Question 9 of 20
Which of the following is an example of a chemical change?
O A. A solid dissolving in a liquid
B. A solid reacting with a gas to form a new solid
C. A mixture of a solid and a liquid famming
O D. A liquid evaporating into a gas

Avogadro's number is used to determine the small entity like the atoms and the molecules. 5.5 moles of magnesium hydroxide contain 3.31 × 10²⁴ molecules.

Molecules are the small entity that makes up the compound. It is made up of similar or different atoms.

If 1 mole of magnesium hydroxide = 6.02 ×10²³ molecules

Then 5.5 moles = 33.11 × 10²³ molecules.

Therefore, 3.31 × 10²⁴ molecules of magnesium hydroxide are present in 5.5 moles.

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O=O is not a compound.

A compound consist of two different molecule at least.

Here same atom of oxygen is present in the molecule.

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d.2.93m.CaCl2 is present in the solution with a 2.93m concentration.

The boiling point of a solution is directly related to its concentration. The boiling point elevation of a solution, ΔTb, is equal to the product of the van't Hoff factor (i) and the molality of the solution (m).The quantity of moles of solute per kilogramme of solvent is known as molality.

Therefore, we can solve for the molality of the solution using the following equation:

ΔTb

\(= i *m\\105.3\°C= i * m\\\)

\(m =\frac{ 105.3 \°C }{i}\)

Assuming an ideal van't Hoff factor for CaCl2 (i = 2), the molality of the solution is:

\(m =\frac{ 105.3 \°C }{ 2}\\m = 52.65 m = 52.65 mol/kg\)

The concentration of CaCl2 in the solution is then:

\(C = m * Kb\\C = 52.65 mol/kg * 0.512 \°C/m\\C = 2.93 mol/kg\)

Therefore,The concentration of CaCl2 in the solution is  2.93m.

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complete question:The boiling point at 1.00 atm of an aqueous solution of CaCl2 is 105.3 °C. What is the concentration of CaCl2 in the solution? Kb (H2O) = 0.512 °C/m. Assume an ideal van't Hoff factor for CaCl2.

a.3.45m

b.4.40m

c.8.79m

d.2.93m

Answer: 47.2 g of sodium azide

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number \(6.023\times 10^{23}\) of particles.

To calculate the moles, we use the equation:

\(\text{Number of moles of nitrogen}=\frac{\text{Given volume}}{\text {Molar volume}}=\frac{24.4L}{22.4L}=1.09moles\)

The balanced chemical reaction is:

\(2NaN_3\rightarrow 2Na+3N_2\)  

According to stoichiometry :  

3 moles of \(N_2\) are produced by = 2 moles of \(NaN_3\)

Thus 1.09 moles of \(N_2\) are produced by =\(\frac{2}{3}\times 1.09=0.73moles\)  of \(NaN_3\)

Mass of \(NaN_3=moles\times {\text {Molar mass}}=0.73moles\times 65g/mol=47.2g\)

Thus 47.2 g of sodium azide are required to produce 24.4 L of nitrogen gas at standard temperature and pressure

An acid is a particle or substance with a pH worth of under 7.0 when present in a watery arrangement. A base (alkaline) is a particle or substance with a pH esteem higher than 7.0 when ongoing in an aqueous arrangement. Bases are the specific synthetic inverse of acids, in science.

According to Arrhenius' concept, a corrosive hoists the convergence of Hydrogen particles when disintegrated in water. According to Arrhenius' concept, a base is a compound that builds the centralization of hydroxide particles (OH- ) when deteriorating in water. In the Bronsted-Lowry Idea, acids are substances that give protons. Bases, then again, are substances that acknowledge protons. Particles that acknowledge the sets of electrons (electron pair acceptor - an electrophile), and have empty orbitals are named 'Lewis corrosive'. Particles that give a couple of electrons (electron-pair contributor - a nucleophile), and have a solitary set of electrons are named 'Lewis base'.

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Answer:

32.2 g of Na will produce 43.4 g of Na2O.

Explanation:

The balanced chemical equation for the reaction between sodium and oxygen shows that 4 moles of sodium react with 1 mole of oxygen to produce 2 moles of sodium oxide:

4Na(s) + O2(g) → 2Na2O(s)

To solve this problem, we can use the following steps:

Step 1: Convert the mass of Na given in the problem to moles using the molar mass of Na.

molar mass of Na = 23 g/mol

moles of Na = mass of Na / molar mass of Na

moles of Na = 32.2 g / 23 g/mol

moles of Na = 1.4 mol

Step 2: Use the mole ratio from the balanced chemical equation to determine the moles of Na2O produced.

From the balanced chemical equation, we can see that 4 moles of Na react to produce 2 moles of Na2O.

moles of Na2O = (moles of Na / 4) x 2

moles of Na2O = (1.4 mol / 4) x 2

moles of Na2O = 0.7 mol

Step 3: Convert the moles of Na2O to grams using the molar mass of Na2O.

molar mass of Na2O = 62 g/mol

mass of Na2O = moles of Na2O x molar mass of Na2O

mass of Na2O = 0.7 mol x 62 g/mol

mass of Na2O = 43.4 g

Therefore, 32.2 g of Na will produce 43.4 g of Na2O.

The net force on the man is 10 newtons forward. The parachute is pushing the man forward with 10 newtons of force. Therefore, option A is correct.

The vector sum of the forces exerted on a particle or object is known as the net force. The original forces' impact on the motion of the particle is replaced by the net force, which is a single force.

In accordance with Newton's second rule of motion, it causes the particle to accelerate at a rate equal to the sum of all those actual forces.

The vector sum of all forces exerted on an object is known as the net force. The net force acting on an object is zero when it is in equilibrium, whether it is at rest or moving at a constant speed. Only when all of a vector's components are zero can a vector have a magnitude of zero.

Thus, option A is correct.

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Answer: A

Explanation:

Answer:

The concentration is 2.277

Explanation:

The formula for finding the concentration of a solution is C= mole of solute divided by the volume of the solution

Therefore, C= 2.05/0.900

C=2.277

The mass of water will be produced from 150 grams of iron (III) oxide is equal to 50.7 g.

A chemical equation depicts a chemical reaction in terms of symbols of the substances. A chemical equation consists of reactants participating, products, and their physical states.

The law of conservation of mass should be followed by a balancing of a chemical equation so that the number of atoms of substances is equal on either side of the equation is a balanced chemical equation.

Given the balanced chemical equation of the reaction of iron oxide and hydrogen:

\(Fe_2O_3 + 3H_2 \longrightarrow 2Fe + 3H_2O\)

Given, the mass of the iron oxide = 150 g

The number of moles of iron oxide = 159.69 g/mol

The number of moles of iron (III) oxide = 150/159.69 = 0.939 mol

One mole of iron (III) oxide produces water = 3 mol

Then 0.939 mol of iron (III) oxide produces water = 3 ×0.939 = 2.82 mol

The mass of water produced = 2.82 ×18 = 50.7 g

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Answer:

14.9 mol

Explanation:

To find the number of moles in a given mass of a sample of sodium chloride (NaCl), we can multiply the number of grams in the sample by the molar mass of sodium chloride, which is 58.44 g/mol.

871 g × (1 mol / 58.44 g)

= 871/58.44 mol

≈ 14.9 mol

Note that we rounded to 3 significant figures in the final answer because that is how many significant figures were given in the mass measurement of the sodium chloride sample.

Answer:

C

Explanation:

I think it is C

Answer:

Geosphere and Hydrosphere.

Explanation:

Hot springs are heated by geothermal heat—heat from the Earth's interior. In volcanic areas, water may come into contact with very hot rock heated by magma. The geosphere and hydrosphere interact when hot springs form. The geosphere gets a little melted by the hot hydrosphere and then when the springs shoot up in the air they break some rocks.

Answer:

6.) 3, 12, 1, and 4   8.) 4, 1, and 3

Explanation:

By multiplying subscripts inside and outside of the parentheses you can count the number of atoms that are present. I recently answered a question for you and I did the math wrong I am going to go back and comment so you know which one and I will correct my errors. Sorry for the inconvenience!

the number of atoms in number 6:

N: 3

H: 12

P: 1

O: 4

the number of atoms for number 8:

Ca: 4

C: 1

O: 3

hope I clarified my mistake and helped you! :)

Answer:

For completely converting 6.34 moles of hydrogen to ammonia, 2.11 moles of Nitrogen is required.

The chemical reaction for the formation of ammonia by nitrogen and hydrogen reaction has been as follows:

For the formation of 2 moles of ammonia, 3 moles of hydrogen, and 1 mole of nitrogen s required.

The utilization of 3 moles of hydrogen requires 1 mole of Nitrogen.

So, the utilization of 6.34 moles of hydrogen requires:

3 moles Hydrogen = 1 -mole Nitrogen

6.34 moles hydrogen =  moles of Nitrogen

6.34 moles of hydrogen requires = 2.11 moles of Nitrogen.

For completely converting 6.34 moles of hydrogen to ammonia, 2.11 moles of Nitrogen is required.

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rating answer section

Answer rating5.0

(20 votes)

Answer:   6.77*1022 Molecules

Explanation: :)

Statement C is not true. A combination reaction is not called retrosynthesis.

Retrosynthesis is a term used in organic chemistry to describe the process of planning the synthesis of a complex molecule by breaking it down into simpler precursor compounds. On the other hand, a combination reaction refers to a chemical reaction where two or more substances combine to form a single compound.

Examples of combination reactions include the reactions mentioned in statements A and D, where magnesium reacts with oxygen to form magnesium oxide and sodium reacts with chlorine to form sodium chloride, respectively.

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Answer:

3. d

4. c

5. i

6. h

7. a

8. g

9. j

10. b

11. e

12. f

Explanation:

Answer:

Insulators

Explanation:

They could work as Insulators

Hope it Helps

Answer:

Add 2 to Cu in first part of problem only

According to the description of an ionic bond, the last choice is the right response: Ca and Br are the two components that will combine to form an ionic connection. Bromine gets electrons quickly whereas calcium loses them easily.

Between metallic and non-metallic atoms, an ionic bond is created in which all of the electrons from one atom are transferred to the other. One atom loses electrons and another receives them during this process, resulting in the formation of ions.

In general, nonmetals are willing to take electrons to form anions while metal elements are willing to donate them to make cations.

On the other hand, the octet rule describes an attribute of atoms that they require eight electrons to complete their final energy level in order to ensure stability. The noble gases that have served as the foundation for this rule.

In order to adhere to the octet rule and ensure that the elements are stable, electrons are transferred in the ionic connection in this manner.

Ca and Br are the two elements that will combine to form an ionic connection because Ca is a metal and will give electrons while Br is a non-metal and will accept them.

The final option, Ca and Br, is the pair of elements that will form an ionic bond, making it the correct response. Bromine gets electrons quickly whereas calcium loses them easily.

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Answer:

The balanced equation for this reaction is C2H2 + 502 + 4H2O + 3C02. What volume of carbon dioxide is produced when 2.8 L of oxygen are consumed? 25Explanation:

Answer:

D.

Explanation:

The volume of copper (II) sulfate in a container is equivalent to 0.650L.

Volume is the three-dimensional measure of space that comprises a length, a width and a height. It is measured in units of cubic centimeters (cm³) in metric, cubic inches or cubic feet in English measurement.

According to this question, a container seems to have about 650 mL of copper(II) sulfate solution in volume. The volume can be converted to litres as follows:

1 millilitre = 0.001 litre

650 millilitres = 0.650 litres

Therefore, 0.650L is the volume of copper II sulfate in litres.

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20.0 g of MgO will produce 28.9 g of Mg(OH)2.

The balanced equation for the reaction between MgO and H2O is:

MgO(s) + H2O(l) → Mg(OH)2(s)

The molar mass of MgO is 40.31 g/mol, and its mass is given as 20.0 g. To find the number of moles of MgO, we can divide the mass by the molar mass:

n(MgO) = 20.0 g / 40.31 g/mol = 0.496 mol

The stoichiometry of the reaction shows that one mole of MgO reacts to form one mole of Mg(OH)2. Hence, the number of moles of Mg(OH)2 produced will be the same as the number of moles of MgO reacted:

n(Mg(OH)2) = n(MgO) = 0.496 mol

The molar mass of Mg(OH)2 is 58.32 g/mol

The mass of Mg(OH)2 produced=

m(Mg(OH)2) = n(Mg(OH)2) × M(Mg(OH)2) = 0.496 mol × 58.32 g/mol = 28.9 g

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At equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

1: Write the balanced chemical equation:

\(C_O\)(g) + \(Cl_2\)(g) ⟶ \(C_OCl_2\)(g)

2: Set up an ICE table to track the changes in moles of the substances involved in the reaction.

Initial:

\(C_O\)(g) = 0.3500 mol

\(Cl_2\)(g) = 0.05500 mol

\(C_OCl_2\)(g) = 0 mol

Change:

\(C_O\)(g) = -x

\(Cl_2\)(g) = -x

\(C_OCl_2\)(g) = +x

Equilibrium:

\(C_O\)(g) = 0.3500 - x mol

\(Cl_2\)(g) = 0.05500 - x mol

\(C_OCl_2\)(g) = x mol

3: Write the expression for the equilibrium constant (Kc) using the concentrations of the species involved:

Kc = [\(C_OCl_2\)(g)] / [\(C_O\)(g)] * [\(Cl_2\)(g)]

4: Substitute the given equilibrium constant (Kc) value into the expression:

1.2 x \(10^3\) = x / (0.3500 - x) * (0.05500 - x)

5: Solve the equation for x. Rearrange the equation to obtain a quadratic equation:

1.2 x \(10^3\) * (0.3500 - x) * (0.05500 - x) = x

6: Simplify and solve the quadratic equation. This can be done by multiplying out the terms, rearranging the equation to standard quadratic form, and then using the quadratic formula.

7: After solving the quadratic equation, you will find two possible values for x. However, since the number of moles cannot be negative, we discard the negative solution.

8: The positive value of x represents the number of moles of \(Cl_2\)(g) at equilibrium. Substitute the value of x into the expression for \(Cl_2\)(g):

\(Cl_2\)(g) = 0.05500 - x

9: Calculate the value of \(Cl_2\)(g) at equilibrium:

\(Cl_2\)(g) = 0.05500 - x

\(Cl_2\)(g) = 0.05500 - (positive value of x)

10: Calculate the final value of \(Cl_2\) (g) at equilibrium to get the answer.

Therefore, at equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

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The values of X and Y in the diagram represent the progress of the reaction along the x-axis and the potential energy along the y-axis, respectively.

To determine whether the student's sketch of the potential energy diagram for an exothermic reaction is correct or incorrect, we need to understand the characteristics of such a reaction. In an exothermic reaction, the reactants have a higher energy level than the products, and energy is released during the reaction.The potential energy diagram should have the reactants positioned at a higher energy level (y-axis) than the products. As the reaction progresses from reactants to products, the potential energy should decrease, indicating the release of energy. This decrease in energy should be evident in the form of a downward slope or a curve.If the student's sketch accurately depicts these characteristics, with the reactants at a higher energy level than the products and a downward slope or curve indicating energy release, then the diagram is correct. However, if the student's sketch shows the reactants at a lower energy level or depicts an upward slope, it would be incorrect.The x-axis typically represents the reaction coordinate, which can be the extent of the reaction or the progression of time.

The y-axis represents the potential energy, which can be measured in joules or any other energy unit. The specific values on the axes will depend on the reaction and the units chosen.

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Answer:

6.67* 1011 Hz

Explanation:

a p e x

Answer:

Awnser above is correct

Explanation:

a. 6.67