What is a reaction rate?

Answer:

5.64×10²³ atoms C

Explanation:

Convert moles of H to moles of C:

2.81 mol H × (2 mol C / 6 mol H) = 0.937 mol C

Convert moles of C to atoms of C:

0.937 mol C × (6.02×10²³ atoms C / mol C) = 5.64×10²³ atoms C

Answer:

3.75 grams of methane

Explanation:

Given parameters:

Mass of oxygen gas = 5g

Mass of CH₄ = 5g

Unknown parameters:

Amount of excess reactant = ?

Solution

In order to find the amount of leftover reactant we need to know  the reactant that is in excess and in limited supply. The amount of reactant in short supply will determine the extent of the reaction.

Now, we need to write the balanced reaction equation:

                   CH₄ + 2O₂ → CO₂ + 2H₂O

We first find the number of moles of the reactants.

Number of moles of methane = [tex]\frac{mass}{molar mass}[/tex]

Number of moles of methane =  [tex]\frac{5}{16}[/tex] = 0.3125mole

Number of moles of oxygen = [tex]\frac{5}{32}[/tex] = 0.156mole

    From the equation:

      1 mole of methane reacts with 2 moles of oxygen gas

      x moles of methane reacts with 0.156moles of oxygen gas

                2x = 0.156

                  x = 0.078moles

We see that the methane is in excess and oxygen gas is in short supply in the reaction.

The amount of excess methane = 0.3125 - 0.078 = 0.2345moles

Now we convert it to mass:

  Mass = number of moles x molar mass = 0.2345 x 16 = 3.75grams

Answer:

3.75 grams of methane

Explanation:

Got it right on the exam

B. 3.62 m3

PV = nRT

(0.1185 atm)V = (17 mol)(0.0821 L•atm/K•mol)(307.15 K)

0.1185V = 428.689

V = 3617.63 L

so for cubic meters, 1,000 liters equals 1 m^3. Simply divide the answer by 1,000.

The volume that this would occupy is 3.62 m^3.

volume is the measure of the capacity that an item holds. for example, if a cup can hold one hundred ml of water up to the brim, its volume is said to be one hundred ml. volume also can be defined as the amount of area occupied by a three-dimensional object.

volume refers to the amount of area the object takes up. In other words, volume is a measure of the size of an object, just like height and width are methods to describe size. If the object is hollow (in other words, empty), volume is the amount of water it can hold.

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Answer:

A) Alloys are mixtures with undefined proportions.

Explanation:

Alloys are different mixtures or different materials with no exact portion size.  

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Answer:

0.0447 moles of Aluminum

Explanation:

Break this down to an ionic equation (which may not exist in the real world but it will give you the mol ratios).

Al2(SO4)3 ===> 2Al^(+3) + 3 SO4^(-2)

Now write the equation showing the actual number of moles of SO4^(-2) present. Indicate the Al moles with an x

Al2(SO4)3 ===> 2Al^(+3) + 3 SO4^(-2)

                                x             0.0670  

Now set  up a proportion

2/x = 3/0.0670                             Cross multiply

2*0.0670 = 3x                              Simplify the left

0.134 = 3x                                     Divide both sides by 3

0.134/3 = 3x/3                              Divide

0.0447 = x

there are 0.0447 moles of Aluminum

Answer: Option (C)

Explanation: Hydrogen and Helium initially, both were present on the earth's atmosphere. But later they were reduced upto a huge extent. Due to the location of earth near to the sun, these gases must have evaporated from the earth's atmosphere. At present the amount of hydrogen and helium is very less.

Thus, the correct answer is option (C).

Answer:

CaCl₂(s) ⟶ Ca²⁺(aq) + 2Cl⁻(aq)

Explanation:

When the calcium chloride dissolves. the calcium and chloride ions leave the surface of the solid and go into solution as hydrated ions.

Answer:

0.666 mol I

Explanation:

0.333 mol CaO(IO₃)₂ × (2 mol IO₃ / mol CaO(IO₃)₂) = 0.666 mol IO₃

0.666 mol IO₃ × (1 mol I / mol IO₃) = 0.666 mol I

Answer:

No reaction.

Explanation:

An Arrhenius base (like NaOH) increases the concentration of hydroxide ions present in the solution.

If you add Rb to an aqueous solution of NaOH, you will get an explosion.

However, the Rb does not react with the OH^-. Instead, it reacts rapidly with the water.

2Rb + 2H2O → 2RbOH + H2

So much heat is generated that the hydrogen explodes:

2H2 + O2 → 2H2O

Answer:

A

Explanation:

CH4+O2-CO2+ H20

that mean methane has burn in oxygen to produce CO2

Answer:

D. The nucleus of an atom of lithium splits, resulting in smaller fragments and the release of a large amount of energy.

Explanation:

Fission is the splitting of a nucleus, so this is the only option that involves fission.

A is wrong. Li atoms do not bond to form molecules. Instead, the nuclei are immersed in a sea of electrons.

B is wrong. The joining of two nuclei is fusion.

C is wrong. Adding an electron to an atom of lithium is not a nuclear reaction.

The nucleus of an atom of lithium splits, resulting in smaller fragments and the release of a large amount of energy. Therefore, option D is the correct answer.

Nuclear fission is a reaction in which a heavy nucleus splits into two or more smaller nuclei. Some characteristics features of nuclear fission are,

Thus, we can conclude that, in nuclear fission lithium atom is splits into smaller fragments with the release of a large amount of energy. Therefore, option D is the correct answer.

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Answer:

B.

Explanation:

If the concentration of acid is decreased the reaction rate will slow down as the hydrogen ion concentration will decrease.

Answer:

B. The reaction rate will slow down.

Explanation:

As concentration increases, rate of the reaction will increase. When there are more particles present in a system, more collision will take place.

As collision increases, rate of the reaction will increase. Concentration makes the molecules to come closer together thus leading to more collisions.

Rate of the reaction is directly proportional to the reactant collisions.

Orientation of the molecule and molecule possessing enough energy  will lead to increased number of collisions thereby increasing the rate of the reaction .

So, Increasing the concentration of a reactant increases the frequency of collisions between reactants and will, therefore, increase the reaction rate

Answer:

280 mL

Explanation:

Ideal gas law:

PV = nRT

Rearranging:

V / T = nR / P

At constant pressure:

V₁ / T₁ = V₂ / T₂

Substituting values:

250 / (15 + 273) = V / (45 + 273)

V = 276

Rounded to two significant figures, the volume will be 280 mL.

When using the ideal gas law, remember to always use absolute units for temperature, like Kelvin.

Final answer:

The volume of oxygen, initially at 250 ml and 15 degrees Celsius, will increase to approximately 275.5 ml when the temperature is raised to 45 degrees Celsius, according to Charles's Law.

Explanation:

The volume of a quantity of oxygen gas changes with temperature, which can be explained by Charles's Law. This law states that at constant pressure, the volume of a gas is directly proportional to its absolute (Kelvin) temperature. To find the new volume at a higher temperature, you can use the formula V₁/T₁ = V₂/T₂, where V₁ and T₁ are the initial volume and temperature, and V₂ and T₂ are the final volume and temperature.

To apply this to the student's question: The oxygen has an initial volume (V₁) of 250 ml at an initial temperature (T₁) of 15 degrees Celsius, which converts to 288.15 K (Celsius to Kelvin: C + 273.15). The final temperature (T₂) is 45 degrees Celsius or 318.15 K. Applying Charles's Law, we get:

250 ml / 288.15 K = V₂ / 318.15 K

Multiplying both sides by 318.15 K to solve for V₂ gives us:

V₂ = (250 ml * 318.15 K) / 288.15 K

V₂ ≈ 275.5 ml

So, when the temperature is raised to 45 degrees Celsius, the volume of oxygen will be approximately 275.5 ml.

Answer: The volume of gas is 24.9 L. The volume can be calculated using the Ideal Gas Equation which relates the pressure, volume, temperature, and amount of gas to each other.  

Further Explanation

The Ideal Gas Equation is:  

[tex]PV = nRT[/tex]

where:

P - pressure (in atm)

V - volume (in L)

n - amount of gas (in moles)

R - universal gas constant [tex]0.08206 \frac{L-atm}{mol-K}[/tex]

T - temperature (in K)

In the problem, we are given the values:

P = 0.80 atm (2 significant figures)

V =  ?

n = 0.75 moles (2 significant figures)

T = 50.0 degrees Celsius (3 significant figures)

We need to convert the temperature to Kelvin before we can use the Ideal Gas Equation. The formula to convert from degree Celsius to Kelvin is:

[tex]Temperature \ in \ Kelvin = Temperature\ in \ Celsius \ + \ 273.15[/tex]

Therefore, for this problem,

[tex]Temperature\ in \ K = 50.0 +273.15\\Temperature\ in \ K = 323.15[/tex]

Solving for V using the Ideal Gas Equation:

[tex]V = \frac{nRT}{P} \\V = \frac{(0.75\ mol) \ (0.08206 \ \frac{L-atm}{mol - K}) \ (323.15\ K) \ }{0.80 \ atm} \\V = 24.86\ L[/tex]

The least number of significant figures is 2, therefore, the final answer must have only 2 significant figures.  Hence, the volume is 24.9 L.

Learn More

1. Learn more about Boyle's Law https://brainly.com/question/1437490  

2. Learn more about Charles' Law https://brainly.com/question/1421697

3. Learn more about Gay-Lussac's Law https://brainly.com/question/6534668

Keywords: Ideal Gas Law, Volume, Pressure

The volume of a gas at 50.0°C and 0.80 atm, with 0.75 moles of the gas present, is 24.93 L.

The volume of a gas can be calculated using the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin. To calculate the volume, we can rearrange the equation to V = (nRT/P).

Using the given values, n = 0.75 moles, R = 0.08206 L-atm/mol-K, T = 50.0°C + 273.15 = 323.15 K, and P = 0.80 atm, we can plug them into the equation:

V = (0.75 mol x 0.08206 L-atm/mol-K x 323.15 K) / 0.80 atm = 24.93 L

Volume is a measure of the amount of space occupied by a three-dimensional object. It is typically measured in cubic units, such as cubic meters or cubic centimeters. The volume of an object can be calculated using various formulas, depending on the shape of the object. For example, the volume of a cube can be calculated using the formula V = s^3, where V is the volume and s is the length of one side of the cube. Similarly, the volume of a cylinder can be calculated using the formula V = πr^2h, where V is the volume, r is the radius of the base of the cylinder, and h is the height of the cylinder.

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Answer:

the answer is letter d

Polyatomic ions are named similarly to monatomic ions in ionic compounds. No changes are made to the ending of the polyatomic ion. The name of the compound is formed by combining the cation and the anion.

Compounds containing polyatomic ions are named similarly to those containing only monatomic ions, except there is no need to change to an -ide ending, since the suffix is already present in the name of the anion. For example, if we have the compound NaNO3, it is named as sodium nitrate. Similarly, CaCO3 is named as calcium carbonate, and NH4Cl is named as ammonium chloride.

In ionic compounds, polyatomic ions are named similarly to monatomic ions. The ending of the polyatomic ion remains unchanged. The name of the compound is formed by combining the cation and the anion.

For example, in the compound sodium nitrate (NaNO3), the polyatomic ion is nitrate (NO3-). The name of the compound is formed by combining the cation (sodium, Na+) and the anion (nitrate, NO3-).

Similarly, in calcium carbonate (CaCO3), the polyatomic ion is carbonate (CO3^2-). The name of the compound is formed by combining the cation (calcium, Ca^2+) and the anion (carbonate, CO3^2-).

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Answer:

C. 2-methylpropane

Explanation:

There are rules guiding the naming of hydrocarbons. Some of the rules are:

1.) The longest continuous chain is the parent chain:

The longest chain here is made up of 3-carbon atoms which is a propane compound

2.)The carbon atoms are numbered in the parent chain to indicate where branching or substitution takes place.

Here, it is in the second carbon atom in propane.

The branched group is methyl- which is a methane molecule that has lost a hydrogen atom.

This makes ths name of the compound to be:

2-methylpropane

Answer: C.

Explanation:

Answer:

See below

Explanation:

Ca + 2H2O → Ca(OH)2 + H2

The elements involved are:

The numbers of each atom are:

The 2 in front of H2O multiplies everything in the H2O.

Answer:

Hydrogen gas  is evolved at the cathode and chlorine gas at the anode.

Explanation:

The solution will ionise.  Hydrogen ions, H+, will migrate to  the negative cathode ( where the current leaves the solution and chloride ions Cl- will migrate the the positive anode.

In the electrolysis of hydrochloric acid using platinum electrodes, the anode will release chlorine gas, and the cathode will release hydrogen gas.

In the electrolysis of hydrochloric acid, both electrodes (anode and cathode) will be made of platinum. When current is passed through the hydrochloric acid solution, at the anode, chloride ions (Cl-) will be oxidized to form chlorine gas (Cl2), and at the cathode, hydrogen ions (H+) will be reduced to form hydrogen gas (H2). Therefore, the platinum anode will release chlorine gas, and the platinum cathode will release hydrogen gas.

Answer:

0.187kg

Explanation:

Given parameters:

Percentage compostion of bauxite in ore = 54%

Mass of ore = 1kg

Unknown:

Mass of Al that can be extracted from the ore = ?

Solution

Bauxite is an ore of Aluminium. It is made up of several minerals from with aluminium can be extracted in economic amount. Some of these minerals are gibbsite, boehmite, diaspore etc. Let us assume that the ore we are dealing with contains chiefly gibbsite.

The formula of Gibbsite is Al(OH)₃

We know that 54% of the ore is made up of bauxite and the remaining 46% of the ore will form the gangue(not useful part of the ore)>

Let us find the mass of the bauxite contained in the ore:

  Mass of bauxite = [tex]\frac{54}{100}[/tex] x 1kg = 0.54kg

Since we know the mass of bauxite in the ore now, we can estimate the mass of the aluminium in the ore.

First, we find the molar mass of the gibbsite:

Molar mass of Al(OH)₃ = 27 + 3(16 + 1) = 78gmol⁻¹

Atomic mass of aluminium is 27

Mass of aluminium that could be extracted = [tex]\frac{27}{78}[/tex] x 0.54

                                                                       = 0.346 x 0.54

                                                                       = 0.187kg

Answer:

b. LD-75

Explanation:

You give the same dosage of chemicals A and B to a sample of test subjects.

Chemical A kills 75 % of the subjects, while chemical B kills only 25 %.

Chemical A, with LD-75, is more toxic.

LD-75 would be more toxic. Hence, option B is correct.

The quality of being toxic or poisonous.

You give the same dosage of chemicals A and B to a sample of test subjects.

Chemical A kills 75 % of the subjects, while chemical B kills only 25 %.

Chemical A, with LD-75, is more toxic.

Hence, option B is correct.

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Answer:

A - 8

B - 8

C - O

D - 26

E - 30

F - Fe

Explanation:

Use these things:

1. A = Z + N,

where A - mass number,

Z - atomic number,

N - number of neutrons

2. atomic number = number of protons

Answer:

It is C.

Explanation:

The atomic mass = number  of protons + number of neutrons

= 5 + 6 = 11. The number of protons = the number of electrons.

Final answer:

A boron atom with an atomic number of 5 and an atomic mass of 11 contains 5 protons, 5 electrons, and 6 neutrons.

Explanation:

An atom of boron has an atomic number of 5 and an atomic mass of 11. The atomic number tells us that there are five protons in the nucleus of a boron atom. Given that the atomic mass is the sum of the protons and neutrons, and the atomic mass of boron is 11, we can deduce that there must be 6 neutrons (11 - 5 = 6). Boron atoms also have an equal number of electrons as protons when they are neutral. Therefore, the correct composition of a neutral boron atom is 5 protons, 5 electrons, and 6 neutrons.

Boron has two naturally occurring isotopes, boron-10 and boron-11, which differ only in their number of neutrons. Isotopes are variants of the same element that have the same number of protons but a different number of neutrons. Boron's average atomic mass is calculated based on the relative abundance of its isotopes: 20% boron-10 (5 protons and 5 neutrons) and 80% boron-11 (5 protons and 6 neutrons).

Answer:

A. covalent, polar

Explanation:

Water is a(n) covalent molecule, and it easily dissolves polar molecules.

Answer:

Choice A. 0.50 g.

Explanation:

According to the question, the reaction here converts

to

By the Law of Conservation of Mass, matter can neither be created nor destroyed in a chemical reaction. (Shrestha et. al, Introductory & GOB Chemistry, Chemistry Libretexts, 2019.)

In other words, the mass of the reactants, combined, shall be the same as the mass of the products, combined.

What's the mass of the reactants?

[tex]\rm \underbrace{\rm 3.80\;g}_{\mathrm{Cs_2CO_3}} + \underbrace{\rm 1.90\; g}_{\mathrm{HBr}} = 5.70\;g[/tex].

What's the mass of the products?

Let [tex]m(\mathrm{CO_2})[/tex] represent the mass of carbon dioxide produced in this reaction.

The mass of the products will be:

[tex]\rm \underbrace{\rm 5.20\;g}_{\mathrm{CeBr}\text{ and }\mathrm{H_2O}} + \underbrace{m(\mathrm{CO_2})}_{\mathrm{CO_2}}[/tex].

The two masses shall be equal. That is:

[tex]\rm 5.20\; g + \mathnormal{m}(\mathrm{CO_2}) = 5.70\;g[/tex].

[tex]m(\mathrm{CO_2}) = \rm 0.50\;g[/tex].

In other words, by the Law of Conservation of Mass, the mass of carbon dioxide produced in this reaction will be [tex]\rm 0.50\;g[/tex].

Answer:

Explanation:

One of the assumptions of the kinetic molecular theory is that the gas particles are way smaller than the separtion between them and, in consequence, most of the volume in a gas is empty space.

This condition (that most of the volume in a gas is empty space) explains why the gases can be easily compressed: since there are vast unoccupied spaces when the pressure is increased, the particles can approach each other with which the total volume of the gas decreases.

Expandibility, the property of expanding, is the ability that gases have to occupy the entire space of the container in which they are located. The particles then will get separated leaving most of the space empty.

The fact that most of the volume in a gas is empty space means that the volume for a certain amount of particles is much larger than the volume that the same number of particles in a solid will occupy, driving to much lower densities.

Gases exhibit very low density, the ability to mix completely with other gases, and follow Avogadro's hypothesis, all of which support the assumption that a gas is mostly empty space.

Properties of Gases and Empty Space

The properties of gases we observe can indeed support the assumption that most of the volume of a gas is empty space. One key property is the fact that gases have a very low density compared to liquids and solids. This low density occurs because the gas particles, which have mass, make up only a tiny fraction of the gas's volume. The rest is empty space that can be compressed or expand when the pressure or temperature changes.

Another supportive property is the ability of gases to mix completely with one another, without any significant interference from the size of their particles. This behavior also indicates that there is a lot of space between particles, allowing them to move freely and intermingle.

Moreover, Avogadro's hypothesis suggests that equal volumes of all gases, at the same temperature and pressure, contain equal numbers of molecules, thus underscoring the concept of empty space in gases since these molecules occupy negligible space compared to the whole volume.

Answer:

A. 4.

Explanation:

no. of moles (n) = mass/molar mass.

mass = 64.0 g, molar mass = 16.0 g/mol.

∴ no. of moles (n) = mass/molar mass = (64.0 g)/(16.0 g/mol) = 4 mol.

Final answer:

To find the number of moles of methane in 64 grams, divide the mass by the molar mass of methane, which is 16.05 g/mol. The result is approximately 4 moles of CH₄. Option A

Explanation:

To calculate the number of moles in 64 grams of methane (CH₄), we need to use the molar mass of methane as a conversion factor. Methane has a molar mass of approximately 16.05 g/mol (carbon is 12.01 g/mol and hydrogen is approximately 1.008 g/mol × 4). Therefore, the calculation is as follows:

Number of moles of CH₄ = Mass of CH₄ ÷ Molar mass of CH₄

Number of moles of CH₄ = 64 g ÷ 16.05 g/mol

Number of moles of CH₎ = 3.9875 mol

When rounded to the nearest whole number, the number of moles of methane in 64 grams is approximately 4.

Answer:

Pascals

Explanation:

Pascals are the unit for pressure

Answer:  Pascal

Explanation:  Pascal(Pa) is the unit of pressure according to Internataional Standard of units.

One Pascal is equivalent to the one newton(N) of force applied over an area of 1 metre squared(m2).

Thus when we are conducting an experiment on how increasing pressure during a deep sea dive affects gases in the blood, then Pascal is the most appropiate unit of measurement.

Answer:

Water supply

Explanation:

When there is drought, which happens mostly within the tropics, water sources go dry. Plants and animals suffer alike. Animals have to scramble for the limited amount of water to quench their thirsts. Water is one of the basic requirements for the survival of living organisms like animals.

Answer:

water supply

Explanation:

Answer:

A well tested explanation of a natural phenomenon

Explanation:

A scientific theory is an explanation of a natural phenomenon which has been drawn from a well tested observation.

Theories are products of repeated scientific experiments. When a hypothesis otherwise known as a "scientific guess" survives a lot of scrutiny, we can elevate it to the status of a theory. Most theories starts off from simple observations. These observations can further spark series of experiments in such a field and a scientific guess proposed. Further testing and experimenting would now lead to a theory.