum number (s)

2) The principal quantum number tells the main energy level. It can be 1, 2, 3, 4, 5, 6, 7. It is related to the orbital size. 1 is a small orbital, 7 is a big orbital.

2) The Azimuthal quantum number (ℓ) or angular momentum quantum number may be a number between 0 and n - 1.

It tells the kind of orbital, which is its shape

The correspondence is:

0 = s orbital,

1 = p orbital,

2 = d orbital,

3 = f orbital.

3) Magnetic quantum number (m) tells the orientation. It can be from - ℓ to + ℓ

For example when ℓ = 1, the orbital is p, and the magnetic quantum number may be -1, 0, or +1, which corresponds to px, py, pz: the orientation of the p orbital in the space.

4) Spin quantum number (s) can be either +1/2 or -1/2.

JM~ Hope this helps you out

Answer:

B/Ti

Explanation:

Answer:

the answer is B

Explanation:

Answer:

A satellite may be malfunctioning.

Line of sight may be blocked.

low batteries in your GPS.