Which of the following statements is true? Temperature is the same as heat. Heat can travel through a vacuum. Heat has shorter wavelengths than visible light. All of the above.

Answer: N2o4 - N2 + 202

Explanation:

[tex]\boxed{{\text{22}}{\text{.69 g}}}[/tex] of methanol must be burned to produce 541 kJ of heat.

Further explanation:

Combustion reaction:

It is the reaction in which the reactant reacts with molecular oxygen to form carbon dioxide and a water molecule. Molecular oxygen acts as the oxidizing agent in these reactions. A large amount of heat is released and therefore combustion reactions are exothermic in nature.

The change in enthalpy that occurs due to the formation of one mole of the compound from its constituent elements is called the standard enthalpy of formation. It is represented by [tex]\Delta {H_{{\text{rxn}}}}[/tex] and its units are kJ/mol.

The combustion of methanol occurs as follows:

[tex]{\text{C}}{{\text{H}}_3}{\text{OH}}+\frac{3}{2}{{\text{O}}_2}\to{\text{C}}{{\text{O}}_2}+2{{\text{H}}_{\text{2}}}{\text{O}}[/tex]

The value of [tex]\Delta {{\text{H}}_{{\text{reaction}}}}[/tex] is -764 kJ/mol. This indicates the heat produced when one mole of methanol is combusted. The negative sign means the heat is released during the process.

The number of moles of methanol [tex]\left( {{\text{C}}{{\text{H}}_3}{\text{OH}}} \right)[/tex] required in the given reaction is calculated as follows:

[tex]\begin{aligned}{\text{Moles of C}}{{\text{H}}_3}{\text{OH}}&=\left({541{\text{ kJ}}} \right)\left( {\frac{{{\text{1 mol}}}}{{764{\text{ kJ}}}}}\right)\\&=0.708{\text{ mol}}\\\end{aligned}[/tex]

The formula to calculate the mass of methanol [tex]\left( {{\text{C}}{{\text{H}}_3}{\text{OH}}} \right)[/tex] is as follows:

[tex]{\text{Mass of C}}{{\text{H}}_3}{\text{OH}}=\left({{\text{Moles of C}}{{\text{H}}_3}{\text{OH}}}\right)\left({{\text{Molar mass of C}}{{\text{H}}_3}{\text{OH}}}\right)[/tex]          ...... (1)

The number of moles of [tex]{\text{ C}}{{\text{H}}_3}{\text{OH}}[/tex] is 0.708 mol.

The molar mass of [tex]{\text{ C}}{{\text{H}}_3}{\text{OH}}[/tex] is 32.04 g/mol.

Substitute these values in equation (1).

[tex]\begin{aligned}{\text{Mass of  C}}{{\text{H}}_3}{\text{OH}}&=\left({{\text{0}}{\text{.708 mol}}} \right)\left({\frac{{{\text{32}}{\text{.04 g}}}}{{{\text{1 mol}}}}}\right)\\&=22.688{\text{ g}}\\&\approx {\text{22}}{\text{.69 g}}\\\end{aligned}[/tex]

Therefore the mass of methanol burned is 22.69 g.

Learn more:

1. Calculate [tex]\Delta {\text{H}}[/tex] for the reaction using Hess law: https://brainly.com/question/11293201

2. Calculate the hydroxide ion concentration: https://brainly.com/question/11293214

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Thermodynamics

Keywords: methanol, CH3OH, combustion, 746 kJ, 541 kJ, mass of CH3OH, molar mass of CH3OH, 22.69 g, moles of CH3OH.

To determine the limiting reactant between sulfuric acid and aluminum hydroxide, calculate the moles of each reactant using their molar masses. Comparisons based on the stoichiometric ratios from the balanced chemical equation reveal that sulfuric acid is the limiting reactant.

To identify the limiting reactant when 34 g of sulfuric acid reacts with 33 g of aluminum hydroxide, we need to calculate the moles of each reactant based on their molar masses. The balanced chemical equation for the reaction between sulfuric acid (H₂SO₄) and aluminum hydroxide (Al(OH)₃) is:

3 H₂SO₄(aq) + 2 Al(OH)₃(s) → Al₂(SO₄)₃(aq) + 6 H₂O(l)

First, determine the molar mass of H₂SO₄, which is approximately 98 g/mol, and Al(OH)₃, which is approximately 78 g/mol. Then, calculate the moles of each reactant:

The balanced equation shows that 3 moles of H₂SO₄ react with 2 moles of Al(OH)₃. We then set up ratios to see which reactant is limiting:

Since we only have 0.347 moles of H₂SO₄ but require 0.635 moles to react with all the available Al(OH)₃, sulfuric acid is the limiting reactant.

To find the mass of 0.560 moles of chromium, multiply the number of moles by the molar mass of chromium (51.996 g/mol), resulting in 29.11816 grams.

Explanation:

To calculate the mass of chromium found in a 2.50 g sample of stainless steel, we need to know the percentage composition of chromium in the alloy. However, the question provides data for 0.560 moles of chromium and not the composition of the stainless steel sample. To find the mass of 0.560 moles of chromium, we use the molar mass of chromium.

Steps to Calculate Mass of Chromium

Performing this calculation: 0.560 moles × 51.996 g/mol = 29.11816 grams of chromium.

Answer:

_+_

Explanation:

Answer: C) 154 g

I did the assignment already, it's correct.

The number of atoms of any element in the given chemical formula is the number that is written on the food of the symbol of that element. The total number of atoms of oxygen in given molecule is 9.033  ×10²³.

Atom is the smallest particle of any matter. Atom combines to form element and element combine to form molecule or compound. Atom can be further divided into electron, protons and neutrons.

1 molecule of given molecule contain 5 atoms of oxygen

Molar mass of N₂O₅= 108.01 g/mol

given mass of  N₂O₅=32.4 g

Number of moles of N₂O₅= given mass÷molar mass =0.3mol

Number of atoms= 0.3 ×6.022×10²³

Number of atoms=1.8066 ×10²³

total number of atoms=5×1.8066 ×10²³

                                    =9.033  ×10²³atoms of oxygen

Thus the total number of atoms of oxygen in given molecule is 9.033  ×10²³.

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Final answer:

approximately 9.033 x 10^23 oxygen atoms.

Explanation:

Calculating the Number of Oxygen Atoms in 32.4 g of N2O5

To determine the number of oxygen atoms in 32.4 g of N2O5, we first need to understand the concept of moles and how it relates to the mass of a substance. N2O5 has a molecular mass of 108.02 amu. This means one mole of N2O5 weighs 108.02 grams and contains Avogadro's number of molecules. Using the equation for calculating moles, where n is the number of moles, m is the mass of the substance in grams, and M is the molar mass of the substance in g/mol, the formula is:

n = m / M

Substituting the given values:

n = 32.4 g / 108.02 g/mol ≈ 0.3 moles of N2O5

Since each molecule of N2O5 contains 5 oxygen atoms, we multiply the number of moles of N2O5 by 5 and then by Avogadro's number (6.022 x 1023) to get the total number of oxygen atoms:

Total oxygen atoms = 0.3 moles x 5 x 6.022 x 1023 ≈ 9.033 x 1023 oxygen atoms

The radon is the decay byproduct of radium which emits alpha rays to convert into the lead or polonium. The alpha particles have less penetration inside the cell than the beta particle or gamma rays and have the more dangerous effect than these other days. In the environment, the high presence of radon enters into the lungs through breathing and start to decay. In their decay, it emits alpha rays, which acts as the carcinogenic agent in the body.

Answer: Potential energy of products is less than the potential energy of the reactants.

Explanation:

Exothermic reactions are defined as the reactions which releases heat. The release in heat is due to the difference in the potential energy of the reactants and the products.

For these reactions, the potential energy of the products is less than the potential energy of the reactants. Total enthalpy change of the reaction is given by the equation:

[tex]\Delta H_{rxn}=\sum H_{products}-\sum H_{reactants}[/tex]

For exothermic reaction, [tex]\Delta H_{rxn}[/tex] is negative.

For the reaction of baking soda and vinegar, the equation follows:

[tex]NaHCO_3+CH_3COOH\rightarrow CH_3COONa+CO_2+H_2O+\text{ energy}[/tex]

As, the energy is written at the product side, this means that the reaction between baking soda an=d vinegar is an exothermic reaction.

The right answer is the salts precipate out of solution.

There are two types of current evaporites:

* the evaporites of free water, coming from the evaporation of a body of water;

* capillary evaporites resulting from the precipitation of the salts of an intertitle brine in the pores of a sediment.

The formation of evaporites is favored by the arid climate and the confinement of the environment. Nevertheless temperate but very windy coastal areas are also the seat of a strong evaporation.

In the current salt marshes, the confinement of the body of water is accompanied by an intense biological activity: insect larvae, algae, bacteria.

To calculate the number of moles of H2O formed, determine the moles of CH3OH involved in the reaction, convert the volume of CH3OH to mass using its density, convert the mass of CH3OH to moles using its molar mass, and use the balanced chemical equation to determine the stoichiometry between CH3OH and H2O.

To calculate the number of moles of H2O formed, we first need to determine the number of moles of CH3OH and O2 involved in the reaction.

1. Convert the volume of CH3OH to mass using its density:

Mass of CH3OH = Volume of CH3OH x Density = 50.0 mL x 0.850 g/mL = 42.5 g

2. Convert the mass of CH3OH to moles using its molar mass:

Moles of CH3OH = Mass of CH3OH / Molar mass of CH3OH = 42.5 g / 32.04 g/mol = 1.327 mol

3. Use the balanced chemical equation to determine the stoichiometry between CH3OH and H2O:

1 mol of CH3OH produces 2 mol of H2O

Therefore, 1.327 mol of CH3OH will produce 2 x 1.327 = 2.654 mol of H2O

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Answer:

Metals are malleable due to the layers of atoms which can move over each other. Ionic crystals are made of rigid lattice structures

Explanation:

The molecular structure of metals consists of metallic ions in a sea of de-localized electrons. The ions are closely packed in a regular arrangement. The layers of ions are held together due to the electrostatic forces between the ions and electrons. The layers of ions are not bonded to each other directly, which allows them to move when force is applied. This is why metals are malleable

Ionic crystals are strongly bonded lattice structures with oppositely charged ions strongly attracted to each other. As the ions are bonded directly to each other, the application of a force has the potential to break existing bonds, making the structure brittle.

Explanation:

Number of Ca atom = 1

Number of S atom = 1

Number of O atom = 6

Number of H atom = 2

Number of Ca atom = 2 × 6 = 12

Number of H atom = 2 × 10 = 20

Number of O atom = 2 × 5 = 10

Number of Al atom = 2

Number of Cl atom = 1

Number of O atom = 5

Number of H atom = 5

Final answer:

The predominant intermolecular force in (CH3)2NH is hydrogen bonding, a strong type of dipole-dipole interaction that occurs due to the presence of highly electronegative nitrogen atoms.

Explanation:

The predominant intermolecular force in (CH3)2NH is hydrogen bonding. This is a special type of dipole-dipole interaction that occurs when hydrogen is bonded to a highly electronegative atom such as nitrogen (N). In (CH3)2NH, the hydrogen atoms attached to the nitrogen can form hydrogen bonds with the nitrogen atoms of adjacent molecules because nitrogen is one of the three most electronegative elements capable of forming hydrogen bonds, along with oxygen (O) and fluorine (F). While London dispersion forces are also present, they are generally weaker than hydrogen bonds and are not the predominant force in this compound.

The solution follows as;

Given:

CuSO4 – 9.70 (weight)

Water / H2O – 12.98 – 9.70 = 3.28 (weight)

Molecular weight of CuSO4 – 160

Molecular weight of H2O – 18

To solve;

= weight of CuSO4 x MW of CuSO4

= 970 / 160

= 328/x*18

= 6x = 18

= x – 3

= CuSO4*3H2O

Answer:

3.00 * 293 / 4.00

Explanation:

Using Charles's law, which states the direct proportionality between volume and temperature of a gas at constant pressure, the final temperature needed for the gas to reach a volume of 3.00 liters is approximately 219.75 K.

The question is asking about the relationship between the volume and temperature of a gas at constant pressure. This relationship is described by Charles's law, which states that the volume of a gas is directly proportional to its temperature when pressure is held constant. In mathematical terms, V1/T1 = V2/T2, where V1 and T1 are the initial volume and temperature, and V2 and T2 are the final volume and temperature.

Given the initial volume of 4.00 liters and temperature of 293 K, if the volume decreases to 3.00 liters, we can solve for the new temperature using Charles's law:

(4.00 L / 293 K) = (3.00 L / T2)

By cross-multiplying and solving for T2, we get:

T2 = (3.00 L * 293 K) / 4.00 L = 219.75 K

So, for the volume of the gas to become 3.00 liters at constant pressure, the kelvin temperature must be approximately 219.75 K.

Answer:

Na+

Explanation:

Atoms may loose or gain electrons in order to attain octate.

Chemical species obtained after loosing or gaining electrons are called ions.

When an element losses electrons, positively charged ion is formed.

When an element gains electrons, negatively charged ion is formed.

Among the given, only Na+ carry a positive charge, rest are neutral.

Therefore, Na+ is an ion.

Answer:

The correct answer is A. Double-Displacement

Explanation:

A double displacement reaction is that two elements found in different compounds exchange positions, forming two new compounds. These chemical reactions do not present changes in the number of oxidation or relative load of the element. Generally the exchange occurs between reagents that are ionic compounds in solution, where the anions and cations of the compounds are exchanged.

Double displacement reactions follow the following general chemical equation:

AB + CD --- AD + CB

The initial compounds AB and CD react by exchanging "their partners" and thus form two new compounds: AD and CB. This reaction takes place if and only if A and D are more similar than A and C, or if CB links are more stable than those of CD. Since the reaction is a simple ion exchange, none of these gain or lose electrons, as mentioned above. Thus, if A is a +1 charge cation in compound AB, it will have the same +1 charge in compound AD.

The solvent of the double displacement reactions is almost always water and the reagents and products are usually ionic compounds, although they can also be acids or bases.

On the other hand, a precipitation reaction occurs when two aqueous ionic compounds form a new ionic compound that is not soluble in water. It is an example of double displacement reactions. In most precipitation reactions, one salt is soluble and the other precipitates. The insoluble compound that results is called precipitate. The solvent and soluble reaction compounds are called the supernatant. This is the type of reaction that happens in this case. In this case the insoluble compound is cadmium sulfide CdS.

Answer:C

Explanation:

To calculate the initial velocity of a rock thrown 1.8 meters in the air, we use the vertical motion equation, resulting in an initial velocity of approximately 5.94 m/s.

To find out how fast a rock was thrown 1.8 meters in the air, we can use the physics of projectile motion and the equations of motion under the influence of gravity. Given that the height reached by the rock is 1.8 meters, we can use the equation for vertical motion:

h = vi2 / (2g),

where h is the maximum height (1.8 meters), vi is the initial velocity we want to calculate, and g is the acceleration due to gravity (9.8 m/s2). Rearranging the formula to solve for the initial velocity gives us:

vi = sqrt(2gh).

Plugging in the values, we get:

vi = sqrt(2 * 9.8 m/s2 * 1.8 m) = sqrt(35.28) ≈ 5.94 m/s.

Thus, the rock was thrown upwards with an initial velocity of approximately 5.94 m/s.

Using the kinematic equation v^2 = u^2 + 2as, the initial velocity (u) at which the rock was thrown into the air is found to be approximately 5.94 m/s.

To calculate the initial velocity at which a rock is thrown into the air, we can use the kinematic equations for projectile motion. Since air resistance is negligible, we'll apply the equation for an object under uniform acceleration due to gravity.

The equation we use is v^2 = u^2 + 2as, where:

Rearranging the equation to solve for the initial velocity (u), we get:

u = √(v^2 - 2as)

Plugging in the known values:

u = √(0^2 - 2*(-9.8 m/s^2)*(1.8 m))

u = √(0 + 35.28)

u = √35.28

u = 5.94 m/s

The rock was thrown with an initial velocity of approximately 5.94 m/s.

Final answer:

The net ionic equation for the reaction between solid chromium(III) hydroxide and nitrous acid is Cr(OH)3(s) + 3 H+(aq) → Cr3+(aq) + 3 H2O(l), after removing the spectator nitrate ions.

Explanation:

The question involves writing a net ionic equation for the reaction between solid chromium(III) hydroxide and nitrous acid. To start, write down the full balanced molecular equation:

Cr(OH)3(s) + 3 HNO2(aq) → Cr(NO3)3(aq) + 3 H2O(l)

Now write the full ionic equation:

Cr(OH)3(s) + 3 H+(aq) + 3 NO2⁻(aq) → Cr3+(aq) + 3 NO2⁻(aq) + 3 H2O(l)

Notice that the nitrate ions (NO2⁻) are present on both sides of the equation and thus are spectator ions. Removing the spectator ions gives us the net ionic equation:

Cr(OH)3(s) + 3 H+ (aq) → Cr3+ (aq) + 3 H2O(l)

It's important to verify that both sides of the equation are balanced with respect to both charge and mass. The equation above satisfies this requirement, with three positive charges on both sides and the same number of each type of atom on each side.

Final answer:

The net ionic equation for the reaction of solid chromium (iii) hydroxide with nitrous acid is Cr(OH)₃(s) + 3 HNO₂(aq) → Cr₃+(aq) + 3 NO₂−(aq) + 3 H₂O(l).

Explanation:

The net ionic equation for the reaction of solid chromium (iii) hydroxide with nitrous acid is:

Cr(OH)₃(s) + 3 HNO₂(aq) → Cr₃+(aq) + 3 NO₂−(aq) + 3 H₂O(l)

First, solid chromium (iii) hydroxide reacts with nitrous acid to form chromium ions, nitrite ions, and water.

In this reaction, the hydroxide ions combine with the hydrogen ions from the acid to produce water, and chromium (iii) hydroxide dissolves to leave behind chromium ions in solution.

Since chromium (iii) hydroxide is a weak base and does not dissociate into ions in its solid state, it is included as a whole compound in the net ionic equation. The nitrite ions and chromium ions remain in solution, indicating a chemical change has occurred.