1. Consider the following thermochemical reaction for kerosene:
2 C12H26(l) + 37 O2(g)  24 CO2(g) + 26 H2O(l) + 15,026 kJ
(a) When 21.3 g of CO2 are made, how much heat is released?
(b) If 500.00 kJ of heat are released by the reaction, how grams of C12H26 must have been consumed ?
(c) If this reaction were being used to generate heat, how many grams of C12H26 would have to be reacted to generate
enough heat to raise the temperature of 750g of liquid water from 10oC to 90oC?
2. Consider the reaction: NaNO3(s) + H2SO4(l) → NaHSO4(s) + HNO3(g) ΔH° = 21.2 kJ
How much heat must absorbed by the reaction system to convert 100g of NaNO3 into NaHSO4(s)?
3. What is the enthalpy change when 49.4 mL of 0.430 M sulfuric acid reacts with 23.3 mL of 0.309 M potassium
hydroxide?
3.
H2SO4(aq) + 2KOH(aq) → K2SO4(aq) + 2H2O(l) ΔH° = –111.6 kJ/mol

Answer:

0.0063 mol

Explanation:

Step 1: Write the balanced combustion equation

C₈H₁₈(l) + 12.5 O₂(g) ⇒ 8 CO₂(g) + 9 H₂O(g)

Step 2: Establish the appropriate molar ratio

According to the balanced equation, the molar ratio of C₈H₁₈ to CO₂ is 1:8.

Step 3: Calculate the number of moles of C₈H₁₈ needed to produce 0.050 moles of CO₂

0.050 mol CO₂ × 1 mol C₈H₁₈/8 mol CO₂ = 0.0063 mol C₈H₁₈

Answer:  inference because she drew a conclusion based on evidence.

why?:

Because the evidence was that she heard the crashing sound, and then when she came into her room saw the broken window and baseball.

It was not an observation because she did not directly see the baseball going through the window

b) (√)

c)(✓)

hsjdhfjdkskkshd

Answer:

[tex]\boxed {\boxed {\sf 8.10 \ L}}[/tex]

Explanation:

This question asks us find the volume of a gas sample given a change in temperature. Since the pressure remains constant, we only are concerned with the variables of temperature and volume.

We will use Charles's Law. This states the volume of a gas is directly proportional to the temperature of a gas. The formula is:

[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]

The gas starts at a volume of 2.70 liters and a temperature of 25.0 degrees Celsius.

[tex]\frac {2.70 \ L}{25.0 \textdegree C}=\frac{V_2}{T_2}[/tex]

The temperature is increased to 75.0 degrees Celsius, but the volume is unknown.

[tex]\frac {2.70 \ L}{25.0 \textdegree C}=\frac{V_2}{75.0 \textdegree C}[/tex]

We are solving for the volume at 75 degrees Celsius, so we must isolate the variable V₂.

It is being divided by 75.0 °C. The inverse operation of division is multiplication, so we multiply both sides of the equation by 75.0 °C.

[tex]75.0 \textdegree C *\frac {2.70 \ L}{25.0 \textdegree C}=\frac{V_2}{75.0 \textdegree C} * 75.0 \textdegree C[/tex]

[tex]75.0 \textdegree C *\frac {2.70 \ L}{25.0 \textdegree C}= V_2[/tex]

The units of degrees Celsius (° C) cancel.

[tex]75.0 *\frac {2.70 \ L}{25.0}= V_2[/tex]

[tex]75.0 *0.108 \ L = V_2[/tex]

[tex]8.1 \ L = V_2[/tex]

The original measurements have 3 significant figures, so our answer must have the same. Currently, the answer has 2. If we add another 0, the value of the answer does not change, but the number of sig figs does.

[tex]8.10 \ L = V_2[/tex]

The volume of this gas sample at 75.0 degrees Celsius is 8.10 Liters.

Answer:

Mass=Moles × RFM

Mass= 0.28M× 164

Mass= 45.92 grammes

Stalactites and stalagmites form as ________ precipitates out of the water evaporating in underground caves.

Group of answer choices

hydrochloric acid

sodium bicarbonate

calcium carbonate

sodium chloride

sodium hydroxide

Answer:

calcium carbonate

Explanation:

A stalactite is an icicle-looking mould that is formed by the precipitation of natural minerals as a result of water dripping from the ceiling, hanging from a cave.

A stalagmites in the other hand, grows upwards and is also a mound that is formed by the deposits of minerals gotten by the water dripping on the floor of a cave.

Therefore, stalactites and stalagmites form as calcium carbonate precipitates out of the water evaporating in underground caves.

Answer:

a. 0.7119 g

Explanation:

To solve this question we need to know that all carbon of the compound will react producing CO2 and all Hydrogen producing H2O.

Thus, we can find the mass of C and the mass of H and by difference regard to the 2.584g of the compound we can find the mass of oxygen as follows:

Moles CO2 = Moles C -Molar mass: 44.01g/mol-

5.874g CO2 * (1mol/44.01g) = 0.1335 moles CO2 = 0.1335 moles C

Mass C -Molar mass: 12.01g/mol-:

0.1335 moles C * (12.01g /mol) = 1.6030g C

Moles H2O -Molar mass: 18.01g/mol-

2.404gH2O * (1mol / 18.01g) = 0.1335 moles H2O * (2mol H / 1mol H2O) = 0.267 moles H

Mass H -Molar mass: 1g/mol-

0.267 moles H * (1g/mol) = 0.2670g H

Mass Oxygen =

Mass O = 2.584g compound - 1.6030g C - 0.2670g H

Mass O = 0.714g O ≈

Answer:

0.93 M

Step-by-step Explanation:

First, we have to calculate the molar mass (MM) of ZnSO₄ by using the molar mass of each chemical element:

MM(ZnSO₄) = 65.4 g/mol Zn + 32 g/mol S + (16 g/mol x 4) = 161.4 g/mol

Then, we divide the mass of ZnSO₄ into its molar mass to obtain the number of moles:

moles ZnSO₄ = mass/MM = 150 g/(161.4 g/mol)= 0.93 mol

Since the molarity of a solution expresses the number of moles of solute per liter of solution, we calculate the molarity (M) as follows:

M = moles ZnSO₄/1 L =  0.93 mol/1 L = 0.93 M

Answer:

Temperature affects the kinetic energy in a gas the most, followed by a comparable liquid, and then a comparable solid. The higher the temperature, the higher the average kinetic energy, but the magnitude of this difference depends on the amount of motion intrinsically present within these phases.

Explanation:

Liquids have more kinetic energy than solids. When a substance increases in temperature, heat is being added, and its particles are gaining kinetic energy. Because of their close proximity to one another, liquid and solid particles experience intermolecular forces. These forces keep particles close together.

Answer:

The net ionic equation shows the actual reaction more clearly and closer to reality because it writes soluble ionic compounds as the ions and then cancel the spectator ions not involved in the chemical reaction . The net ionic equation results shows the actual chemical reaction taking place.

The net ionic equation for for 2AgF(aq) + k₂S = Ag₂S (s) + 2KF(aq) will be; 2 Ag⁺(aq) + S²⁻(aq) → Ag₂S(s).

To write the net ionic equation for the reaction, we first need to write the balanced molecular equation and then convert it into the ionic equation before finally identifying the net ionic equation.

Write the balanced molecular equation:

2 AgF(aq) + K₂S(aq) → Ag₂S(s) + 2 KF(aq)

In this reaction, silver fluoride (AgF) reacts with potassium sulfide (K₂S) to produce silver sulfide (Ag₂S) and potassium fluoride (KF).

Write the complete ionic equation:

In the complete ionic equation, we separate all the aqueous species (dissociated ions) into their individual ions. Only the solid (s) and gas (g) compounds remain unchanged.

2 Ag⁺(aq) + 2 F⁻(aq) + 2 K⁺(aq) + S²⁻(aq) → Ag₂S(s) + 2 K⁺(aq) + 2 F⁻(aq)

Identify the spectator ions and then write the net ionic equation:

The spectator ions are the ions that do not participate in the actual chemical reaction and remain the same on both sides of the equation. In this reaction, the potassium ions (K⁺) and fluoride ions (F⁻) are spectator ions because they appear on both sides of the equation unchanged.

Net ionic equation:

2 Ag⁺(aq) + S²⁻(aq) → Ag₂S(s)

The net ionic equation shows only the species that actively participate in the chemical reaction. In this case, the silver ions (Ag⁺) and sulfide ions (S²⁻) are the ones involved in forming the silver sulfide (Ag₂S) precipitate.

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--The given question is incomplete, the complete question is

"Write the net ionic equation for this reaction. 2AgF(aq) + k₂S = Ag₂S (s) + 2KF(aq)."--

Answer:

a. 599 cm³

b. 1.49 g/cm³

Explanation:

Volume is the amount of space an object occupies. Since this is a brick, the object is a rectangular prism. The formula for the volume of a rectangular prism is the product of length, width, and height.

[tex]V= l *w*h[/tex]

The brick's length (l) is 13.77 centimeters, the width (w) is 8.50 centimeters, and the height (h) is 5.12 centimeters. Substitute these values into the formula.

[tex]V= 13.77 \ cm * 8.50 \ cm * 5.12 \ cm[/tex]

Multiply the numbers together.

[tex]V= 117.045 \ cm^ 2* 5.12 \ cm[/tex]

[tex]V= 599.2704 \ cm^3[/tex]

The original measurements have at least 3 significant figures, so our answer must have 3. For the number we calculated, that is the ones place. The 2 in the tenths place tells us to leave the 9 in the ones place.

[tex]V \approx 599 \ cm^3[/tex]

[tex]\bold {The \ volume \ of \ the \ brick \ is \ approximately \ 599 \ cubic \ centimeters}}[/tex]

Density is the amount of matter in a specified space. The formula for density is mass over volume.

[tex]d= \frac{m}{v}[/tex]

The mass of the brick is 895.3 grams and we just found the volume to be 599.2704 cubic centimeters. Substitute the values into the formula.

[tex]d= \frac{895.3 \ g}{599 \ cm^3}[/tex]

Divide.

[tex]d= 1.494657763 \ g/cm^3[/tex]

Round to three significant figures. For the number we calculated, that is the hundredth place. The 4 in the thousandth place tells us to leave the 9 in the hundredth place.

[tex]d \approx 1.49 \ g/cm^3[/tex]

[tex]\bold {The \ density\ of \ the \ brick \ is \ approximately \ 1.49 \ grams /cubic \ centimeters}}[/tex]

Answer:

Every atom of a given element has the same number of protons

The protons in the nucleus of the helium atom are held together by a force called the strong nuclear force.

Explanation:

Atoms are composed of electrons, protons and neutrons. The electron is negatively charged, protons are positively charged and the neutrons have no charge.

Electrons are found in shells while protons are found inside the atomic nucleus. Similar to electrostatic forces between electron and proton, protons of helium are held together by a strong nuclear blinding force.

Note that, all isotopes must have the same atomic number. This shows that they are all the same atom changed by differences in number of neutrons.

Answer:

1860g.

Explanation:

It is known that the molar mass of C2H6O2 is 62.08 g/mol.,

Now to  solve for the number of moles of solute, one must multiply both

sides by the volume:

moles of solute = (6.00 M)(5.00 L) = 30.0 mol

Notice since the definition of molarity is mol/L, the

product M × L gives mol, a unit of amount.

Use the molar  mass of C3H8O3, one can convert mol to g:

Mass m =30 mol × 62.08 g/mol

m = 1860g.

Hence, there are 1,860 g of C2H6O2 in the specified amount of

engine coolant.

Answer:

c9h8o2

Explanation:

The molecule which has 9 carbon atom is [tex]C_{9} H_{8} O[/tex](cinnamaldehyde).

 More than one atoms make up a molecule. If they have more than one atom, atoms could be the same for example, an oxygen molecule contains two oxygen atoms) as well as different (for example, a hydrogen molecule contains two hydrogen atoms.

Cinnamaldehyde is a kind of organic chemical with the formula C6H5CH=CHCHO and the formula C6H5CH=CHCHO. It's mostly the trans isomer that's found in nature.

It is known that the number of carbon atom is 9 hence molecule will be cinnamaldehyde

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Answer:

The correct equation is "[tex]\frac{[Ni(H_2O)_3 (NH_3)]^{2+}}{[Ni(H_2O)_4]^{2+} [NH_3]}[/tex]".

Explanation:

According to the question,

Throughout an aqueous solution, [tex]Ni^{2+}[/tex] exist as [tex][Ni(H_2O)_4]^{2+}[/tex]

So,

⇒ [tex][Ni(H_2O)_4]^{2+} + 4NH_3 \rightleftharpoons [Ni(NH_3)_4]^{2+} + H_2O[/tex]

⇒ [tex]K_f = \frac{[Ni(NH_3)_4]^{2+}}{[Ni(H_2O)_4^{2+}] [NH_3]^4}[/tex]

Here, we have excluded [tex][H_2O][/tex] as concentration of water will be const.

Now,

This formation of [tex][Ni(NH_3)_4]^{2+}[/tex] proceeds via several steps,

Step 1:

⇒ [tex][Ni(H_2O)_4]^{2+}+NH_3 \rightleftharpoons [Ni(H_2O)_3 (NH_3)]^{2+} + H_2O[/tex]

⇒ [tex]K_1 = \frac{[Ni(H_2O)_3 (NH_3)]^{2+}}{[Ni(H_2O)_4]^{2+} [NH_3]}[/tex]

Answer:

Formic acid

Sodium formiate

Explanation:

To determine acid or base that can generate a buffer solution with pH around 3.5, we have to think in the acid whose pKa = pH.

Although we have to also think in buffer capacity, a measure which can cause a change of 1 pH unit in 1 L of solution.

Buffer capacity does not only depend on the concentration of its components but also of the relationship between that concentrations.

When pH = pKa, buffer capacity is maximum which means that the concentration of conjugated species is the same and the ability to oppose pH changes is maximum.

One example with pH = pKa or nearly if:

COOH⁻  + Na⁺ →  NaCOOH

HCOOH  +  H₂O  →  COOH⁻  + H₃O⁺     Ka: 1.8×10⁻⁴

pKa = 3.74

Answer:

2.5 × 10² L

Explanation:

Step 1: Given and required data

Step 2: Convert 25 °C to Kelvin

We will use the following expression.

K = °C + 273.15 = 25 + 273.15 = 298 K

Step 3: Calculate the volume (V) of the balloon

We will use the ideal gas equation.

P × V = n × R × T

V = n × R × T / P

V = 9.7 mol × (0.0821 atm.L/mol.K) × 298 K / 0.955 atm = 2.5 × 10² L

Answer:

See explanation

Explanation:

The relationship between the activation energy and rate of reaction is best captured by the Arrhenius equation;

k= Ae^-Ea/RT

Where;

k= rate constant

A= pre-exponential factor

Ea=activation energy

R= gas constant

T= temperature

We can see from the foregoing that, as the activation energy increases, the rate of reaction decreases and vice versa. reactions that have a very high activation energy are markedly slow.

Since the activation energy for the malonic acid reaction is found to be greater than the activation energy for the tartaric acid reaction, then the rate of the malonic acid reaction(k) will be slower than that of the tartaric acid reaction.

The study of chemistry and bonds is called chemistry. There are two types of elements metal and nonmetals.

The correct answer is mentioned below.

The equation is as follows:-

[tex]k= Ae^{-Ea/RT[/tex] Where;

We can see from the foregoing that, as the activation energy increases, the rate of reaction decreases and vice versa. reactions that have very high activation energy are markedly slow. Since the activation energy for the malonic acid reaction is found to be greater than the activation energy for the tartaric acid reaction, then the rate of the malonic acid reaction(k) will be slower than that of the tartaric acid reaction.

Hence, the correct answer is mentioned above.

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Explanation:

elements are carbons and hydrogen

Answer:

Carbon and Hydrogen.

Explanation:

It’s in the name Hydro (H) Carbon (C)

Explanation:

since there are no lone pairs on the central atom, the shape will be tetrahedral

Ribose is a reducing sugar. A reducing sugar is a carbohydrate that can undergo a redox reaction, in which it donates electrons to another chemical species.

This is usually observed when the sugar opens its ring structure to form an aldehyde or ketone functional group.

Ribose, a five-carbon sugar, can form an open-chain structure with an aldehyde functional group. In this form, it can donate electrons and act as a reducing agent in certain chemical reactions, such as the reduction of other compounds like Benedict's reagent during laboratory tests for reducing sugars.

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Solution :

Spontaneous Process

A spontaneous process is defined as the process that occurs without the help of any external aid or inputs. A spontaneous process is a natural process which occurs naturally in the environment.

Non Spontaneous process

A non spontaneous process is a process which does not occur naturally. Some inputs are provided for the process to occur. Energy from external source is applied into the process to start the process.

The following processes are :

1. Melling of ice   ---- Spontaneous

2 Rusting of iron  --- Spontaneous

3. Marble going down the spiral.   --- spontaneous

4. Going up the hill  ---- Non spontaneous

5. Keeping the food fresh from spoilage​  --- Non spontaneous

Answer:

62.5 ml of 0.032 M  KMnO₄ are required to react with 50.0 ml of 0.100 molar H₂C₂O₄ in the presence of excess H₂SO₄

Explanation:

The balanced reaction is:

2 KMnO₄ + 5 H₂C₂O₄ + 3 H₂SO₄ → K₂SO₄ + 2 MnSO₄ + 8 H₂O + 10 CO₂

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Molarity or Molar Concentration is the number of moles of solute that are dissolved in a certain volume.

The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:

[tex]Molarity=\frac{number of moles of solute}{volume}[/tex]

Molarity is expressed in units [tex]\frac{moles}{liter}[/tex]

In this case, 50 mL (0.05 L) of 0.1 M H₂C₂O₄ react. So, replacing the data in the definition of molarity:

[tex]0.1 M=\frac{number of moles of solute}{0.05 L}[/tex]

Solving:

number of moles of solute= 0.1 M*0.05 L

number of moles of solute= 0.005 moles

So, 0.005 moles of H₂C₂O₄ react.  Then you can apply the following rule of three: if by stoichiometry 5 moles of H₂C₂O₄ react with 2 moles of KMnO₄, 0.005 moles of H₂C₂O₄ react with how many moles of KMnO₄?

[tex]moles of KMnO_{4} =\frac{0.005moles of H_{2} C_{2} O_{4}* 2moles of KMnO_{4} }{5moles of H_{2} C_{2} O_{4} }[/tex]

moles of KMnO₄= 0.002 moles

Knowing that the molarity of KMnO₄ is 0.032 M, replacing in its definition and solving:

[tex]0.032 M=\frac{0.002 moles}{volume}[/tex]

[tex]volume=\frac{0.002 moles}{0.032 M}[/tex]

volume= 0.0625 L= 62.5 mL

62.5 ml of 0.032 M  KMnO₄ are required to react with 50.0 ml of 0.100 molar H₂C₂O₄ in the presence of excess H₂SO₄

Answer:

The volume will be 185.83 mL.

Explanation:

Gay-Lussac's law indicates that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases. Gay-Lussac's law can be expressed mathematically as follows:

[tex]\frac{P}{T} =k[/tex]

Where P = pressure, T = temperature, k = Constant

Boyle's law says that the volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure. Boyle's law is expressed mathematically as:

P*V=k

Where P = pressure, V = volume, k = Constant

Finally, Charles's Law consists of the relationship that exists between the volume and the temperature of a certain quantity of ideal gas, which is kept at a constant pressure. For a given sum of gas at a constant pressure, as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases because the temperature is directly related to the energy of the movement of the gas molecules. .

In summary, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:

[tex]\frac{V}{T} =k[/tex]

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

[tex]\frac{P*V}{T} =k[/tex]

Studying two different states, an initial state 1 and a final state 2, it is satisfied:

[tex]\frac{P1*V1}{T1} =\frac{P2*V2}{T2}[/tex]

In this case:

Replacing:

[tex]\frac{720 torr*256 mL}{308 K} =\frac{950 torr*V2}{295 K}[/tex]

Solving:

[tex]V2= \frac{295K}{950 torr} *\frac{720 torr*256 mL}{308 K}[/tex]

V2= 185.83 mL

The volume will be 185.83 mL.

Answer:

0.696 m

Explanation:

We'll begin by calculating the number of mole in 16.7 g of C₆H₁₂O₆. This can be obtained as follow:

Mass of C₆H₁₂O₆ = 16.7 g

Molar mass of C₆H₁₂O₆ = (6×12) + (12×1) + (6×16)

= 72 + 12 + 96

= 180 g/mol

Mole of C₆H₁₂O₆ =?

Mole = mass / molar mass

Mole of C₆H₁₂O₆ = 16.7 / 180

Mole of C₆H₁₂O₆ = 0.093 mole

Next, we shall convert 133.6 g of water to Kg. This can be obtained as follow:

1000 g = 1 Kg

Therefore,

133.6 g = 133.6 g × 1 Kg / 1000 g

133.6 g = 0.1336 Kg

Thus, 133.6 g is equivalent to 0.1336 Kg.

Finally, we shall determine the molality of the solution. This can be obtained as illustrated below:

Mole of C₆H₁₂O₆ = 0.093 mole

Mass of water = 0.1336 Kg

Molality =?

Molality = mole / mass of water (in Kg)

Molality = 0.093 / 0.1336

Molality = 0.696 m

Therefore, the molality of the solution is 0.696 m

TRUE

Explanation:

*not sure about this answer

Answer:

a. True

Explanation:

There is strong inhibition of Carbon Anhydrase by Aceta-zolamide Carbonic Anhydrase. The drug acetazolamide is used as diuretic which increase the urine production in human body. It lowers pressure in eye in glaucoma.