Select the correct answer. Which is true according to the law of conservation of energy? A. In a closed system, the total amount of energy in the universe keeps on changing. B. The supply of energy is limited, so it is essential to conserve it. C. In a closed system, energy can be created and destroyed. D. In a closed system, energy cannot be used faster than it is created. E. In a closed system, the total energy always remains constant.

Answer:

Yes they are

Explanation:

Answer:

Fossils are traces of ancient life. Scientists use fossils to gather information about the lives and evolutionary relationships of organisms, for understanding geological change.

Answer:

it is the British imperial and united states customary systems

No, not all antigens are foreign substances.

An antigen is any substance that can trigger an immune response, including the production of antibodies. Some antigens are naturally present in the body and are called "self" antigens which are usually not harmful, but in some cases, the immune system can mistakenly recognize them as foreign and attack them which can lead to autoimmune diseases.

Antigens bind together with antibodies and promote the elimination of harmful pathogens present in the body. They alert other parts of the immune system to take over which helps to neutralize the threat from pathogens.

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Answer:

they don't depend on the temperature

Answer: Molecular formula is S2F4

Explanation:   Assume mass of sample is 100 g.

Then mass of S is 45.77 g and amount of substance is

n = m/M = 45.77 g / 32.07 g/mol = 1.427 mol

MAss of F is 54.23 g and n = 54.23 g / 19 g/mol = 2.854

n(S( : n(F) = 1.427  : 2.854  | : 1.427   gives proportion

n(S) : n(F) = 1:2 , empirical formula is also (SF2)x

Now M(SF2) = 32.07 + 2·19 = 70.07 g/mol

x = 140.12 / 70.07 = 2  

Answer: The Equator because it divides the Earth into the Northern and Southern hemispheres.

Explanation:

Heat transfer is the movement of thermal energy from a temperature that is higher to one that is lower.

The energy that exists in a system and controls its temperature is known as thermal energy. Heat is thermal energy in motion. Thermodynamics is a comprehensive field of physics that examines how heat and work are transferred between diverse systems.

The energy that results from atoms and molecules moving around within a substance is known as thermal energy, often known as heat. When these particles move more quickly, heat is produced. Geothermal energy is the earth's heat energy. Energy held within motion is referred to as motion energy.

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Answer:

Explanation:

Given pinene has a (temperature, vapor pressure) relation (K, torr) = {(373, 135), (429, 760)}, you want the heat of vaporization in kJ/mol and the vapor pressure at room temperature (23 °C).

The Clausius–Clapeyron equation can be used to find the heat of vaporization:

  [tex]\ln{P}=-\dfrac{\Delta H_{\text{vap}}}{R}\left(\dfrac{1}{T}\right)+C[/tex]

Solving for ∆H, we find ...

  [tex]\Delta H_{\text{vap}}=-\dfrac{R\cdot\ln{\dfrac{P_1}{P_2}}}{\dfrac{1}{T_1}-\dfrac{1}{T_2}}\\\\\\\Delta H_{\text{vap}}=-\dfrac{8.314\cdot\ln{\dfrac{760}{135}}}{\dfrac{1}{429}-\dfrac{1}{373}}\approx 41052.8[/tex]

The heat of vaporization of pinene is about 41 kJ/mol.

Rearranging the above equation to give P1, we have ...

  [tex]\ln{\dfrac{P_1}{P_2}}=-\dfrac{\Delta H_\text{vap}}{R}\left(\dfrac{1}{T_1}-\dfrac{1}{T_2}\right) \\\\\\P_1=P_2\cdot e^{-\frac{\Delta H_\text{vap}}{R}\left(T_1^{-1}-T_2^{-1})}[/tex]

Using the same P2 and T2 as above, we find the vapor pressure at room temperature (296.15 K) to be ...

  P1 ≈ 4.349 . . . . . torr

The vapor pressure of pinene at room temperature is about 4 torr.

Answer:

Your answer would be a buffer, they control pH levels.

Explanation:

Buffer is a substance that reacts with an acid or a base to control pH. Hence, option A is correct.

pH is a measure of how acidic/basic water is.

Buffers are solutions that resist a change in pH after adding an acid or a base. Buffers contain a weak acid (HA) and its conjugate weak base (A−).

Hence, option A is correct.

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Answer:

A chemical reaction

Explanation:

You're doing acid-alkali. Acid is like a ph.

Titration is a method used to prepare salts if the reactants are soluble. Concentration and volumes of reactants can be calculated from titrations. The concentration of an acid or alkali can be calculated by carrying out an experiment called a titration.

We have that for the Question "Today we are going to perform a titration. What is an acid-alkali titration?" it can be said that

From the question we are told

Today we are going to perform a titration. What is an acid-alkali titration?

a) A measurement apparatus

b) An analytic method

c) A chemical reaction

Generally  

acid-alkali titration is a popular chemical reaction that is used to obtain salts and this method is also used to determine many other variables of the reactants

Therefore

An acid-alkali titration is a

chemical reaction

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Answer:

The atomic radius of a chemical element is the measure of the size of its atoms, usually the mean or typical distance from the centre of the nucleus to the boundary of surrounding shells of electrons

Hope it helps :)

Answer:

Acyclic or Open-chain compounds. Cyclic or Closed-chain compounds.

Answer:

D

Explanation:

The energy of the reactants is higher than the  energy of the products.

Answer:

I don't understand what to do with this

The sections of the heating curve illustrate this process Section A followed by B. Therefore, option D is correct.

The term heating curve is defined as the graphical representation of the correlation between heat input and the temperature of a substance.

At section, A solid Ice at temperature 0°C can heat  for about 10 mins and all the energy generated from heating up the ice is used to split the bonds which binds the ice together as a solid.

At Section, B the liquid water at 100°C covert to vapor because the heat energy required here split the bond between the water molecules then they are move in random directions as vapor.

Thus, option D is correct.

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Your question is incomplete, probably your question was

As a sample of water is heated, the energy is used to overcome the attractions between the molecules so that they are no longer held close together and can move in random directions. Then, the kinetic energy of its molecules increases. Which sections of the heating curve illustrate this process?

As a sample of water is heated, the energy is - 1

Image is attach below

Answer:

0.667 L

Explanation:

From the question given above, the following data were obtained:

Initial volume (V₁) = 250 mL

Initial concentration (C₁) = 12 M

Final concentration (C₂) = 4.5 M

Final volume (V₂) =?

The final volume of the solution can be obtained by using the dilution formula as illustrated below:

C₁V₁ = C₂V₂

12 × 250 = 4.5 × V₂

3000 = 4.5 × V₂

Divide both side by 4.5

V₂ = 3000 / 4.5

V₂ = 667 mL

Finally, we shall convert 667 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

667 mL = 667 mL × 1 L / 1000 mL

667 mL = 0.667 L

Thus, the volume of the solution prepared is 0.667 L

Answer:

109.02 grams

Explanation:

Multiply the molar mass of sulfur by the moles: 3.4 * 32.065 = 109.02 grams

Answer:

Electrons

Explanation:

"An electron is a negatively charged particle that orbits the nucleus of an atom."

"Electrons are negatively charged particles arranged in orbits around the nucleus of an atom"

Answer:

First solution pH = 1.32

Second solution pH = 9.44

Explanation:

For the first solution:

Which is the same as saying 4.78 x 10⁻² M is [H⁺].

Knowing [H⁺], we can now calculate the pH:

As for the second solution, we can calculate the pH by keeping in mind the relationship between pOH and pH:

Answer:

potassium carbonate -> potassium oxide + carbon dioxide

Explanation:

remember to look at your periodic table, located each element so in this case you would locate k,c and o which are potassium, carbon and oxygen. From there you use nomenclature rules to get your answer.

a) The strongest metal on the planet is tungsten.

When it comes to tensile strength, tungsten tops all other metals. One of the strongest metals known to man, tungsten has an ultimate strength of 1510 Megapascals.

In addition to having the greatest melting point of any unalloyed metal, tungsten boasts greater strength. Tungsten is frequently employed in electrical and military applications due to its strength.

Tin is a malleable, silvery-white metal that is highly flammable at ambient temperature.

Metal malleability is a complex subject. There is no objective test available to measure this feature, as we previously stated. We most frequently test it for hardness.

The most malleable and ductile metals are gold and silver. Pure gold and silver are too soft to be used to create items that will keep their shape.

Metals may be molded into different shapes, such as thin sheets or foils, without breaking or shattering because they are malleable. They are also ductile, making it simple to draw them into wires.

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Given :

Molarity of sulfuric acid solution is 3.0 M.

Amount of sulfuric acid present in solution is 9.809 g.

To Find :

The volume of solution.

Solution :

We know, molarity is given by :

[tex]Molarity = \dfrac{number \ of \ moles \times 1000}{Volume\ ( ml )}\\\\M = \dfrac{w \times 1000}{M.M \times V}\\\\3 = \dfrac{9.809\times 1000}{98.09 \times V}\\\\V = \dfrac{1000}{10\times 3}\ ml\\\\V = 33.33 \ ml[/tex]

Therefore, volume required is 33.33 ml .

Answer:

So 0.39 moles of oxygen are produced in 14 g of water. So that's it.

Explanation:

Answer:

The pressure inside the container will be 3.3 atmospheres

Explanation:

The relationship between the temperature and pressure of a gas occupying a fixed volume is given by Gay-Lussac's law which states that the pressure of a given amount of gas is directly proportional to its temperature on the kelvin scale when the volume is kept constant.

Mathematically, it expressed as: P₁/T₁ = P₂/T₂

where P₁ is initial pressure, T₁ is initial temperature, P₂ is final pressure, T₂ is final temperature.

The above expression shows that the ratio of the pressure and temperature is always constant.

In the given question, the gas in the can attains the temperature of its environment.

P₁ = 3 atm,

T₁ = 25 °C = (273.15 + 25) K = 298.15 K,

P₂ = ?

T₂ = (55 °C = 273.15 + 55) K = 328.15 K

Substituting the values in the equation

3/298.15 = P₂/328.15

P₂ = 3 × 328.15/298.15

P₂ = 3.3 atm

Therefore, the pressure inside the container will be 3.3 atmospheres

Answer:

101 L

Explanation:

35.0 g KOH ÷ 56.09 g/mol KOH × (1 mol H2O/ 1 mol KOH) × 18 g/mol H2O = 11.2 g H2O

35.0 g HCl ÷ 36.45 g/mol HCl × (1 mol H2O/ 1 mol HCl) × 18 g/mol H2O = 17.3 g H2O

35.0 g KOH is the limiting reactant

Answer:

The terms azeotropic and zeotropic are opposite to each other. The key difference between azeotropic and zeotropic mixture is that the dew point and bubble point of an azeotropic mixture intersect, whereas the dew point and bubble point of a zeotropic mixture are distinguishable.

Explanation:

The mass of [tex]IF_5[/tex] that would be in a 15.88 L sample at 378 K and 0.935 will be 106.51 grams.

The problem can be solved by first using the ideal gas equation to know the number of moles of the gas that is present.

PV = nRT

P = 0.935, V = 15.88 L, T = 378 K, R = 0.082

Making n the subject of the formula:

n = PV/RT

  = (0.935x15.88)/(0.082x378)

   = 0.48 moles of the gas

Recall that, mass = mole x molar mass

The molar mass of [tex]IF_5[/tex] is 221.89 g/mol

Mass of 0.48 moles [tex]IF_5[/tex] = 0.48 x 221.89

                                       = 106.51 grams

In other words, the mass of [tex]IF_5[/tex] that would be in a 15.88 L sample at 378 K and 0.935 is 106.51 grams.

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The half-life of gold-198 is 2.77 days

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Answer:

To determine the volume of the solution in milliliters, we need to know the mass of CuNO3 and the concentration of the solution.

Given that 3.38g of CuNO3 is dissolved in water to make a 0.220 M solution, we can use the following formula to calculate the volume of the solution:

Volume = (Mass of CuNO3) / (Concentration of solution)

Plugging in the given values, we have:

Volume = (3.38 g) / (0.220 M)

Converting the mass to grams and the concentration to moles/liter, we have:

Volume = (3.38 g) / (0.220 mol/L)

Calculating, we find that the volume of the solution is approximately 15.36 liters.

To convert the volume to milliliters, we can multiply the volume in liters by 1000. In this case, the volume in milliliters is 15,360 ml.

Therefore, the volume of the solution in milliliters is approximately 15,360 ml.

Explanation: