A calorimeter contains 21.0 mL of water at 13.5 ∘C. When 1.70g of X (a substance with a molar mass of 77.0 g/mol) is added, it dissolves via the reaction X(s)+H2O(l)→X(aq) and the temperature of the solution increases to 25.0 ∘C.

Calculate the enthalpy change, ΔH , for this reaction per mole of X.

Assume that the specific heat of the resulting solution is equal to that of water [4.18 J/(g⋅∘C)], that density of water is 1.00 g/mL, and that no heat is lost to the calorimeter itself, nor to the surroundings.

Express the change in enthalpy in kilojoules per mole to three significant figures.

Answer:

i cannot see the picture

Explanation:

Answer:

many milliliters of 1.50 M HCl(aq) are required to react with 5.05 g Zn(s)?

volume: 16 mL

First, we need to calculate the number of moles of Zn:

m(Zn) = 5.05 g

M(Zn) = 65.38 g/mol (molar mass of Zn)

n(Zn) = m(Zn) / M(Zn) = 5.05 g / 65.38 g/mol = 0.0773 mol

According to the balanced chemical equation, 1 mole of Zn reacts with 2 moles of HCl. Therefore, the number of moles of HCl needed is:

n(HCl) = 2 × n(Zn) = 2 × 0.0773 mol = 0.1546 mol

Now we can use the molarity of the HCl solution to calculate the volume needed:

M(HCl) = 1.50 mol/L

n(HCl) = V(HCl) × M(HCl)

V(HCl) = n(HCl) / M(HCl) = 0.1546 mol / 1.50 mol/L = 0.103 L = 103 mL

Therefore, we need 103 mL of 1.50 M HCl(aq) to react with 5.05 g Zn(s).

Answer:

Acids are corrosive substances that can be dangerous if not handled properly. They have a pH level of less than 7, and can cause chemical burns, skin and eye irritation, respiratory problems, and other health hazards if they come into contact with human tissue. Here are some reasons why acids should be handled with great care:

Corrosive Properties: Acids have the ability to dissolve or corrode many materials, including metals, plastics, and organic compounds. This means that they can cause damage to equipment, clothing, and skin if not handled with care.

Toxicity: Some acids can be toxic if ingested or inhaled, and can cause severe health problems or even death. For example, hydrochloric acid, which is commonly used in industrial settings, can cause severe burns to the skin and respiratory system.

Reactivity: Acids can react with other chemicals to produce hazardous fumes or explosions. For example, when mixed with bleach, hydrochloric acid can produce chlorine gas, which can be deadly if inhaled.

Environmental Concerns: Acids can also have negative environmental impacts if not disposed of properly. They can contaminate waterways and harm aquatic life, and can contribute to air pollution if released into the atmosphere.

Therefore, it is important to handle acids with great care and to follow proper safety procedures when working with them to avoid any negative health, safety, or environmental consequences.

Erik should mix equal amounts of each soil type with an equal amount of water in separate jars and let them sit undisturbed for several hours to compare the amount of water absorbed by each soil.

To test clay, silt, and sandy soils for how well they hold water, Erik should conduct a simple investigation using the same amount of each soil type and equal amounts of water.

He can begin by taking three different jars and filling each one with the same amount of soil from each type. Then, he should add an equal amount of water to each jar and mix the contents thoroughly.

After mixing, he should allow the jars to sit undisturbed for several hours to allow the water to be absorbed by the soil. He can then measure the amount of water left in each jar and compare the results. This will help Erik determine which soil type holds water better than the others.

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B) Planck's constant (h)

Explanation:

The balanced chemical equation for the reaction between sulfuric acid and potassium hydroxide is:

H₂SO4(aq) + 2KOH(aq) → K₂SO4(aq) + 2H₂O(l)

From the equation, we can see that 1 mole of H₂SO4 reacts with 2 moles of KOH. We can use this information to determine the number of moles of H₂SO4 and KOH present in the mixture before neutralization:

moles of H₂SO4 = 0.850 L x 0.400 mol/L = 0.34 mol

moles of KOH = 0.800 L x 0.250 mol/L = 0.20 mol

Since KOH is the limiting reagent, it will be completely consumed in the reaction. The number of moles of H₂SO4 that reacts with the KOH is given by:

moles of H₂SO4 reacted = 2 x moles of KOH = 0.40 mol

The remaining moles of H₂SO4 after neutralization is:

moles of H₂SO4 remaining = moles of H₂SO4 - moles of H₂SO4 reacted

moles of H₂SO4 remaining = 0.34 mol - 0.40 mol

moles of H₂SO4 remaining = -0.06 mol

Since the moles of H₂SO4 remaining is negative, it means that all of the H₂SO4 has reacted with the KOH and there is an excess of KOH. Therefore, the concentration of sulfuric acid remaining after neutralization is 0 M.

Answer:

Explanation:

MTBE (C5H12O)

A. The hydronium ion concentration, [H₃O⁺] of the solution is 4.57×10⁻⁸ M

B. The hydroxide ion concentration, [OH⁻] of the solution is 1.28×10⁻⁶ M

C. The hydroxide ion concentration, [OH⁻] of the solution is 1.80×10⁻¹¹ M

We can determine the [H₃O⁺] of the solution as shown below:

[H₃O⁺] × [OH⁻] = 10¯¹⁴

[H₃O⁺] × 2.19×10⁻⁷ = 10¯¹⁴

Divide both side by 2.19×10⁻⁷

[H₃O⁺] = 10¯¹⁴ / 2.19×10⁻⁷

[H₃O⁺] = 4.57×10⁻⁸ M

We can determine the [OH⁻] of the solution as shown below:

[H₃O⁺] × [OH⁻] = 10¯¹⁴

7.81×10⁻⁹ × [OH⁻] = 10¯¹⁴

Divide both side by 7.81×10⁻⁹

[OH⁻] = 10¯¹⁴ / 7.81×10⁻⁹

[OH⁻] = 1.28×10⁻⁶ M

We can determine the [OH⁻] of the solution as shown below:

[H₃O⁺] × [OH⁻] = 10¯¹⁴

5.57×10⁻⁴ × [OH⁻] = 10¯¹⁴

Divide both side by 5.57×10⁻⁴

[OH⁻] = 10¯¹⁴ / 5.57×10⁻⁴

[OH⁻] = 1.80×10⁻¹¹ M

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An example of solar energy being used in the U.S is in the heating of swimming pools, and powering of cabins in off grid regions.

14. Using hydrogen as a fuel source involves using it as a primary energy carrier to power vehicles or generate electricity. It can be combined with oxygen to create water, producing energy in the process. The process of using hydrogen as a fuel source is known as hydrogen fuel cell technology, which involves the conversion of chemical energy into electrical energy.

15. Hydrogen is the most abundant element in the universe but is rarely found in its pure form on Earth. It is usually found in combination with other elements such as oxygen in water, carbon in hydrocarbons, and nitrogen in ammonia. Hydrogen can be extracted from water, natural gas, coal, and biomass through various methods such as steam-methane reforming, electrolysis, and biomass gasification.

16. Advantages of using hydrogen as a fuel source include:

Disadvantages of using hydrogen as a fuel source include:

17. A fuel cell is an electrochemical device that converts chemical energy into electrical energy through a chemical reaction between hydrogen and oxygen. It consists of an anode, a cathode, and an electrolyte, with the hydrogen fuel entering the anode and the oxygen entering the cathode. The hydrogen molecules are split into protons and electrons, with the protons passing through the electrolyte and the electrons flowing through an external circuit, generating electricity. The oxygen combines with the protons and electrons at the cathode, producing water as the only byproduct.

18. Solar energy is a form of renewable energy that is derived from the sun's radiation. It is harnessed through various technologies such as photovoltaics, solar thermal systems, and concentrated solar power to generate electricity, heat water, and power homes and businesses.

19. A solar cell is a semiconductor device that converts sunlight directly into electricity through the photovoltaic effect. It is made of a thin layer of a semiconductor material such as silicon that is treated with impurities to create a p-n junction. When sunlight strikes the cell, it creates an electric field that separates the positively charged holes and negatively charged electrons, generating an electric current.

20. Advantages of using solar energy include:

Disadvantages of using solar energy include:

21. An example of solar energy being used in the U.S is in the heating of swimming pools, and powering of cabins in off grid regions.

Answer:

3 moles H2 x (molecules / 1 mol H2)

Explanation:

3 moles H2 x (molecules / 1 mol H2)

The mass(in grams) of iron, Fe produced from the 92.5g of iron (ii) oxide, FeO is 71.9 grams

The mass of Fe produced from the 92.5g of iron (ii) oxide, FeO can be obtained as follow:

2FeO → 2Fe + O₂

From the balanced equation above,

143.7 g of FeO reacted to produce 111.7 g of Fe

Therefore,

92.5 g of Fe will react to produce = (92.5 × 111.7) / 143.7 = 71.9 g of Fe

Thus, the mass of Fe produced from the reaction is 71.9 grams

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Complete question:

How many grams of Fe are produced from 92.5 g of FeO given the following reaction 2FeO → 2Fe + O₂

4.5 billion years old

hope this helps

Answer:

Earth's water is 4.5 billion years old.

Explanation:

Water is a transparent, odorless, tasteless liquid, a compound of hydrogen and oxygen, H2O, freezing at 32°F or 0°C and boiling at 212°F or 100°C, that in a more or less impure constitutes rain, oceans, lakes, rivers, etc.: it contains 11.188 percent hydrogen and 88.812 percent oxygen, by weight.

Answer: The smallest whole-number ratio of the atoms in a compound represents the molar ratio of the elements in which they are combined. For example, Water is a compound. The chemical formula of water is H2O H 2 O . In water, H and O elements are combined in the molar ratio of 2:1.Explanation:

Answer:

[tex]emperical \: formula[/tex]

Answer:

Solubility.

Explanation:

Solubility is the maximum concentration of a solute that can dissolve in a solvent at a given temperature. At the maximum concentration of solute, the solution is said to be saturated. The units of solubility can be provided in mol/L or g/L.

Answer:

Explanation:

% comp is g element / g cpd x 100%  get the grams from the periodic table

1) 77.78%Fe & 22.22 % O

2) 40.68 % Mg & 59.32 % Cl

3) 75 % C & 25% H

4) 15.79% C & 84.21 % S

5) 30.43 % N & 69.57 % 0

6) 92.63%Hg & 7.37 % )

7) 18.98 % Sn &  81.02 %I

8) 88.89 % Cu & 11.11 % O

9) 82.35 & N & 17.65 % H

10) 40% C & 6.67% H & 53.33 % O

According to the kinetic molecular theory, gases are described by the following statement:

This statement highlights that gases are made up of particles that are in constant motion, moving in straight lines until they collide with another particle or the walls of the container.

The motion of gas particles is random, and their energy increases as the temperature of the gas increases. The kinetic molecular theory also suggests that the particles in a gas are far apart from each other and do not attract or repel each other, except during collisions.

Additionally, the kinetic molecular theory states that the pressure of a gas is caused by the collisions of gas particles with the walls of the container. The higher the concentration of gas particles or the faster they are moving, the greater the pressure of the gas.

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Answer:2.115 L

Explanation:

4.5 x .47 = 2.115 L

4.5 pints are approximately equal to 2.129292 liters. The answer closes to the result is 2.215 liters.

This question is concerned with conversion between pints and liters. 1 pint is equal to approximately 0.473176 liters. Therefore, to find out how many liters that 4.5 pints is equal to, we multiply 4.5 by 0.473176.

The calculation is as follows: 4.5 pints * 0.473176 liters/pint = 2.129292 liters

Considering the options that was given, the closest answer is 2.215 liters.

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Answer:

massR = massP

massA + massB = massAB

18g + 4g = 22g

Explanation:

Scientific notation is a method of expressing numbers that are too large or too tiny to be represented in decimal form because it would need an extremely long string of digits.

Numbers significantly larger or smaller than these are difficult to read and write because it is simple to count the zeros incorrectly. Using exponential notation is easier. Very large numbers can be expressed as an ordinary (fixed point) number, a letter E, and a whole number. The full number indicates how many places to the right the fixed point number's decimal point must be shifted to acquire the same value as an ordinary number.

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Answer:

D

Explanation:

because replusive force is much more

22. Wind energy comes from the movement of air caused by the uneven heating of the Earth's surface by the sun. As the sun heats up different parts of the Earth's surface, the air above them heats up and rises, creating a low-pressure area

23. Wind energy is converted into electrical energy using wind turbines.

Wind energy is renewable and does not produce greenhouse gas emissions or air pollutants, making it a clean source of energy.

Wind energy can be produced locally, reducing dependence on foreign oil and creating jobs in the local economy.

Wind turbines have a relatively small land footprint compared to other power sources.

Wind energy can be intermittent and variable, as wind speeds can vary depending on location and time of day.

Wind turbines can have negative impacts on wildlife, particularly birds and bats, and their habitats.

Wind turbines can have visual and noise impacts on nearby communities.

25. One example of wind energy being used to create electricity in the U.S. is the Alta Wind Energy Center in California.

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The total number of moles of reactants and products in the chemical reaction given is 9 moles

The total number of mole of reactants and products in the chemical reaction can be obtained as follow:

2H₂S + 3O₂ -> 2H₂O + 2SO₂

The following were obtained from the above equation:

Total number of mole = Mole of reactants + mole of products

Total number of mole = 5 mole + 4 moles

Total number of mole = 9 moles

Thus, we can say that the total number of mole is 9 moles

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To determine the number of HCl molecules in 4.91 L of HCl acid at 25°C, we can use the following steps:

[tex]\qquad\sf {Density = \dfrac{mass}{volume}}[/tex]

[tex]\qquad\sf{mass = density \times volume}[/tex]

[tex]\qquad\sf{mass = 1.096 \: g/mL \times 4.91\: L = 5.38\: kg}[/tex]

Convert the mass of HCl acid to the number of moles using its molar mass. The molar mass of HCl is 36.46 g/mol.

[tex]\sf{moles = \dfrac{mass}{ molar\: mass} = \dfrac{5.38\: kg}{36.46\: g/mol} = 147.6\: mol}[/tex]

Use Avogadro's number to convert the number of moles of HCl to the number of HCl molecules. Avogadro's number is [tex]6.02 \times 10^23[/tex] molecules/mol.

[tex]\sf number\: of\: HCl\: molecules = moles \times Avogadro's\: number[/tex]

[tex]\begin{aligned}\sf number\: of\: HCl\: molecules& =\sf 147.6 \: mol \times 6.02 \times 10^23\: molecules/mol \\& =\sf 8.88 \times 10^25\: molecules\end{aligned}[/tex]

Therefore, there are [tex]8.88 \times 10^25[/tex] HCl molecules in 4.91 L of HCl acid at 25°C, assuming the density of the acid is 1.096 g/mL.

[tex]\rule{200pt}{5pt}[/tex]

The most suitable separation technique for this mixture is a combination of magnetic separation and filtration.

First, a magnet can be used to separate the iron fillings from the sand and salt mixture. This is because iron is magnetic and will be attracted to the magnet, leaving the sand and salt behind.

Next, the sand and salt mixture can be dissolved in water. Since salt is soluble in water but sand is not, the salt will dissolve while the sand remains behind. The mixture can then be filtered to separate the sand from the saltwater solution.

Finally, the saltwater solution can be heated to evaporate the water and obtain the salt as a solid residue.

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Answer:

0.275M

Explanation:

First, we need to determine the number of moles of oxalic acid dihydrate used in the titration:

moles of H2C2O4 • 2H2O = (0.284 g) / (126.07 g/mol) = 0.00225 mol

Since oxalic acid dihydrate is diprotic, it can react with two moles of NaOH per mole of H2C2O4 • 2H2O. Therefore, to determine the molarity of the NaOH solution, we need to divide the number of moles of NaOH used in the titration by the volume of NaOH solution used:

moles of NaOH = (0.00225 mol H2C2O4 • 2H2O) x (2 mol NaOH / 1 mol H2C2O4 • 2H2O) = 0.0045 mol

molarity of NaOH = (0.0045 mol) / (0.01637 L) = 0.275 M

Therefore, the molarity of the NaOH solution is 0.275 M.

The chemical of hydrogen has 0.0426 moles per y.

A compound combines with an oxidising element, such as oxygen, in a complete combustion reaction, and the products are compounds of each element in the fuel and the oxidising element. This reaction is exothermic. For instance, Carbon dioxide(g) + 2water(g) + heat + light = Methane(g) + 2Oxygen(g).

Molar mass of water (Water) = 2(1.008 g/mol) + 1(15.999 g/mol) = 18.015 g/mol

moles of water = mass of water collected / molar mass of water

moles of water = 0.384 g / 18.015 g/mol

moles of water = 0.0213 mol

Therefore, 0.0213 mol of water were produced from the combustion of the compound.

To determine the moles of hydrogen in the compound, we need to use the balanced chemical equation for the combustion of hydrocarbons:

(x + y/4 - z/2)Oxygen → xCarbon dioxide + y/2water

From the equation, we can see that each mole of water produced in the combustion reaction corresponds to y/2 moles of hydrogen in the original compound.

Since we now know that 0.0213 mol of water were produced, we can calculate the moles of hydrogen in the compound:

moles of hydrogen = (2 mol of water / y mol of hydrogen) x 0.0213 mol of water

moles of hydrogen = 0.0426 mol / y

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Answer:

Explanation:

100/56 = 1.79 moles MgS

56 came from the periodic table for Mg and S