What is a physical change and a chemical change

Answer:

liquid takes the shape of whatever container it is in and have a volume but gas doesn't have a volume

Answer:

liquid because you can take the volume of water and the shape depends on the container

Answer:

a. the water represents -- 3.the ocean

b. the sides of the tank represent   -- 4.continents

c. blowing through the straw represents  ---  2.prevailing winds

d. the moving pepper helps illustrate the movement of  --  1. currents

Explanation:

Answer: The mass of product, \(H_2O\) is, 36.0 grams.

Explanation : Given,

Mass of \(H_2\) = 4.0 g

Mass of \(O_2\) = 32.0 g

Molar mass of \(H_2\) = 2 g/mol

Molar mass of \(O_2\) = 32 g/mol

First we have to calculate the moles of \(H_2\) and \(O_2\).

\(\text{Moles of }H_2=\frac{\text{Given mass }H_2}{\text{Molar mass }H_2}\)

\(\text{Moles of }H_2=\frac{4.0g}{2g/mol}=2.0mol\)

and,

\(\text{Moles of }O_2=\frac{\text{Given mass }O_2}{\text{Molar mass }O_2}\)

\(\text{Moles of }O_2=\frac{32.0g}{32g/mol}=1.0mol\)

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation is:

\(2H_2+O_2\rightarrow 2H_2O\)

From the balanced reaction we conclude that

2 mole of \(H_2\) react with 1 mole of \(O_2\)

From this we conclude that, there is no limiting and excess reagent.

Now we have to calculate the moles of \(H_2O\)

From the reaction, we conclude that

2 moles of \(H_2\) react to give 2 moles of \(H_2O\)

Now we have to calculate the mass of \(H_2O\)

\(\text{ Mass of }H_2O=\text{ Moles of }H_2O\times \text{ Molar mass of }H_2O\)

Molar mass of \(H_2O\) = 18 g/mole

\(\text{ Mass of }H_2O=(2.0moles)\times (18g/mole)=36.0g\)

Therefore, the mass of product, \(H_2O\) is, 36.0 grams.

Answer:

Double Covalent

Explanation:

When two of the same element combine it will always be a covalent bond between them and since sulfur has two lone electrons it will make a double bond between the two to have a full octect

Answer:

nucleosynthesis

Explanation:

The correct answer is nucleosynthesis.

After the hydrogen in the star's core is exhausted, the star can fuse helium to form progressively heavier elements, carbon and oxygen, and so on, until iron and nickel are formed. Up to this point, the fusion process releases energy. The formation of elements heavier than iron and nickel requires an input of energy.

In a supernova explosion, neutron capture reactions take place (this is not fusion), leading to the formation of heavy elements. This is the reason why it is said that most of the stuff that we see around us comes from stars and supernovae (the heavy elements part).

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The percent by mass of nitrogen in ammonia (NH3) is approximately 82.15%

Calculating the mass of nitrogen to the total mass of the compound and then expressing the result as a percentage will allow us to determine the percent by mass of nitrogen in NH3 (ammonia).

Ammonia's molecular structure, NH3, indicates that it is made up of one nitrogen atom (N) and three hydrogen atoms (H). We must take both the molar masses of nitrogen and ammonia into account when calculating the percent by mass of nitrogen.

Nitrogen's (N) molar mass is roughly 14.01 g/mol. The molar masses of nitrogen and hydrogen are added to determine the molar mass of ammonia (NH3). Since hydrogen's molar mass is around 1.01 g/mol, ammonia's molar mass is:

(3 mol H 1.01 g/mol) + (1 mol N 14.01 g/mol) = 17.03 g/mol = NH3.

Now, we can use the following formula to get the nitrogen content of ammonia in percent by mass:

(Mass of nitrogen / Mass of ammonia) / 100% is the percentage of nitrogen by mass.

Ammonia weighs 17.03 g/mol and contains 14.01 g/mol of nitrogen by mass. By entering these values, we obtain:

(14.01 g/mol / 17.03 g/mol) 100% 82.15 % of nitrogen by mass

Ammonia (NH3) has a nitrogen content that is roughly 82.15 percent by mass.

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1) Balance the chemical equation.

2) List the elements in the reactant and in the products.

Reactants:

C: 1

H: 4

O: 3

Products:

C: 1

H: 2

O: 3

BalanceH.

Reactants:

C: 1

H: 4

O: 3

Products:

C: 1

H: 4

O: 4

Balance oxygen

Multiply every coefficient by the denominator

Reactants:

C: 2

H: 8

O: 8

Products:

C: 2

H: 8

O: 8

3) Moles of CH3OH needed to produce 3 mol CO2.

The molar ratio between CH3OH and CO2 is 2 mol CH3OH: 2 mol CO2.

The moles of CH3OH needed are 3 mol.

.

Answer:

7.94x10⁻⁸ M

Explanation:

Using the pH given by the problem, we can calculate the pOH of the blood plasma:

Then we can proceed to calculate the [OH⁻] of the blood plasma, using the definition of pOH:

Answer:

An element is a pure substance.

An element is made of only one type of atom.

An element cannot be broken down into a simpler form.

Explanation:

The sample containing 1.00 mg of iodine-129 would have an activity of 1900 disintegrations per second.

The first step in solving this problem is to determine the number of iodine-129 atoms present in 1.00 mg of the sample. We can use the Avogadro's number (6.022 × 10^23 atoms per mole) and the molar mass of iodine-129 (129 g/mol) to calculate this:

Number of iodine-129 atoms = (1.00 mg / 129 g/mol) x (6.022 × 10^23 atoms/mol)

= 4.66 × 10^16 atoms

Next, we can use the half-life of iodine-129 (1.7 × 10^7 years) to calculate the decay constant (λ) using the following equation:

λ = ln(2) / half-life

λ = ln(2) / 1.7 × 10^7 years

= 4.09 × 10^-8 per year

Now, we can use the decay constant and the number of iodine-129 atoms to calculate the activity (A) in disintegrations per second (Bq):

A = λ x N

A = (4.09 × 10^-8 per year) x (4.66 × 10^16 atoms)

= 1900 Bq

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The mass of the asteroid is C. 1.2 x \(10^{12}\) Kg

To find the mass of the other asteroid, we can rearrange the equation for the gravitational force between two objects:

F = (G * m1 * m2) / \(r^{2}\)

where F is the force of gravity, G is the gravitational constant, m1 and m2 are the masses of the two asteroids, and r is the distance between them.

Given that the distance between the asteroids is 75000 m, the force of gravity between them is 1.14 N, and one asteroid has a mass of 8 x \(10^{7}\) kg, we can substitute these values into the equation and solve for the mass of the other asteroid (m2):

1.14 N = (6.67430 × \(10^{-11}\) N \(m^{2}\)/\(Kg^{2}\) * 8 x \(10^{7}\) kg * \(m2\)) / \((75000 m)^{2}\)

Simplifying and solving the equation, we find that the mass of the other asteroid (m2) is approximately 1.2 x \(10^{12}\) kg. Therefore, Option C is correct.

The question was incomplete. find the full content below:

Two asteroids are 75000 m apart one has a mass of 8 x \(10^{7}\) kg if the force of gravity between them is 1.14 what is the mass of the asteroid

A. 3.4 x \(10^{11}\) kg

B. 8.3 x \(10^{12}\) kg

C. 1.2 x \(10^{12}\) kg

D. 1.2 x \(10^{10}\) kg

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Answer: pressure exerted by vapor

Explanation:

Quartz is not regarded as an example of a modified silicate.

This is defined as a hard, crystalline mineral composed of silica with a tetrahedral shape. Silica is also referred to as Silicon dioxide(SiO₂).

This type of mineral is a naturally occurring crystal and isn't a modified silicate but the rest can be modified using their respective constituents thereby making option D the most appropriate choice.

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We're given the [OH⁻] as 8.34 × 10⁻¹² M. Using the formula pOH = -log[OH⁻], the pOH of this solution would be -log(8.34 × 10⁻¹²) ≈ 11.08.

The pOH is, for lack of a better term, the "opposite" of pH: A pOH of 7 is neutral; a pOH less than 7 is basic; and a pOH greater than 7 is acidic.

This follows from the relation, pH + pOH = 14. In this case, with a pOH of 11.08, our pH would be 14 - 11.08 = 2.92, which is acidic (pH < 7).

Thus, the correct answer choice is B.

The gas is confined in 3.0 L container ( rigid container) ⇒ the volume remains constant when the temperature is increased from from 27oC to 77oC and therefore V1=V2 .

Ideal gas law is valid only for ideal gas not for vanderwaal gas. Ideal gas is a hypothetical gas. Vanderwaal gas can behave as ideal gas at low pressure and high temperature. Therefore the final pressure is 1,750 mmHg.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature.

Mathematically the relation between Pressure, volume and temperature can be given as

PV=nRT

where,

P = pressure of gas

V= volume of gas

n =number of moles of gas

T =temperature of gas

R = Gas constant = 0.0821 L.atm/K.mol

At constant volume, the above equation can be rearranged as

P₁/T₁ = P₂/T₂

Substituting all the given values in the above equation, we get

1500 ÷300= P₂÷350

P₂ =1,750 mmHg

Therefore the final pressure is 1,750 mmHg.

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The amount of heat energy produced when 1 g of hydrogen and 2 g of nitrogen are reacted, is -6.61 KJ

First, we shall obtain the limiting reactant. Details below:

3H₂ + N₂ -> 2NH₃

From the balanced equation above,

28 g of N₂ reacted with 6 g of H₂

Therefore,

2 g of N₂ will react with = (2 × 6) / 28 = 0.43 g of H₂

We can see that only 0.43 g of H₂ is needed in the reaction.

Thus, the limiting reactant is N₂

Finally, we the amount of heat energy produced. Details below:

3H₂ + N₂ -> 2NH₃ ΔH = -92.6 KJ

From the balanced equation above,

When 28 grams of N₂ reacted, -92.6 KJ of heat energy were produced.

Therefore,

When 2 grams of N₂ will react to produce = (2 × -92.6) / 28 = -6.61 KJ

Thus the heat energy produced from the reaction is -6.61 KJ

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Answer:

carbon atom is used to determine the amt of particles in a mole

Answer:

6.76 mol/L

Explanation:

A chemist prepares a solution 0.607 kg of calcium bromide by measuring out of calcium bromide into a 450. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's calcium bromide solution. Be sure your answer has the correct number of significant digits.

Step 1: Given data

Step 2: Calculate the moles of solute

The molar mass of calcium bromide is 199.89 g/mol.

607 g × 1 mol/199.89 g = 3.04 mol

Step 3: Convert "V" to liters

We will use the conversion factor 1 L = 1000 mL.

450. mL × 1 L/1000 mL = 0.450 L

Step 4: Calculate the concentration of calcium bromide in mol/L

[CaBr₂] = 3.04 mol/0.450 L = 6.76 mol/L

Answer:

Normality is the number of gram equivalents of solute divided by the volume in liters.

The molarity is the amount of moles in solute divided by the volume in liters.

Moles are the molar mass times grams if you're curious

I hope this helps and good luck!

Answer:

Molarity and normality describe the numbers (moles) of reactants or products dissolved in one liter of solution. Molarity: M = moles of solute contained in one liter of solution. ... Normality is always a multiple of molarity. It describes the “equivalent” moles of reactants involved in chemical reactions.

Explanation:

Normality is a measure of concentration equal to the gram equivalent weight per litre of solution. Gram equivalent weight is the measure of the reactive capacity of a molecule. The solute's role in the reaction determines the solution's normality. Normality is also known as the equivalent concentration of a solution.

Molar concentration is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution.

Formula for Molar: M = \(\frac{n}{v}\)

The molecules in a copper penny is closely packed and and has no space to move apart thus the material will be denser than that in the molten state. That's why the penny sink in the molten copper.

Copper is a transition metal exhibiting all the metallic properties. The molten state of metals is the fluid state where the molecule are not strongly held by the metallic bonds.

Molten material is made by melting them and the liquid like state contains molecules with some space to move apart. Whereas, in solid state as in a copper penny, the molecules are closely packed and have no space to move apart.

An object will sink in a liquid if it is less dense than the liquid. Copper penny is denser than the molten copper because the molecules are densely packed and it will sink on to it.

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Okay I will explain you friend...

To get pure alumina, you should follow these below steps.

Step (1):- Impurity alumina is treated with conc. NaOH solution to form sodium aluminate.

\({ \green{ \tt{Al2O3 + 2NaOH + 3H2O → 2Na[Al(OH)4]}}}\)

Step (2):- sodium aluminate is treated with carbon dioxide gas to form precipitated Al2O3

\({ \purple{ \tt{2Na[Al(OH)4] + CO2 → Al2O3.xH2O + NaHCO3}}}\)

Step (3):- Precipitated Al2O3 separated by filtration and heated at 1470K to give pure alumina.

\({ \blue{ \tt{Al2O3.xH2O \: \: —(1470K)→ Al2O3 + xH2O}}}\)

Answer:

H2SO4 + 2KOH → K2SO4 + 2H2O

Explanation:

In a neutralization reaction between an acid and a base, the positive ion from the base and the negative ion from the acid usually form a salt. In this case, the positive potassium ion (K+) bonds with the polyatomic sulfate ( S O 2 4 ) to form the salt K 2 S O 4.

The water H O H or H 2 O is formed by the positive hydrogen (H + ) ion from the acid and the negative hydroxide ion (OH) from the base.

Answer:

\( \huge 3.986 \times { 10}^{ - 5} \: \: mol \\ \)

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

\(n = \frac{N}{L} \\\)

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

\(n = \frac{24 \times {10}^{18} }{6.02 \times {10}^{23} } \\ \\ = 3.986 \times { 10}^{ - 5} \: \: mol\)

Hope this helps you

The balanced equation obeys the law of conservation of mass because the number of atoms of each element (carbon, hydrogen, and oxygen) is the same on both sides of the equation.

To balance the equation CH4 + O2 → CO2 + H2O, we need to ensure that the number of atoms of each element is the same on both sides of the equation.

Starting with carbon (C), there is one carbon atom on the left side (CH4) and one carbon atom on the right side (CO2). Carbon is already balanced.

Moving on to hydrogen (H), there are four hydrogen atoms on the left side (CH4) and two hydrogen atoms on the right side (H2O). To balance hydrogen, we can add a coefficient of 2 in front of H2O:

CH4 + O2 → CO2 + 2H2O

Now, let's consider oxygen (O). There are two oxygen atoms on the left side (O2) and two oxygen atoms on the right side (CO2 + 2H2O). Oxygen is already balanced.

The balanced equation is:

CH4 + O2 → CO2 + 2H2O

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Molecules with polar bonds or specific functional groups with asymmetric vibrations are most strongly affected by infrared photons. Molecules with nonpolar bonds or symmetric functional groups that lack infrared-active vibrations are least affected.

When a photon interacts with a molecule, the degree to which the molecule is affected depends on whether the photon's energy matches the energy required to excite the molecule's vibrational modes. Infrared (IR) photons have energies that correspond to molecular vibrations, and therefore, molecules with certain characteristics are most strongly affected by them. Molecules with polar bonds or functional groups containing asymmetric stretching or bending vibrations are most strongly affected by infrared photons. Examples include water (H2O), carbon dioxide (CO2), ammonia (NH3), and various organic compounds with functional groups like carbonyl (C=O) and hydroxyl (OH). Molecules with nonpolar bonds or symmetric functional groups that lack vibrational modes in the infrared region are least affected by infrared photons. These include diatomic molecules like oxygen (O2), nitrogen (N2), and noble gases such as helium (He). Hence Molecules with polar bonds or specific functional groups with asymmetric vibrations are most strongly affected by infrared photons. Molecules with nonpolar bonds or symmetric functional groups that lack infrared-active vibrations are least affected.

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Answer: It is indeed A.Standard Solution.

Hope this helps you!

Answer:  a) \(2H_2(g)+O_2(g)\rightarrow 2H_2O(g)\)

b) 4.00 L of \(H_2O\) will be produced

Explanation:

a) The balanced chemical reaction is:

\(2H_2(g)+O_2(g)\rightarrow 2H_2O(g)\)

b) According to avogadros law, equal moles of gases occupy equal volumes at same temperature and presure conditions.

According to stoichiometry :

2 L of \(H_2\) require  = 1 L of \(O_2\)

Thus 4.00 L of \(H_2\) will require=\(\frac{1}{2}\times 4.00=2.00L\)  of \(O_2\)

Thus \(H_2\) is the limiting reagent as it limits the formation of product and \(O_2\) is the excess reagent.

As 2 L of \(H_2\) give = 2 L of \(H_2O\)

Thus 4.00 L of \(H_2\) give =\(\frac{2}{2}\times 4.00=4.00L\)  of \(H_2O\)

Thus 4.00 L of \(H_2O\) will be produced

a. The balanced reaction for the process should be 2h_2(g) + O_2(g) ⇒2H_2O(g)

b. The number of liters of water vapor should be 4.00 liters of H_2O.

a. The balanced reaction for the process should be 2h_2(g) + O_2(g) ⇒2H_2O(g)

b. As per the law, the equal moles of gases occupied equal volumes at the similar temperature

So, the number of liters should be

= 2/2*4.00

= 4.00 of H_2O

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Answer:

7.5 atm

Explanation:

Initial pressure P1 = 1.0 ATM

Initial volume V1= 196 L

Final pressure P2= the unknown

Final volume V2= 26000ml or 26 L

From Boyle's law we have;

P1V1= P2V2

P2= P1V1/V2

P2= 1.0 × 196/26

P2 = 7.5 atm

Therefore, as the air is compressed, the pressure increases to 7.5 atm.

Answer: 0.734 moles of CH4 will produce 114.50 grams of Al(OH)3

Explanation: To determine the number of grams of Al(OH)3 produced from 0.734 moles of CH4, we need to use the balanced chemical equation that relates the two compounds, and then use stoichiometry to convert from moles of CH4 to moles of Al(OH)3 and finally to grams of Al(OH)3.

The balanced chemical equation for the reaction between CH4 and Al(OH)3 is:

CH4 + 4Al(OH)3 → 2Al(OH)3 + CH4O

From the equation, we can see that for every 1 mole of CH4, 2 moles of Al(OH)3 are produced.

So, starting with 0.734 moles of CH4, we can calculate the number of moles of Al(OH)3 produced:

Moles of Al(OH)3 = 0.734 moles CH4 x (2 moles Al(OH)3 / 1 mole CH4)

= 1.468 moles Al(OH)3

Now that we know the number of moles of Al(OH)3 produced, we can calculate the mass of Al(OH)3 using its molar mass:

Molar mass of Al(OH)3 = (1 x atomic weight of Al) + (3 x atomic weight of O) + (3 x atomic weight of H)

= (1 x 26.98 g/mol) + (3 x 16.00 g/mol) + (3 x 1.01 g/mol)

= 78.00 g/mol

Mass of Al(OH)3 = Moles of Al(OH)3 x Molar mass of Al(OH)3

= 1.468 moles x 78.00 g/mol

= 114.50 g

Therefore, 0.734 moles of CH4 will produce 114.50 grams of Al(OH)3.