Is toasting marshmallows over a campfire a physical or chemical change?

CaCO3(s) ⟶ CaO(s)+CO2(s) 

moles CaCO3: 1.31 g/100 g/mole CaCO3= 0.0131 

From stoichiometry, 1 mole of CO2 is formed per 1 mole CaCO3, therefore 0.0131 moles CO2 should also be formed. 
0.0131 moles CO2 x 44 g/mole CO2 = 0.576 g CO2 

Therefore:
% Yield: 0.53/.576 x100= 92 percent yield

Answer : The percent yield for this reaction is, 91.9 %

Solution : Given,

Mass of carbon dioxide = 0.53 g

Mass of calcium carbonate = 1.31 g

Molar mass of carbon dioxide = 44 g/mole

Molar mass of calcium carbonate = 100 g/mole

First we have to calculate the moles of [tex]CaCO_3[/tex].

[tex]\text{Moles of }CaCO_3=\frac{\text{Mass of }CaCO_3}{\text{Molar mass of }CaCO_3}=\frac{1.31g}{100g/mole}=0.0131moles[/tex]

Now we have to calculate the mass of carbon dioxide.

The balanced chemical reaction is,

[tex]CaCO_3(s)\rightarrow CaO(s)+CO_2(g)[/tex]

From the balanced reaction we conclude that

As, 1 mole of [tex]CaCO_3[/tex] react to give 1 mole of [tex]CO_2[/tex]

So, 0.0131 mole of [tex]CaCO_3[/tex] react to give 0.0131 mole of [tex]CO_2[/tex]

Now we have to calculate the mass of carbon dioxide.

[tex]\text{Mass of }CO_2=\text{Moles of }CO_2\times \text{Molar mass of }CO_2[/tex]

[tex]\text{Mass of }CO_2=(0.0131mole)\times (44g/mole)=0.5764g[/tex]

Now we have to calculate the percent yield for this reaction.

[tex]\%\text{ yield of }CO_2=\frac{\text{Actual yield of }CO_2}{\text{Theoretical yield of }CO_2}\times 100=\frac{0.53g}{0.5764g}\times 100=91.9\%[/tex]

Therefore, the percent yield for this reaction is, 91.9 %

There are 0.538 moles of ¹³C atoms in the given 7.00 g sample.

This is a simple mole conversion problem.  It requires the molar mass, or the mass of one mole of a substance, of carbon - 13, an isotope of carbon. An isotope is like a different version of a specific atom. In this case, carbon - 13 is a version of a carbon atom that has one more neutron than the normal carbon atom. It is a little heavier than the normal carbon atom because of its extra neutron.

To convert from grams of sample to moles of sample, the general equation is:

[tex]moles \ of \ sample = \frac{given \ mass}{molar \ mass}[/tex]

To convert 7.00 g of ¹³C, the equation is:

[tex]mole \ of \ ^{13}C \ = \frac{7.00 \ g}{13.00 \ \frac{g}{mol}} \\\boxed {mole \ of \ ^{13}C \ = 0.53846 \ mol}[/tex]

Since there is only 3 significant figures in the given, the final answer must also have 3 significant figures. Therefore,

[tex]\boxed {\boxed {mole \ of \ ^{13}C \ = 0.538 \ mol \ or \ 5.38 \times 10^{-1} \ mol}}[/tex]

This answer is logical since one mole of ¹³C will have a mass of 13.00 g. The given sample (7.00 g) is less than 13.00 g so the mole equivalent of that should be less than one mole.

Answer:

Carbon

Explanation:

Answer:

1.4.90 × 1019 J

or

2.  3.01 × 10-19 J

or

3.  7.30 × 10-19 J

or

4.  3.32 × 1028 J

Explanation:

There are many gases in the atmosphere, that are harmful. Out of all gases carbon dioxide is the one.  By plantation we can decrease the amount of carbon in atmosphere.

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same. Two or more than two atoms with different physical or chemical properties can not combine together to form an element.

Carbon is release in large quantity around us on burning of fuels form of carbon dioxide. Carbon in our atmosphere is not good for us . So there is need to decrease the amount of carbon in atmosphere. The only way to decrease the amount of carbon in atmosphere is by increase plantantion.

Therefore, by plantantion we can decrease the amount of carbon in atmosphere.

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In the reaction NH₄⁺ + OH⁻  yielding NH₃ + H₂O, NH₄⁺ acts as the Brønsted-Lowry acid by donating a proton to OH⁻, thus forming NH₃ and H₂O.

In the chemical reaction NH₄⁺ + OH⁻ yielding NH₃ + H₂O, the substance acting as the Brønsted-Lowry acid is NH₄⁺. According to the Brønsted-Lowry theory, an acid is defined as a substance that donates a proton (H⁺ ion) to another substance. Since the NH₄⁺ ion donates a proton to the OH⁻ ion, forming NH₃ and H₂O, it is identified as the proton donor, or the Brønsted-Lowry acid, in this reaction. Conversely, the OH⁻ ion is the proton acceptor, making it the Brønsted-Lowry base.

Most Brønsted-Lowry acid-base reactions can be viewed in this manner, where one acid and one base are reactants, and one acid and one base are products, indicating their respective roles in the transfer of protons.

Answer: reactivity of the copper strip

Explanation: A physical property is defined as the property which measures change in shape and  size.No new substance gets formed in a physical change.

Example: Density of copper strip, Odor of chlorine solution and color of the chlorine solution.

A chemical property is defined as the property which measures change in chemical composition. A new substance is formed in chemical reaction.

Example: reactivity of substance

Answer:

Reactivity of the copper strip

Explanation:

The matter properties can be classified as chemical property or physical property. The first refers to the properties that, when analyzed, change the composition of the matter, it means that a chemical property is a capacity of a substance to transform in other, such as the combustibility (the property to react with a comburent to form carbonic gas), the oxidation, and in general the reactivity.

The physical properties are the ones that are possible to be analyzed without changing the composition of a substance, such as the color, the density, the odor, and the pH.

So, the density of the copper strip, odor of the chlorine solution, and color of the chlorine solution are physical properties, and the reactivity of the copper strip is a chemical property.

Answer: The given statement is false.

Explanation:

When an element chemically combines with another element then it results into the formation of a molecule or a compound.

A compound is defined as the substance in which different elements are chemically combined together in a fixed ratio by mass.

For example, [tex]MgSO_{4}[/tex] is a compound and elements are present in 1:4 ratio.

A compound can be divided into its constituent or simpler substances by chemical means.

And, a molecule is defined as the substance in which two or more same type of elements chemically combine together in a fixed ratio by mass.

For example, [tex]O_{3}[/tex], [tex]Cl_{2}[/tex] etc are molecules.

Therefore, we can conclude that the statement two or more atoms bonded together always form a compound, is false.

Equilibrium

Answer:

See explanation.

Explanation:

Hello,

In this case, an excited state means is referred to the valence electron that has moved from its lower state orbital, at which the lowest available energy is present, to another orbital with higher energy.

In this manner, any electron configuration in which the last electron is located at an orbital with higher energy, stands for an element at an excited state.  For instance, looking at the lower state of nitrogen, the resulting electron configuration turns out:

[tex]1s^22s^22p^3[/tex]

Now, by exciting the element, an electron could occupy a large number of orbitals. Nonetheless, it will occupy the next available one, as shown below:[tex]1s^22s^22p^23s^1[/tex]

Wherein the valence electron is now at the [tex]3s[/tex] orbital in the so called excited state.

Best regards.

You will need to calculate the mass of KI you will need to dissolve in water in order to prepare the solution. The mass could be calculated by converting 100 ml to L then multiplying that to the target molarity of the solution which is 1.0 m. Then multiply it with the molecular weight of KI which is 166 g. Thus, you will need to dissolve 16.6 grams of KI to 100 ml water. 

Answer:

Weight 16.6 g of KI, dissolve it in water, transfer to a volumetric ball of 100 mL and complete the volume with water.

Explanation:

You must be careful with concentrations. First we have molarity, represented by a capital M, and then we have molality, represented by a lowercase m; they are defined next:

Molarity = M = moles of solute/ Liters of solution

Molality = m = moles of solute / Kg of solvent

if we were talking about molality, the problem wouldn’t be so easily resolve since they don´t give us the mass of solvent to be use but the volume of solution need and you will need the solution’s density to have an approximation of the mass solvent.

For this reason, I’m assuming we are talking about molarity. To solve the problem, we need to find the amount of KI we need to prepare the solution, for this we use the equation of molarity:

M = moles KI / Liters of solution

With this we can find the moles of KI needed:

Moles KI = M x liters of solution

Replacing the values:

Moles KI = 1.0 M x 0.1 L = 0.1 moles of KI

Note that 100 mL = 0.1 L. Now we need the grams of KI to be weighted. Using its molecular mass, which is 166 g/mol, we have:

[tex]0.1 mole KI \frac{166 g KI}{1molKI} = 16.6 g KI[/tex]

Then, we need to weight 16.6 g of KI, dissolve it in water (about 50 mL), transfer to a volumetric ball of 100 mL and complete the volume with water.

Final answer:

The bond length in[tex]F_{2}[/tex] is shorter than expected due to electron-electron repulsion and the influence of molecular orbitals, which lead to a bond length that doesn't simply equate to twice the atomic radius of fluorine.

Explanation:

The bond length in [tex]F_{2}[/tex] is shorter than twice the atomic radius of F because of electron-electron repulsion within the molecule. The process of bond formation involves not just the attraction between the electrons and nuclei but also the repulsion between the nuclei themselves and the electron pairs. When two fluorine atoms approach each other, their unpaired electrons in their outermost shells pair up to form a covalent bond, and due to fluorine's high electronegativity and small size, there is significant repulsion between these electrons when they are in close proximity. Additionally, when considering bond lengths, it is important to note that molecular orbital theory and experimental data both play a role in understanding the nature of bonds. The molecular orbital theory, which considers both bonding and antibonding orbitals, predicts a single bond for [tex]F_{2}[/tex]  as confirmed by the experimental bond order. Therefore, the combination of these repulsive forces and the nature of the molecular orbitals involved results in a bond length that is shorter than the sum of two fluorine atomic radii.

The man who created the original version of the modern Periodic Table of Elements is no other than Dmitri Mendeleev (1834 – 1907). He was a Russian chemist and inventor. Taken from his name, the element Mendelevium (symbol Md, atomic number 101) is named to him in his honor.

Answer:

 Mendelevium (Md)

Mendelevium, with atomic number 101, is named after Dmitri Mendeleev who created the first periodic table and arranged elements predicting future discoveries.

The element named after Dmitri Mendeleev, the man credited with creating the first periodic table, is called mendelevium. With an atomic number of 101, mendelevium was synthesized in 1955, which was several years after Mendeleev's death. Mendeleev's table arranged elements by atomic mass and left spaces for undiscovered elements, which showed his predictive insight into the chemical properties of elements. His version of the periodic table was significant due to its ability to predict new elements and their properties.

Final answer:

The kinetic energy of emitted electrons can be calculated using the photoelectric effect equation, but it requires knowledge of cesium's work function, which is not provided in the question.

Explanation:

The kinetic energy of the emitted electrons when cesium is exposed to UV rays of frequency 1.6×1015Hz can be determined using the photoelectric effect and Planck's equation. According to the photoelectric effect, the energy of the emitted electrons is given by the equation Ek = hν - Φ, where Ek is the kinetic energy, h is Planck's constant (6.626 × 10-34 J·s), ν is the frequency of the incident light, and Φ is the work function of the metal (energy required to remove an electron from the surface). If the work function of cesium is known, one can simply plug in the values to calculate Ek. Without the work function value, a specific numerical answer cannot be provided.

Magnesium combines with oxygen to form magnesium oxide, which is characterized by the chemical formula MgO. The reaction is facilitated by the burning of magnesium in the presence of oxygen. This reaction highlights magnesium's strong affinity for oxygen.

The element from the periodic table that combines with oxygen to form magnesium oxide is magnesium. This is derived from the chemical formula for magnesium oxide, which is MgO. Here, Mg represents magnesium and O represents oxygen. The reaction to create magnesium oxide typically occurs when magnesium is burnt in the presence of oxygen, as illustrated by the chemical reaction: 2Mg(s) + O₂(g) → 2MgO(s). This reaction shows that magnesium and oxygen combine to form magnesium oxide.

Magnesium is recognized for its potency in chemical reactions, particularly in those involving oxides. When magnesium burns, it reacts with carbon dioxide to produce elemental carbon, demonstrating magnesium's significant affinity for oxygen.

Moreover, many of the common salts of the alkaline earth metals like magnesium are insoluble in water due to their high lattice energies and these compounds' divalent metal ions.

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The relative atomic mass of potassium is 39.10 amu, and so its molar mass is 39.10 g/mol.

The relative atomic mass, also known as atomic weight, is a measure of the average mass of a chemical element's atoms. It is given relative to the mass of a carbon-12 atom, which has a relative atomic mass of 12 atomic mass units (u). This unit of atomic mass is commonly employed because carbon-12 is a stable and common isotope whose mass can be precisely determined. The atomic mass of K is 39.10 amu, and so its molar mass is 39.10 g/mol.

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The relative atomic mass and molar mass of potassium (K) are both 39.10. To calculate the number of moles from a given mass, divide the mass by the molar mass; e.g., 4.7 g of K is approximately 0.12 mol.

The relative atomic mass and the molar mass of the element potassium (K) are both 39.10 to two decimal places. To find the number of moles of potassium based on a given mass, we use the formula:

Number of Moles = \( \frac{{Mass \, (g)}}{{Molar \, Mass \, (g/mol)}} \)

As an example, for a mass of 4.7 g of potassium:

Number of Moles = \( \frac{{4.7 \, g}}{{39.10 \, g/mol}} \) = 0.12 mol

This value is consistent with the ballpark estimate that since the mass of potassium is a bit more than one-tenth of its molar mass, the number of moles would be slightly greater than 0.1 mol.

To contain the same number of atoms also mean to contain the same number of moles. So let us say that X is the mass of Silver Ag required, so that:

X / 107.87 = 10 / 10.81

X = 99.79 g

Answer: The mass of silver atoms is 99.78 grams.

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]      .....(1)

For boron:

Given mass of boron = 10.0 g

Molar mass of boron = 10.81 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of boron}=\frac{10.0g}{10.81g/mol}=0.925mol[/tex]

As, the number of atoms of silver are same as the number of atoms of boron. This means that number of moles of boron will be same as number of moles of silver.

Now, calculating the mass of silver atoms by using equation 1, we get:

Molar mass of silver = 107.87 g/mol

Moles of silver = 0.925 moles

Putting values in equation 1, we get:

[tex]0.925mol=\frac{\text{Mass of silver}}{107.87g/mol}\\\\\text{Mass of silver}=99.78g[/tex]

Hence, the mass of silver atoms is 99.78 grams.

The secondary structure of proteins, including the α-helix and β-pleated sheet, is maintained by hydrogen bonds between the oxygen atom in the carbonyl group of one amino acid and the hydrogen of an amide group in another amino acid.

The secondary structure of a protein is maintained by hydrogen bonds that form between parts of the peptide backbone. This involves the oxygen atom in the carbonyl group of one amino acid and the hydrogen of an amide group in another amino acid that is typically four residues down the chain. The most common secondary structures are the α-helix and the β-pleated sheet. The α-helix is characterized by a coiled arrangement maintained by hydrogen bonds between every fourth amino acid. In the β-pleated sheet, hydrogen bonds form between sections of the polypeptide chain that lie parallel or antiparallel to each other, creating a folded 'sheet' appearance.

A substance and a solution are similar in that they both consist of matter composed of atoms, ions, or molecules, but they differ in that a substance refers to any specific type of matter, while a solution is a specific type of mixture that consists of a solvent and a solute.

A substance and a solution are similar in that they both consist of matter composed of atoms, ions, or molecules. They are different in that a substance refers to any specific type of matter, while a solution is a specific type of mixture that consists of a solvent and a solute. Solutions are homogeneous mixtures, meaning that the solute molecules are distributed evenly throughout the solvent. For example, when you dissolve sugar in water, the sugar molecules are separated by water molecules and evenly distributed throughout the solution.

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Final answer:

The boiling point of water is 100°C and is an intensive property because it does not change with the amount of water. Intensive properties do not vary with the quantity of substance, while extensive properties do.

Explanation:

The boiling point of a substance is the temperature at which it changes from a liquid to a gas. For water, this temperature is 100°C under standard atmospheric pressure (1 atm). Whether we have 250 ml or 1000 ml of water, the boiling point remains the same and is an example of an intensive property. This is because intensive properties do not depend on the amount of substance present.

Regarding extensive and intensive properties, temperature is an example of an intensive property because it does not change when the amount of substance is doubled. On the other hand, an extensive property is dependent on the amount of substance (e.g., volume or mass). Combining two samples of water with the same temperature will result in a mixture of the same temperature, demonstrating that temperature is intensive.

When considering the ratio of two extensive properties, such as mass to volume to obtain density, the resultant property is intensive because it characterizes the property per unit amount, therefore not changing with the quantity of substance.