Balance the following equations:

__CuS2 + HNO3 →

__Cu(NO3)2 + __H2SO4 +

__N2O + ___H20

Answer:

66

Explanation:

The number of neutrons is the atomic number (25) subtracted from the mass (91). So, 91 - 25 = 66.

Answer:

Prokaryotes have no cell nucleus and no membrane enclosed organelles. Prokaryotic DNA can be found in a coiled loop floating in the cytoplasm in a region called the nucleoid (meaning nucleus-like). In other words, the nucleoid is the area in a prokaryotic cell where DNA is located.

Explanation:

The DNA in prokaryotes is found in the nucleoid region, which is the central part of the cell where their single, circular chromosome is located along with concentrated DNA-associated proteins and plasmids. So the correct option is B.

The DNA in a prokaryote is located in a central part of the cell known as the nucleoid region. Prokaryotes, which include Bacteria and Archaea, have a single, circular chromosome that is not bound by a complex nuclear membrane. This chromosome is found within the nucleoid region, and this area does not readily stain, making it appear lighter in color when viewed with a transmission electron microscope. Additionally, the prokaryotic DNA and DNA-associated proteins are concentrated within this region. Prokaryotes often possess plasmids as well, which are shorter, circular DNA molecules that can carry traits such as antibiotic resistance and can be transferred independently during cell division.

Final answer:

When water boils, the water’s internal kinetic energy increases, and upon reaching the boiling point, the energy input turns into potential energy to convert water to steam. Air bubbles seen are not from the atmosphere but from dissolved gases, and the water's temperature does not increase beyond the boiling point.

Explanation:

When water is boiling in a pot, several physical changes occur. The water’s internal kinetic energy is increasing due to the heat supplied, which causes the water molecules to move faster. As the temperature of the water reaches the boiling point, the added energy goes into breaking the intermolecular forces, converting liquid water into water vapor, which is observed as boiling. This process is known as the phase transition from liquid to gas.

Air bubbles from the atmosphere are not being absorbed; instead, existing dissolved gases in the water can form bubbles. The water's temperature does not continue to increase once it reaches the boiling point, which for pure water at sea level is 100°C. At this point, any extra energy supplied by the stove is used to turn the water into steam, which is a process that involves gaining internal potential energy, rather than increasing temperature. Lastly, individual water molecules are indeed escaping from the pot, forming steam as they enter the gas phase.

Iron and aluminum are examples of elements, which are pure substances that cannot be broken down into simpler substances by chemical changes. Both are naturally occurring and widely used in various applications.

Iron and aluminum are examples of elements. Elements are pure substances that cannot be broken down into simpler substances by chemical changes. Iron and aluminum both occur naturally on earth and are widely used in various applications. For example, iron is a key component in steel making and is also an important element in hemoglobin in the blood, while aluminum is a good reducing agent and is used in a multitude of products such as foil and cookware. Other examples of elements include silver, gold, sulfur, oxygen, and copper.

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Answer:

athlete’s foot and ringworm- third choice

The two common fungal skin infections that humans can contract are athlete's foot and ringworm. They are both caused by fungi called dermatophytes, treated with antifungal creams and powders, and more persistent cases may require prescription medication.

The two common fungal skin infections that humans can contract are athlete's foot and ringworm.

Athlete's foot, medically known as tinea pedis, is a contagious infection that affects the skin on the feet and can spread to the toenails and sometimes the hands.

It is characterized by a scaly rash that usually causes itching, stinging, and burning.

Ringworm, or tinea corporis, is not caused by a worm but by a fungus, and it presents as a red, circular rash on the skin.

Both of these infections are caused by dermatophytes, which are fungi that feed on keratin, a protein found in skin, hair, and nails.

These infections are typically treated with over-the-counter antifungal creams and powders, although more persistent cases might require prescription medication.

Answer:

D. Extra-strong

Explanation:

a p e x

Answer:

either 58.1 or 1075

Explanation:

250 / 4.3 = 58.1

250 * 4.3

Answer:

Polar Covalent

Explanation:

Chlorine and Fluorine are both halogens. They are in group VII.

The Pauling's electronegativity value of these elements are:

F = 4.0

Cl = 3.0

Electronegativity of an element is a property that combines the ability of its atom to lose and gain electrons. It can be used to predict bond type.

For heteronuclear molecules where the electronegativity difference is between 0.5 and 1.7 there will not be an equal sharing of the electron pair between the atoms involved.

The bond that results is a Polar Covalent bond.

When the electronegativity difference is zero or less than 0.5, a non-polar covalent bond forms. There would be an equal sharing of the electron pair donated.

Answer:

Q1: 1.67 L.

Q2: Saturated solution.

Explanation:

Q1:

(MV) before dilution = (MV) after dilution

M before dilution = 10.0 M, V before dilution = 0.5 L.

M after dilution = 3.0 M, V after dilution = ??? L.

∴ V after dilution = (MV) before dilution / M after dilution = (10.0 M)(0.5 L) / (3.0 M) = 1.67 L.

Q2:

From the given curve, it is clear that the solubility of sodium nitrate at 35.0°C is 100 g per 100 g of water.

So, the mentioned solution is a saturated solution at this T.

A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent.

Earth's atmosphere is unique due to the presence of life that has influenced its composition, unlike the atmospheres of Venus and Mars, which do not support life and have atmospheres dominated by carbon dioxide and lacking in water vapor.So,option B is correct.

The composition of Earth's atmosphere is different from the atmospheres of Venus and Mars primarily because Earth has life, and Venus and Mars do not. This is option B. All three planets started with similar chemicals, but their evolutionary paths diverged because of factors such as their distance from the sun and geological activities. Earth's atmosphere, rich in oxygen and water vapor, not only supports life but has been shaped by it through processes like photosynthesis. In contrast, Venus has a thick atmosphere dominated by carbon dioxide with extreme surface pressure and temperature, making it hot and dry. Mars has a thin atmosphere, also mostly carbon dioxide, and is cold and dry, but it has signs that it once had conditions suitable for life.

The presence or absence of life significantly influences the atmospheric composition. Life on Earth has contributed to the oxygen levels and the presence of water vapor. The lack of life on Venus and Mars means that these planets have been unable to develop the same balance of gases that supports life here on Earth. Consequently, each planet's atmosphere is a result of its unique environmental conditions and history.

Answer:

The chemical name ends with “hydroxide.”

Explanation:

1- we write the name of the metal first and after that write the nonmetal:

Ex : NaOH ( sodium hydroxide)

2- any compound contains OH group is an ionic base and this group called hydroxide group

3- "Ous" ending is given in the ions with the lower oxidation.

4- " ic" ending is given in the ions with the higher oxidation.

So, the correct answer is: The chemical name ends with “hydroxide.”.

Answer:

The chemical name ends with “hydroxide

Explanation:

got right on edge 2020

Bromine --> Br: Period 4, Group 17 [Halogen]

C, because specific heat is measured in Joules/grams°C

Answer: B) 1 Calorie

Explanation: The heat required to raise the temperature of 1 gram of a substance by 1 degree C is known as its specific heat capacity.

Specific heat capacity of water is [tex]\frac{4.184Joule}{g*0_C}[/tex] and we know that, 4.184 Joule = 1 Calorie

So, specific heat capacity of water is [tex]\frac{1Calorie}{g*0_C}[/tex] and hence the correct choice is B.

Answer:

Ag(s) or Solid Silver. Silver in a solid phase has a face centered cubic crystal structure. Among your choices, silver is the only example of particles that are arranged in their crystal structure while the other choices are gases and liquid. Liquid and gases have loose atoms that do not form crystal structures.

Explanation:

Answer:

A) Homogeneous

Explanation:

Hope this helped :)

Answer:

9.32 g.

Explanation:

M = (no. of moles of NH₄Cl)/(Volume of the solution (L))

M = 0.875 M.

no. of moles of NH₄Cl = ??? mol,

Volume of the solution = 300 mL = 0.3 L.

∴ (0.875 M) = (no. of moles of NH₄Cl)/(0.3 L)

∴ (no. of moles of NH₄Cl) = (0.875 M)*(0.3 L) = 0.2625 mol.

no. of moles of NH₄Cl = mass/molar mass

∴ mass of NH₄Cl = (no. of moles of NH₄Cl)*(molar mass) = (0.2625 mol)*(53.491 g/mol) = 9.316 g ≅ 9.32 g.

The mass of ammonium chloride dissolved in 300 mL of a 0.875M solution is 14.90 g.

To find the mass of ammonium chloride dissolved in 300 mL of a 0.875M solution, we need to use the formula:

Mass = Volume x Concentration x Molar mass

The molar mass of ammonium chloride is 53.49 g/mol. Substituting the given values, we get:

Mass = 0.300 L x 0.875 mol/L x 53.49 g/mol = 14.90 g

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Answer:

Explanation:

A hydrated compound is one that contains water molecules chemically bonded. So,  the correct question is how many waters are bonded to sodium suilfate?

The latin prefix deca means ten (10), and the word hydrate means that contains water; then, decahydrate is used in chemistry to designate a compound that is bonded to 10 parts (molecules) of water.

Hence, sodium sulfate decahydrate means that each molecule of the compound is bonded to 10 molecules of water.

In the chemical formula, the water molecules of a hydrated compound are shown after the chemical formula of the compound using a period and a coefficient (the number of water molecules bonded) before the water molecules.

Then, given that the chemical formula for sodium sulfate is Na₂SO₄, the chemical formula for sodium sulfate decahydrate is Na₂SO₄·10H₂O.

Answer:

The limiting reactant is AlCl₃ and the excess reactant is NaOH.

Explanation:

3NaOH(aq) + AlCl₃(aq) → 3NaCl(aq) + Al(OH)₃(s)↓,

It is clear that 3.0 moles of NaOH(aq) react with 1.0 mole of AlCl₃(aq) to produce 3.0 moles of NaCl(aq) and 1.0 mole of Al(OH)₃(s).

no. of moles of NaOH = mass/molar mass = (8.0 g)/(40.0 g/mol) = 0.2 mol.

no. of moles of AlCl₃ = mass/molar mass = (4.0 g)/(133.34 g/mol) = 0.03 mol.

∴ 0.09 mol of NaOH (the remaining 1.1 mol is in excess) reacts completely with 0.03 mol of AlCl₃.

the limiting reactant is AlCl₃ and the excess reactant is NaOH.

Answer:

The molarity of the solution remains unchanged.

Explanation:

Consider the formula for the molarity [tex]M[/tex] of a solution:

[tex]\displaystyle M = \frac{n}{V}[/tex],

where

For this salt solution,

Initial molarity:

[tex]\displaystyle M_{0} = \frac{n_{0}}{V_{0}}[/tex].

Final molarity:

[tex]\displaystyle M_{1} = \frac{n_{1}}{V_{1}} = \frac{3\;n_{0}}{3\;V_{0}} = \frac{n_{0}}{V_{0}} = M_{0}[/tex].

In other words, the molarity of the solution remains unchanged.

Answer:

The molarity of the solution remains unchanged

Explanation:

Answer: The answer would be A;They measure the amount of greenhouse gases in the atmosphere, and the temperature over many years.

Explanation: If scientists only went off of clouds, they'd only be able to tell if it is about to rain. If they only observed the oceans, they'd only be able to tell when a tornado or tsunami was about to occur.

Answer: The answer is A. Thay measure the amount of greenhous gases in the atmosphere and the temperature over many years

Explanation:

Answer:

Explanation:

For work to be done, force must be applied to move an object in the direction of the applied force.

Work is the product of force and distance. Workdone describes a change of energy between places.

If we apply force to a body without moving it through a distance, no work is done.

Work is only done when force is applied to move or displace a body.

If we only apply force and no movement occurs, no work is done..

The unit of force is Joules.

In physics, work is done when a force is applied to an object and the object is displaced in the direction of the force. The work done is the product of the force's component in the direction of displacement and the distance the object moves. No displacement in the direction of the force means no work is done, even if effort is exerted.

In physics, for work to be done, two primary conditions must be fulfilled. First, a force must be applied to an object. Second, the object must experience a displacement in the direction of the force. If either of these conditions is not met, work is considered not to have occurred, regardless of the effort put in. For example, pushing against a wall with great effort does not constitute work unless the wall moves. If the wall does move, the energy used to cause this movement is the work done.

The work done is mathematically defined by the dot product of the force and displacement vectors, signifying that the direction of the force relative to the displacement is crucial in calculating the work performed. Therefore, when an external force causes an object to move, and this movement is in the same direction as the force, the product of the force's component along the direction of displacement and the distance moved is the work done. This could mean overcoming resisting forces like friction and moving a mass along a surface, or it could imply the conversion of one type of energy into another.

Answer:

a.) 86.01 g.

b.) 3.36 g.

c.) 0.394 m ≅ 0.40 m.

d.) 4.77%.

e.) 3.9%.

Explanation:

a.) mass of the solution:

The density of the solution is the mass per unit volume.

∵ Density of solution = (mass of solution)/(volume of the solution).

∴ Mass of the solution = (density of solution)*(volume of the solution) = (1.22 g/mL)*(70.5 mL) = 86.01 g.

b.) grams of sodium bromide  :

∵ M = (no. of moles of NaBr)/(Volume of the solution (L))

∴ no. of moles of NaBr = M*(Volume of the solution (L)) = (0.463 M )*(0.0705 L) = 0.0326 mol.

∵ no. of moles of NaBr = (mass of NaBr)/(molar mass of NaBr)

∴ mass of NaBr = (no. of moles of NaBr)*(molar mass of NaBr) = (0.0326 mol)*(102.894 g/mol) = 3.36 g.

c.) molality of the solution:

∵ m = (no. of moles of NaBr)/(mass of the soluvent (kg))

no. of moles of NaBr = 0.0326 mol,

mass of solvent = mass of the solution - mass of NaBr = 86.01 g - 3.36 g = 82.65 g = 0.08265 kg.

∴ m = (no. of moles of NaBr)/(mass of the soluvent (kg)) = (0.0326 mol)/(0.08265 kg) = 0.394 m ≅ 0.40 m.

d.) % (m/v) of the solution:

∵ (m/v)% = [(mass of solute) /(volume of the solution)]* 100

∴ (m/v)% = [(3.36 g)/(70.5 mL)]* 100 = 4.77%.

e.) % (m/m) of the solution:

∵ (m/m)% = [(mass of solute) /(mass of the solution)]* 100

∴ (m/m)% = [(3.36 g)/(86.01 g)] * 100 = 3.9 %.

Answer:

16.27 g.

Explanation:

Using cross multiplication:

1.0 mol of N₂ gas contains → 6.022 x 10²³ molecules.

??? mol of N₂ gas contains → 3.50 x 10²³ molecules.

∴ The no. of moles of N₂ gas = (1.0 mol)(3.50 x 10²³ molecules)/(6.022 x 10²³ molecules) = 0.5812 mol.

∴ The mass of 3.50 x 10²³ molecules of N₂ gas = (no. of moles)*(molar mass) = (0.5812 mol)(28.0 g/mol) = 16.27 g.

Final answer:

To calculate the mass of 3.50x10²³ molecules of nitrogen gas, we apply the concept of molar mass (28.01 g/mol) and Avogadro's number, resulting in a mass of approximately 16.3 grams.

Explanation:

To find the mass of 3.50x10²³ molecules of nitrogen gas (N₂), we must first understand the concept of molar mass and Avogadro's number (6.02x10²³ mol⁻¹). The molar mass of N₂ is 28.01 g/mol, which means one mole (6.02×10²³ molecules) of nitrogen gas has a mass of 28.01 grams.

To calculate the mass of 3.50×10²³ molecules, we use the proportion method:

1 mole (6.02×10²³ molecules) : 28.01 g = 3.50×10²³ molecules : X g

Solving for X gives us the mass of the nitrogen gas:

X = (3.50×10²³ / 6.02×10²³) × 28.01 g

Therefore, X = 16.3 grams (approximately).

This calculation illustrates how we can determine the mass of a specific number of gas molecules using the principles of molar mass and Avogadro's number.

The acid dissociation constant (Ka) for acetic acid, given the initial concentration of 0.200 M and the equilibrium concentration of H3O+ is 0.0019 M, is 1.82 × 10⁻µ.

To calculate the acid dissociation constant (Ka) for acetic acid, we can use the information provided that the initial concentration of acetic acid is 0.200 M and the equilibrium concentration of H3O+ is 0.0019 M. Using the chemical equation for the dissociation of acetic acid (CH3COOH):

CH3COOH(aq) ⇌ CH3COO−(aq) + H3O+(aq),

we know that at equilibrium, the concentration of H3O+ ions will be the same as the concentration of CH3COO− ions. Therefore, [CH3COO−] = [H3O+] = 0.0019 M.

Because acetic acid is a weak acid, we can assume that the change in concentration of acetic acid is roughly equal to the concentration of H3O+ ions produced. Thus, the equilibrium concentration of CH3COOH will be 0.200 M - 0.0019 M = 0.1981 M. The formula for Ka is:

Ka = [CH3COO−][H3O+] / [CH3COOH]

Substituting the equilibrium concentrations into this formula gives:

Ka = (0.0019 M)(0.0019 M) / (0.1981 M) = 1.82 × 10⁻µ,

which is the Ka for acetic acid.

Answer:

28.28 L.

Explanation:

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

P₁V₁ = P₂V₂

P₁ = 700.0 mm Hg, V₁ = 4.0 L.

at burst: P₂ = 99.0 mm Hg, V₂ = ??? L.

∴ V₂ = P₁V₁/P₂ = (700.0 mm Hg)(4.0 L)/(99.0 mm Hg) = 28.28 L.

Final answer:

The use of aerosol sprays and coolants that release chlorine and bromine gases contributes to ozone layer destruction, leading to increased UV radiation and environmental harm. The Montreal Protocol helped reduce emissions of ozone-depleting substances, slowing the rate of depletion.

Explanation:

The human activity that most likely contributes to ozone layer destruction is the release of chlorine and bromine gases through the use of products like aerosol sprays and coolants. These substances are known as ozone-depleting substances (ODS), and include chemicals such as chlorofluorocarbons (CFCs).

When these substances reach the stratosphere, they release halogen radicals that catalytically destroy ozone molecules, leading to ozone depletion. This has severe environmental and health impacts, such as increased UV radiation leading to higher rates of skin cancers and disrupted ecosystems. The Montreal Protocol was a successful international effort to phase out the production and use of ODS, which has led to a decrease in the rate of ozone depletion, but vigilance and continued reduction of emissions are essential to protect the ozone layer.

Answer:

impossible

Explanation:

Answer:

Kinetic energy

Potential energy

Motion energy

Answer:

Organic chemistry is a subdiscipline of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding. Study of structure determines their chemical composition and formula.

Answer:

3.125 grams.

Explanation:

∵ Thulium-167 has a half life of 9.0 days.

∴ The time is needed to calculate the grams are left after (36.0 days) represents (36.0 days / 9.0 days) = 4.0 half-lives.

50.0 grams → (first half life) 25.0 grams → (second half life) 12.5 grams → (third half life) 6.25 grams → (fourth half life) 3.125 grams.

So, the grams are left after 36.0 days = 3.125 grams.

Answer:

C: It is conserved

Explanation:

The reaction neither lost (exothermic) or gained (endothermic) energy, therefore the total energy remained the same and was conserved.

Answer:

D: It is converted

Explanation:

according to the law of conservation of energy:

In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time.

Meaning that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another without any loss of energy