In science, what is it called when you have a statement that can be mathematically modeled, based
on repeated experimental observations, that describes some phenomenon of nature?

The statement which best describes a pure substance is that it has constant physical properties which is therefore denoted as option B.

This is referred to as a single kind of matter that cannot be separated into other kinds of matter by any physical means.

This type of sample of matter has both definite and constant composition and distinct chemical properties and is referred to as being homogeneous in nature with no form of impurities which is therefore the reason why it was chosen a the correct choice.

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Answer:

Therefore, approximately 8.5 mL of chlorine gas can be produced from the decomposition of 25 g of aluminum chloride at 28°C and 750 mmHg.

Explanation:

The decomposition of aluminum chloride will not produce oxygen. Instead, it produces aluminum oxide and chlorine gas. The balanced chemical equation for this reaction is:

2AlCl3(s) → Al2O3(s) + 3Cl2(g)

To determine the volume of chlorine gas produced from the decomposition of 25 g of aluminum chloride, we need to use the ideal gas law, which is PV = nRT, where P is the pressure of the gas in atmospheres, V is the volume of the gas in liters, n is the number of moles of gas, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is the temperature of the gas in Kelvin.

First, we need to determine the number of moles of aluminum chloride. The molar mass of AlCl3 is 133.34 g/mol, so:

25 g AlCl3 × (1 mol AlCl3/133.34 g AlCl3) = 0.187 moles AlCl3

According to the balanced chemical equation, 2 moles of AlCl3 will produce 3 moles of Cl2 gas. Therefore, 0.187 moles of AlCl3 will produce:

0.187 moles AlCl3 × (3 moles Cl2/2 moles AlCl3) = 0.2805 moles Cl2

Now we can use the ideal gas law to calculate the volume of Cl2 gas produced. We need to convert the temperature from Celsius to Kelvin by adding 273.15.

PV = nRT

V = nRT/P

V = (0.2805 mol) × (0.0821 L·atm/mol·K) × (301.15 K) / (750 mmHg × 1 atm/760 mmHg)

V = 0.0085 L or 8.5 mL (rounded to two significant figures)

Therefore, approximately 8.5 mL of chlorine gas can be produced from the decomposition of 25 g of aluminum chloride at 28°C and 750 mmHg.

The mass of Fe2S3 formed would be 12.0 g

The limiting reactant is iron (Fe)

The percent yield of iron (III) sulfide would be 108.4%

Fe + S -> FeS

From the equation, we see that one mole of Fe reacts with one mole of S to produce one mole of FeS. To determine the mass of FeS that can be formed, we need to determine which reactant is limiting and which is in excess.

Number of moles of Fe = mass / molar mass = 7.62 g / 55.845 g/mol = 0.136 moles

Number of moles of S = mass / molar mass = 8.67 g / 32.06 g/mol = 0.27 moles

We see that Fe is limiting because there are fewer moles of Fe than S. The stoichiometry of the reaction tells us that one mole of Fe produces one mole of FeS.

The mass of FeS that can be formed is:

mass = number of moles × molar mass

mass = 0.136 moles × 87.91 g/mol (molar mass of FeS)

mass = 12.0 g

percent yield = actual yield / theoretical yield × 100%

percent yield = 13.01 g / 12.0 g × 100%

percent yield = 108.4%

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Courtney burns wood in an outdoor firepit and she measures mass of the ashes that remain after the fire, and mass is much lower than the wood that she burned. The best explanation for what Courtney observes is that: A. gases are released into the air.

When wood burns, it undergoes chemical reaction called combustion, where it reacts with oxygen from the air to produce carbon dioxide, water vapor and other gases. These gases are released into air as the wood burns and their mass is not accounted for in ashes left behind.

Water inside the wood may also be released as steam during combustion process but this would not explain the significant difference in mass between the wood and ashes.

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Answer:0.146 torr

Explanation:

Yes to the gas constant

you use 0.0821 L.atm/mol.k  If you want pressure in atm

use 62.44 L.torr/ mol.k  if you want pressure in torr

n=PV/RT

n= 722.4 X 3.79/(62.44 X 300) =

The final temperature of the water will be approximately 50.0°C (to two significant figures).

To solve this problem, we need to use the specific heat capacity equation:

q = m * c * ΔT

where

q is the amount of heat energy added,

m is the mass of the water,

c is the specific heat capacity of water, and

ΔT is the change in temperature.

First, we need to determine the initial temperature of the water. We are given that the water is initially at 40.0°C.

Next, we can calculate the amount of heat energy that is added to the water:

q = 418 J

m = 10.0 grams.

c is 4.184 J/g°C.

We can rearrange the equation to solve for ΔT:

ΔT = q / (m * c)

ΔT = 418 J / (10.0 g * 4.184 J/g°C) = 9.99°C

This is the change in temperature of the water. To find the final temperature, we add this to the initial temperature:

Final temperature = 40.0°C + 9.99°C = 49.99°C

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Answer: Your welcome!

Explanation:

Answer 1: Ice, water, sugar, lemon juice

Answer 2: Liquid in a gas

Answer 3: Saturated

Answer 4: Dissolution

Answer 5: Moles of solute/liters of solution

Answer 6: Strong electrolytes completely dissociate in water, weak electrolytes partially dissociate, and nonelectrolytes do not dissociate.

Answer 7: Molarity

Answer 8: Saturated

Answer 9: Freezing-point depression

Answer 10: Silver chloride (AgCl)

The elements which come after 'C' and 'Si' are 'Ge' and 'Sn'. The element 'F' is the most electronegative element. Down the group the electronegativity generally decreases.

The electronegativity of an atom is defined as the relative tendency or power of the bonded atom in a molecule to attract the shared pair of electrons towards itself.

In general the electronegativity decreases on moving down a group. The increase in the size of atoms and the shielding effect of inner electrons decreases the electronegativity.

Here 'Ge' and 'Sn' comes below 'C' and 'Si'.

Thus the electronegativity of the elements after 'C' and 'Si' decreases.

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The scientist I have chosen is J.J. Thomson, who made significant contributions to the study of atomic structure in the late 19th and early 20th centuries.

Thomson's most well-known contribution is his discovery of the electron, which he identified as a negatively charged particle present in all atoms. This discovery formed the basis of Thomson's "plum pudding" model of the atom, which proposed that atoms consisted of a positively charged "pudding" with negatively charged electrons scattered throughout.

While this model was eventually disproven, Thomson's discovery of the electron and his work on the measurement of atomic and molecular masses laid the foundation for the modern atomic model. Specifically, Thomson's work on mass spectrometry led to the development of more advanced techniques for determining the masses and properties of atoms and molecules, which are still used in modern research today.

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2.50 g of helium gas at STP would occupy a volume of 14.0 liters.

Standard temperature and pressure (STP) conditions of 0°C and 1 atm, we can use the molar volume of a gas at STP, which is 22.4 L/mol.

1. Helium seems to have a molar mass of 4.00 g/mol.

Therefore, we can calculate the number of moles of helium as:

moles of He = mass of He divided by molar mass of He

= 2.50 g / 4.00 g/mol

= 0.625 mol

Then, we can use the molar volume of a gas at STP to calculate the volume of helium gas:

volume of He = moles of He x molar volume of gas at STP

= 0.625 mol x 22.4 L/mol

= 14.0 L

2.50 g of helium gas at STP would occupy a volume of 14.0 liters.

2. The molar mass of sodium is 22.99 g/mol. Therefore, we can calculate the number of moles of sodium as:

moles of Na = number of atoms of Na divided by Avogadro's number

= 5.0 x 10²⁵ atoms / 6.022 x 10²³ atoms/mol

= 83.0 mol

Then, we can use the molar mass of sodium to calculate the mass of sodium:

mass of Na = moles of Na x molar mass of Na

= 83.0 mol x 22.99 g/mol

= 1900 g

Therefore, 5.0 x 10²⁵ atoms of sodium have a mass of 1900 g.

3. The molar mass of Ni is 58.69 g/mol. Therefore, we can calculate the number of moles of Ni as:

moles of Ni = mass of Ni divided by molar mass of Ni

= 3.95 g / 58.69 g/mol

= 0.0673 mol

Then, we can use Avogadro's number to calculate the number of atoms of Ni:

number of atoms of Ni = moles of Ni x Avogadro's number

= 0.0673 mol x 6.022 x 10²³ atoms/mol

= 4.05 x 10²² atoms

Therefore, 3.95 g of Ni contain 4.05 x 10²² atoms.

4. The molar mass of Xe is 131.29 g/mol. Therefore, we can calculate the number of moles of Xe as:

moles of Xe = mass of Xe divided by molar mass of Xe

= 15 kg / 131.29 g/mol

= 114 mol

Then, we can use Avogadro's number to calculate the number of atoms of Xe:

number of atoms of Xe = moles of Xe x Avogadro's number

= 114 mol x 6.022 x 10^23 atoms/mol

= 6.87 x10²⁵ atoms

Therefore, a 15 kg sample of Xe gas contains 6.87 x 10²⁵ atoms.

5. A gas's molar volume at STP is 22.4 L/mol. Therefore, we can calculate the number of moles of Ar as:

moles of Ar = number of atoms of Ar divided by Avogadro's number

= 45,000,000 atoms / 6.022 x 10²³ atoms/mol

= 7.47 x 10⁻¹⁷ mol

Then, we can use the molar volume of a gas at STP to calculate the volume of Ar gas:

volume of Ar = moles of Ar x molar volume of gas at STP

= 7.47 x 10⁻¹⁷ mol x 22.4 L/mol

= 1.67 x  10⁻¹⁵ L

Therefore, 45,000,000 atoms of Ar would occupy a volume of 1.67 x 10⁻¹⁵ liters at STP.

6. The molar mass of CO₂ is 44.01 g/mol. Therefore, we can calculate the number of moles of CO₂ as:

moles of CO₂ = mass of CO₂ divided by molar mass of CO₂

= 75 g / 44.01 g/mol

= 1.70 mol

Then, we can use Avogadro's number to calculate the number of atoms of CO₂:

number of atoms of CO₂ = moles of CO₂ x Avogadro's number

= 1.70 mol x 6.022 x 10²³ atoms/mol

= 1.02 x 10²⁴ atoms

Therefore, a 75 g sample of CO₂ contains 1.02 x 10²⁴ atoms.

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As per the pictorial representation,the first image is of an element while the second one is that of a mixture of an element and a compound.

It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.

Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.

The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.

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Explanation:

Mammals and birds have a unique metabolic process that allows them to generate their own body heat, known as endothermy or warm-bloodedness. This means that they can regulate their body temperature internally, regardless of the external temperature.

The process of generating heat requires a lot of energy, which is primarily produced through the breakdown of nutrients, such as glucose and fatty acids, obtained from food. The mitochondria, which are present in almost all cells of the body, play a critical role in this process. They use oxygen to convert these nutrients into energy in the form of ATP (adenosine triphosphate), which powers the metabolic processes necessary for maintaining body temperature.

Mammals and birds also have specialized tissues that help generate and conserve heat, such as brown adipose tissue and feathers. These tissues contain a high density of mitochondria, which allows for more efficient energy production and heat generation.

Overall, the ability of mammals and birds to generate their own heat is a key adaptation that enables them to thrive in a wide range of environments, from the icy poles to the scorching deserts.

Answer: .38 atm

Explanation:

p2= p1 x t2 / t1

0.45 x 259.15 / 303.15

Answer:

Explanation:

To calculate the percent yield of a reaction, we need to compare the actual yield (the amount of product obtained in the experiment) with the theoretical yield (the amount of product that should have been obtained based on stoichiometric calculations).

The balanced chemical equation for the reaction between magnesium bromide (MgBr2) and hydroiodic acid (HI) is:

MgBr2 + 2HI → MgI2 + 2HBr

From this equation, we can see that 1 mole of MgBr2 reacts with 2 moles of HI to produce 1 mole of MgI2 and 2 moles of HBr. We can use this information to calculate the theoretical yield of HBr that should have been obtained based on the amount of MgBr2 used:

Calculate the moles of MgBr2 used:

moles of MgBr2 = mass / molar mass = 24.5 g / 184.11 g/mol = 0.133 moles

Use the mole ratio from the balanced equation to calculate the moles of HBr that should have been produced:

moles of HBr = 2 x moles of MgBr2 = 2 x 0.133 moles = 0.266 moles

Calculate the mass of HBr that should have been produced:

mass of HBr = moles of HBr x molar mass = 0.266 moles x 80.91 g/mol = 21.47 g

So the theoretical yield of HBr is 21.47 g.

The actual yield of HBr obtained in the experiment is 8.23 g.

We can now calculate the percent yield as:

percent yield = (actual yield / theoretical yield) x 100%

percent yield = (8.23 g / 21.47 g) x 100%

percent yield = 38.4%

Therefore, the percent yield of the reaction is approximately 38.4%.

Answer:

In ionic bonding, atoms transfer electrons to each other. Ionic bonds require at least one electron donor and one electron acceptor. In contrast, atoms with the same electronegativity share electrons in covalent bonds, because neither atom preferentially attracts or repels the shared electrons.

They share electrons between them

The mass of hydrogen gas produced when 12 grams of zinc reacts with excess sulfuric acid is 0.370 g.

Ratio between the mass and amount of substance (measured in moles) of any sample is called molar mass.

Zn + H2SO4 -> ZnSO4 + H2

Molar mass of zinc is 65.38 g/mol.

moles of zinc is mass of zinc / molar mass of zinc

moles of zinc = 12 g / 65.38 g/mol

moles of zinc = 0.1838 mol

Moles of hydrogen gas is equal to moles of zinc

moles of hydrogen gas = 0.1838 mol

So, mass of hydrogen gas = moles of hydrogen gas x molar mass of hydrogen gas

mass of hydrogen gas = 0.1838 mol x 2.016 g/mol (molar mass of H2)

mass of hydrogen gas = 0.370 g

Therefore, the mass of hydrogen gas produced when 12 grams of zinc reacts with excess sulfuric acid is 0.370 g.

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Answer:

After millions of years underground, the compounds that make up plankton and plants turn into fossil fuels. Plankton decomposes into natural gas and oil, while plants become coal. Today, humans extract these resources through coal mining and the drilling of oil and gas wells on land and offshore.

Explanation:

Fossil fuels such as oil, coal and natural gas formed from living organisms on land and in sea are non-renewable resources created by the extinction of prehistoric plants and animals that are gradually being buried under rock layers.

Crude oil (also called crude oil or simply petroleum) is a fossil fuel formed from the remains of ancient marine organisms.  After it died and sank to the bottom of the sea, the organic material mixed with other sediments and was buried.

Over the years, the rubble has been covered by layers of sand and silt. The heat and pressure of these layers helped turn the remains into what we now call oil or petroleum (fossil fuels).

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If we decrease the temperature to 200 K at constant pressure, 13.3 L  would the new volume .

What is temperature?

Temperature is a unit used to represent how hot or cold something is. It can be stated using the Celsius or Fahrenheit scales, among others. Temperature shows which way heat energy will naturally flow, i.e., from a hotter (body with a higher temperature) to a colder (body with a lower temperature) (one at a lower temperature).

What is pressure?

As force applied per unit area, pressure is defined. P=FA, where F is the force operating perpendicular to the surface area A, gives it mathematical expression. The pascal (Pa), which equates to a newton per square metre (N/m 2), is the accepted unit of pressure.

Therefore, If we decrease the temperature to 200 K at constant pressure, 13.3 L  would the new volume .

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The compound is an acid

H2SO4, or sulfuric acid, is an acid because it donates protons (H+ ions) in aqueous solution. When H2SO4 is dissolved in water, it dissociates into hydrogen ions (H+) and sulfate ions (SO4 2-).

The hydrogen ions are the source of the acidity in the solution, as they can react with water molecules to form hydronium ions (H3O+). The hydronium ions are responsible for the characteristic sour taste and corrosive properties of acids.

Sulfuric acid is used in a wide range of industrial processes, including the production of fertilizers, detergents, and chemicals.

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Approximately, 259.2 grams of potassium bromide can dissolve at 324 grams of water in 55 degrees

What is potassium bromide?

Potassium bromide is a salt that is formed from the elements potassium and bromine. It is a white crystalline solid with a salty taste and is soluble in water.

Potassium bromide has a wide range of applications, including its use as a medication to treat epilepsy and as a sedative for animals. It is also used in the production of photographic paper, as a flame and in the preparation of various chemicals.

Therefore, 259.2 grams of potassium bromide can dissolve at 324 grams of water in 55 degrees

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SN

1:1

So lf you multiply N with 4 you have to multiply the s with the same number

the answer Will be sS4N4

easy

Eons are the current name for the large units of time that make up the geologic time scale. Eons can be further broken down into eras, which are then further broken down into periods.

The evolution of life on Earth is frequently depicted alongside the geologic time scale. It occasionally also refers to significant occurrences on Earth, such as the creation of the world's great mountains or the demise of the dinosaurs.

1. Since fossils revealed similar organisms coexisting on Earth at various periods of time, scientists divided Earth's history into several periods. To keep track of how Earth has changed, they gave each period of time a name.

For instance, the Jurassic period included a large number of dinosaurs. Fossils of the planet's very earliest green vegetation from the Ordovician period have been discovered. European scientists made up a large portion of those who originally gave historical periods on Earth names.

2. During the Precambrian age in earth, multicellular organisms are believed to be evolved. The development of life significantly started at the Precambrian era.

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Advancements in chemistry have played a critical role in advancing technology in a number of ways such as ;

Overall, advancements in chemistry are essential for developing new technologies and improving existing ones. By understanding the fundamental properties of materials and substances, chemists can create new materials with unique properties and develop new technologies that can improve our lives.

In term of Energy, Chemistry is crucial for developing new forms of energy, including renewable energy sources like solar, wind, and biofuels. Chemistry also plays a vital role in energy storage, such as the development of high-capacity batteries and fuel cells.

In term of Pharmaceuticals, Chemistry is essential for developing new drugs and improving existing ones. For example, the development of new cancer drugs has revolutionized cancer treatment, and new antibiotics have been developed to combat drug-resistant bacteria.

In term of Nanotechnology, Chemistry is critical for the development of nanotechnology, which involves working with materials at the nanoscale. Nanotechnology has many potential applications, including in electronics, medicine, and energy storage.

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Balancing a chemical equation involves adjusting the coefficients in front of the reactants and products so that the number of atoms of each element is equal on both sides of the equation.

Here is a general method for balancing chemical equations:

Write the unbalanced chemical equation, using chemical symbols and formulas to represent the reactants and products.

Count the number of atoms of each element on both sides of the equation.

Start by balancing the atoms of elements that occur in only one compound on each side of the equation.

Use coefficients to adjust the number of atoms of each element until they are equal on both sides of the equation.

Verify that the coefficients are in the lowest possible ratio and that the equation is balanced.

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All molecules have equally strong bonds is not true of a molecule.

Strong covalent bonds hold atoms in molecules together, whereas weak intermolecular forces of attraction hold individual molecules together.

Ionic and covalent bonds are often regarded as strong bonding. But atoms or molecules can also unite to establish other, more transient relationships. London dispersion forces and hydrogen bonds are two examples of weak bonds that are frequently observed in biology.

Although the atoms in each molecule have strong bonds holding them together, the forces of attraction between molecules are often very weak. Usually gases, such covalent compounds include HCl, SO2, CO2, and CH4. There are weak attraction forces present in molecular structures.

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Answer:by brig correct

Explanation:

The density of a substance is its mass divided by volume. The density of the substance with a mass of 108.75 g and volume of 75 ml is 1.45 g/ml.

The density of a substance is the  measure of its mass per unit volume. Density describes how closely its particles are packed. The density of a substance depends on the bond type, molecular weight, temperature and pressure as well.

The floating property of a substance on a fluid depends on its density. If it has less density than the fluid it will float on it.

Given,

the mass of the object m = 108.75 g

volume = 75 ml

density = mass/ volume

d = 108.75 g /75 ml

   = 1.45 g/ml.

Therefore, the density of the substance with the mass of 108.75 g and 75 ml volume is 1.45 g/ml.

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Explanation:

Refer to pic............

Answer:

25.0 grams of propane (C3H8) reacts with 25.0 grams of oxygen according to the following equation: C3H8 (g) + 5O2 (g) arrow 3CO2 (g) +...

Explanation: