The percent composition of a given element in a compound is the number of _______ in one mole of that compound.

a. The chemical equation for the electrolysis of water is:

2H2O(l) → 2H2(g) + O2(g)

b. The gas obtained at the anode during the electrolysis of water is oxygen (O2).

c. The volume of gas obtained at the anode is 0.002232 moles or approximately 0.05 L of oxygen gas.

a. The chemical equation for the electrolysis of water is:

2H2O(l) → 2H2(g) + O2(g)

b. The gas obtained at the anode during the electrolysis of water is oxygen (O2).

c. According to the balanced chemical equation, for every 2 moles of water (H2O) electrolyzed, 1 mole of oxygen gas (O2) is obtained. Since 1 mole of any gas occupies 22.4 L at standard temperature and pressure (STP), we can use the stoichiometry of the reaction to determine the volume of oxygen gas produced.

Given that 50 cm³ of gas is obtained at the anode, we need to convert this volume to liters:

50 cm³ = 50/1000 L = 0.05 L

Using the stoichiometric ratio of the balanced equation, we find that 2 moles of water produce 1 mole of oxygen gas. Therefore, 0.05 L of oxygen gas is equivalent to:

0.05 L × (1 mole/22.4 L) = 0.002232 moles

Thus, the volume of gas obtained at the anode is 0.002232 moles or approximately 0.05 L of oxygen gas.

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Answer:si and ge

Explanation:

Both silicon (Si) and arsenic (As) have 5 valence electrons. This means that they both have 5 dots around their chemical symbols in their electron dot diagrams. Thus, option B is correct. The images are attached below.

Phosphorus (P) has 5 valence electrons, but it also has a ground state electron configuration of 1s²2s²2p⁶3s²3p³. This means that phosphorus has 3 dots around its chemical symbol in its electron dot diagram, and 2 dots that are not shown.

Sulfur (S) has 6 valence electrons, but it also has a ground state electron configuration of 1s²2s²2p⁶3s²3p⁴. This means that sulfur has 4 dots around its chemical symbol in its electron dot diagram, and 2 dots that are not shown. Thus, option B is correct.

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Answer:

0.8853 mL

Explanation:

First we convert 13 lb to kg, keeping in mind that 1 lb = 0.454 kg:

Then we calculate how many mg of acetaminophen should be given, using the recommended dose and infant mass:

Finally we calculate the required mL of suspension, using its concentration:

Answer:

C. A physical change.

Explanation:

A liquid is cooled during an investigation causing it solidify.Which of the following most likely occurred?

A. Absorption of heat. NO. Heat was released.

B. A chemical change. NO. It was a physical change

C. A physical change. YES. The physical change is called solidification.

D. Formation of a new compound. NO. This would be a chemical change.

Approximately 70.57 mL of 1.00 M NaOH should be added to 250 mL of 0.50 M CH3CO₂H to produce a buffer with a pH of 4.50.

To determine the volume of 1.00 M NaOH required to produce a buffer with a pH of 4.50 when added to 250 mL of 0.50 M CH3CO₂H, we need to consider the Henderson-Hasselbalch equation and the stoichiometry of the reaction.

The Henderson-Hasselbalch equation for a buffer solution is given as:

pH = pKa + log([A-]/[HA])

In this case, CH3CO₂H (acetic acid) acts as the weak acid (HA) and CH3COO- (acetate ion) acts as its conjugate base (A-). We are given that the desired pH is 4.50, and we can determine the pKa value for acetic acid from reference sources, which is approximately 4.75.

Using the Henderson-Hasselbalch equation, we can rearrange it to solve for the ratio [A-]/[HA]:

[A-]/[HA] = 10^(pH - pKa)

[A-]/[HA] = 10^(4.50 - 4.75) = 10^(-0.25) = 0.5623

This means that the ratio of the acetate ion to acetic acid in the buffer solution should be approximately 0.5623.

To calculate the required volume of NaOH, we need to consider the stoichiometry of the reaction. Acetic acid reacts with hydroxide ions (OH-) to form acetate ions and water:

CH3CO₂H + OH- → CH3COO- + H2O

The stoichiometric ratio between acetic acid and hydroxide ions is 1:1. Therefore, the volume of 1.00 M NaOH needed can be calculated using the equation:

Volume (NaOH) × 1.00 M = Volume (CH3CO₂H) × 0.50 M × 0.5623

Volume (NaOH) = (Volume (CH3CO₂H) × 0.50 M × 0.5623) / 1.00 M

Volume (NaOH) = (250 mL × 0.50 M × 0.5623) / 1.00 M

Volume (NaOH) ≈ 70.57 mL

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your answer is C you're welcome

To solve such this we must know the concept of combination reaction. Therefore, the given reaction CH\(_4\)+Br\(_2\) \(\rightarrow\)CH\(_3\)Br+ HBr is a combination reaction.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

CH\(_4\)+Br\(_2\) \(\rightarrow\)CH\(_3\)Br+ HBr

The above reaction is a combination reaction. In combination reaction, more than one reactant combine to form a product. Because new chemicals are created during combination reactions, they are often referred to as synthesis.

Therefore, the given reaction is a combination reaction.

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Answer:

b

Explanation:

Answer:

Explanation:

This happens when water is boiled. Boiling the water causes the precipitation of solid calcium carbonate or solid magnesium carbonate. This removes the calcium ions or magnesium ions from the water, and so removes the hardness.

Answer:

Ground water

Explanation:

The ground water reservoir is found underground in cracks and spaces in the soil, sand and rock.

Ground water is a very important portion of the water cycle where water is stored in an aquifer.

Aquifers are porous and permeable formations that stores ground water within them.

In this manner, ground water system is recharged by infiltration of water from the surface. Water percolates and collects inside an aquifer in this manner.

Answer:

Ground Water

Explanation:

Answer:

So... for the element of SODIUM, you already know that the atomic number tells you the number of electrons. That means there are 11 electrons in a sodium atom. Looking at the picture, you can see there are two electrons in shell one, eight in shell two, and only one in shell three.

Explanation:

brainliest pleaseeee <3

Answer:

so there would be 2 electrons because

Explanation:

sodium has 11 electrons but if you look at the shels it onl has one electron (from the image im looking at) and the other shell only have one so theres 2 electrons

BaSO4 (s) + Cu(NO3)2 (aq)  and KCl (s) + Mg3(PO4)2 (s) is the product of given precipitation reactions.

Ba(NO3)2 (aq) + CuSO4 (aq) → BaSO4 (s) + Cu(NO3)2 (aq)

 K3 PO4 (aq) + MgCl2 (aq) → KCl (s) + Mg3(PO4)2 (s)

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Answer:

The number of these organisms in the soil would decrease.

Explanation:

Answer:

Jaheem has a goal running a total of 125 miles this month. Each day that he ran, he ran 7 miles. Which expression could Jaheem use to determine how many miles he has left to run after running for d days?

x a.

125 – 7d

x b.

7d + 125

x c. fraction numerator 125 over denominator 7 d end fraction

x d.

7dExplanation:Jaheem has a goal running a total of 125 miles this month. Each day that he ran, he ran 7 miles. Which expression could Jaheem use to determine how many miles he has left to run after running for d days?

x a.

125 – 7d

x b.

7d + 125

x c. fraction numerator 125 over denominator 7 d end fraction

x d.

7d

The number of the atoms that should be the numerator is 6.02 * 10^23 atoms.

We have to note that the conversion factor is the factor that can be used in the conversion of one unit to the other. We have to note that if we are able to change the unit then we can be able to make the conversion.

We have to note that the Avogadro's number is the number of atoms that we can find in one mole of a substance and it has a value of about 6.02 * 10^23 atoms in the atom of magnesium.

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Approximately 4.37 x 10^23 molecules of HCl would be required to form 34.52 g of MgCl₂.

To determine the number of molecules of HCl required to form 34.52 g of MgCl₂, we need to use the molar mass and stoichiometry of the balanced equation:

Mg(OH)₂(s) + 2 HCl(aq) → 2 H₂O(l) + MgCl₂(aq)

The molar mass of MgCl₂ is 95.21 g/mol.

First, we need to calculate the number of moles of MgCl₂ formed:

Moles of MgCl₂ = mass of MgCl₂ / molar mass of MgCl₂

Moles of MgCl₂ = 34.52 g / 95.21 g/mol

Moles of MgCl₂ = 0.363 mol

According to the balanced equation, the stoichiometric ratio between HCl and MgCl₂ is 2:1. Therefore, the moles of HCl required can be calculated as follows:

Moles of HCl = 2 * Moles of MgCl₂

Moles of HCl = 2 * 0.363 mol

Moles of HCl = 0.726 mol

To calculate the number of molecules, we need to use Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol.

Number of molecules of HCl = Moles of HCl * Avogadro's number

Number of molecules of HCl = 0.726 mol * 6.022 x 10^23 molecules/mol

Number of molecules of HCl = 4.37 x 10^23 molecules

Therefore, approximately 4.37 x 10^23 molecules of HCl would be required to form 34.52 g of MgCl₂.

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In 4.38 × 10^21 molecules of water, there are approximately 0.073 moles.

To calculate the number of moles, we can use Avogadro's number, which states that 1 mole of a substance contains 6.022 × 10^23 molecules. So, by dividing the given number of molecules (4.38 × 10^21) by Avogadro's number, we can find the number of moles.

Now, let's explain the process in detail. Avogadro's number is a constant that represents the number of particles (atoms, molecules, etc.) in one mole of a substance. It is approximately 6.022 × 10^23. Therefore, if we divide the given number of molecules by Avogadro's number, we can determine the number of moles.

In this case, we divide 4.38 × 10^21 molecules by 6.022 × 10^23 molecules/mole, resulting in approximately 0.073 moles.

Significant figures play an important role in reporting the answer. The given number of molecules has three significant figures (4, 3, and 8), so our answer should be reported with three significant figures as well. Therefore, the number of moles is approximately 0.073.

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Metamorphic rock formation involves the transformation of existing rocks under heat and pressure. They form without melting and can appear foliated or non-foliated.

Metamorphic rocks are formed from the transformation of existing rock types in a process called metamorphism, which means 'change in form'. The appropriate phrases that describe metamorphic rock formation are: 'form from existing rocks', 'form without melting', 'appear foliated or non-foliated', and 'require heat and pressure to form'. These rocks are subject to conditions of heat and pressure that cause them to change physically and/or chemically, resulting in a new type of rock. They can either be foliated (layered) or non-foliated. Importantly, metamorphic rock formation does not include a liquid state, meaning they do not 'form from liquid rock' or 'form from deposition'.

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Answer:

his mother died i think

Explanation:

Although he was not accepted, his mother was determined to give her son a first-class education and they walked to St. Petersburg. Dmitri was accepted into the Institute of Pedagogy on a full scholarship. That same year his mother died and at the age of sixteen, Dmitri was orphaned.

An atom's mass is determined by its protons and neutrons.

An atom's charge is determined by its number of protons minus it number of electrons.

Atoms become cations, or positively charged when they lose an electron, and since electrons have a negative charge, they become anions, or negatively charged.

Water is a universal solvent.

Carbohydrates (carbs) are used by the body for energy.

Steroids and triglycerides are lipids.

Proteins that catalyze chemical reactions are called enzymes.

Answer:

The answer is (e) none of the above. The combined gas law relates the pressure, volume, and temperature of a gas, so all three variables (pressure, volume, and temperature) must be considered and at least one of them should be held constant to use the combined gas law. The mass of the gas sample, number of moles of gas, and number of gas molecules are not directly related to the combined gas law.

Answer:

A

Explanation:

We are given that the molar mass of boron triflouride BF₃ is 67.81 g/mol. We want to determine the number of molecules of BF₃ in 2 g of BF₃.

Recall that there are 6.02 × 10²³ molecules in any mole of a substance. In other words, there are 6.02 × 10²³ BF₃ molecules in a mole of BF₃. Starting with the initial value, multiply:

\(\displaystyle \begin{aligned} 2\text{ g BF$_3$}&\cdot \frac{1\text{ mol BF$_3$}}{67.81 \text{ g BF$_3$}} \cdot \frac{6.02\times 10^{23} \text{ molecules BF$_3$}}{1 \text{ mol BF$_3$}} \\ \\ &= 1.776 \times 10^{22} \text{ molecules BF$_3$}\end{aligned}\)

Hence, our answer is A.

*Perhaps it rendered the values incorrectly, but since we started with only 2 g of BF₃, our resulting calculation should only contain one significant digit. Hence, the correct answer should be 2 × 10²² molecules of BF₃.

The molecules of  BF₃ that are there in 2 g is 1.776 × 10²² molecules and the correct option is option A.

The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter.

A mole is defined as the amount of substance containing the same number of atoms, molecules, ions, etc. as the number of atoms in a sample of pure 12C weighing exactly 12 g.

Given,

Molar mass of BF₃ = 67.81 g/mol

Mass = 2g

Moles = mass / molar mass

= 2 / 67.81

= 0.029 moles

1 mole = 6.023 × 10²³

0.029 moles = 6.023 × 10²³ × 0.029

= 1.776 × 10²² molecules

Thus, the ideal selection is option A.

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Algal blooms and high concentrations of nitrogen in water are effects of water pollution. Overgrazing and the use of chemical fertilizers cause water pollution.

Algal blooms are an effect of water pollution. They occur when there is an excessive amount of nutrients, particularly nitrogen and phosphorus, in the water due to pollution. The overgrowth of algae depletes the oxygen levels in the water, which can harm fish and other aquatic animals.

Overgrazing can cause water pollution by increasing the sedimentation rate of waterways. This sedimentation can carry nutrients, bacteria, and other pollutants into the water, which can degrade water quality and cause harm to aquatic life.

The use of chemical fertilizers to enhance production is a cause of water pollution. When fertilizer is overused, it can leach into waterways and cause nutrient pollution, which can lead to algal blooms and other forms of water pollution.

High concentrations of nitrogen in water are often an effect of water pollution. This can be caused by the overuse of fertilizers or the discharge of untreated sewage into waterways. High nitrogen levels can cause algal blooms, which can lead to oxygen depletion and harm aquatic life.

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Answer:

Cause:

: : use of chemical fertilizers to enhance production

: : overgrazing

Effect:

: : high concentration of nitrogen in water

: : algal blooms

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The volume of 0.100M NaCl that would be required to make a 0.0350M solution of NaCl when diluted to 150.0mL with water is 52.5mL.

The volume of a diluted solution can be calculated using the following formula;

CaVa = CbVb

Where;

According to this question, 0.100M NaCl would be required to make a 0.0350M solution of NaCl when diluted to 150.0mL with water. The volume can be calculated as follows:

0.1 × Va = 0.0350 × 150

0.1Va = 5.25

Va = 52.5mL

Therefore, 52.5mL is the volume required to dilute the sodium chloride solution.

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The rate constant of the second-order reaction is 0.111 M^-1 min^-1.

The given data represents a second-order reaction where the rate of the reaction is proportional to the square of the concentration of A.

The integrated form of the second-order reaction is:

1/[A]t = kt + 1/[A]0

where [A]t and [A]0 are the concentrations of reactant A at time t and time zero, respectively, k is the rate constant.

We can use the given information to calculate the rate constant (k) of the reaction for the given half-life (t1/2) of 3.15 minutes:

t1/2 = (1 / k[A]0)

Using the percentage decrease in concentration and the given initial concentration, we can calculate the concentration of A at time t:

[A]t = [A]0 - 0.30[A]0 = 0.57126 M

Substituting the given values, we get:

3.15 min = (1 / k)(0.0818 M) / (0.0818 M - 0.57126 M)

Simplifying the equation above, we can solve for k:

k = 0.111 M^-1 min^-1

Therefore, the rate constant of the second-order reaction is 0.111 M^-1 min^-1.

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Answer:

n = 1.075  moles

Explanation:

Given that,

Mass of oxygen = 34.4 gram

The molar mass of oxygen gas = 32 g/mol

We need to find the number of moles of oxygen. We know that,

No. of moles = given mass/molar mass

So,

\(n=\dfrac{34.4\ g}{32\ g/mol}\\\\=1.075\ mol\)

So, there are 1.075  moles in 34.4 g of Oxygen gas.

Answer:

1. is Molar (with capital M)

2. is molal (m)

Explanation:

By definition, 1 Molar solutions have 1 mol of solute in 1 L of solution and 1 molal solutions have 1 mol of solute in 1 Kg of solvent

A liquid substance that could be used in the laboratory for dissolving dry mortar on floor tiles is vinegar; (i) removing KMnO₄, stains is sodium metabisulfite solution; drying acid anhydrides is concentrated sulfuric acid.

Solvents are substances usually liquids, but may also be gases or solids that dissolve other substances known as solutes.

Solvents are usually used as cleansing agents.

One possible liquid substance that could be used for dissolving dry mortar on floor tiles is a mild acid solution, such as diluted hydrochloric acid or vinegar.

KMnO₄ stains are often difficult to remove, but one substance that can be used is sodium metabisulfite (Na₂S₂O₅) solution. Sodium metabisulfite acts as a reducing agent and can effectively neutralize and remove KMnO₄ stains.

Concentrated sulfuric acid is commonly used in the laboratory as a drying agent. It has a strong affinity for water and can efficiently absorb moisture, including water present in acid anhydrides.

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Answer:

The answer to these are:

(A) 32

(B) If it is balanced 32

(C) 80

Explanation: