why would a percent yield be less than 100%? give a reason

Answer:

Explanation:

Option C is the correct answer

Among electromagnetic waves, UV rays are most dangerous because exposure to these radiation cause serious problems in living organism. Therefore, the correct option is option C.

Electromagnetic wave is a wave which contain two component one is electric component and other is magnetic component. The electric and magnetic component are perpendicular to each other. There are so many wave that comes under electromagnetic wave like infrared wave , radio wave.

There is a relation between energy of wave. frequency of wave, and wavelength of wave

Mathematically,

E=hc/λ

where,

E = energy of electromagnetic wave

h is planks constant having value 6.67×10⁻³⁴js

c is speed of light that is 3×10⁸m/s

λ is the wavelength of electromagnetic wave

An electromagnetic spectrum refer to a range of wavelengths of light that increases from one end to the other.

Therefore, the correct option is option C.

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Answer:

666.93 kJ

Explanation:

Using the formula;

Q = m × c × ∆T

Where;

Q = amount of heat absorbed (Joules)

m = mass of substance (g)

c = specific heat capacity (4.184 J/g°C)

∆T = change in temperature (°C)

Based on the information provided in the question;

Q = ?

m = 2000g

∆T = 99.7 °C - 20 °C = 79.7 °C

c = 4.184 J/g°C

Using Q = m × c × ∆T

Q = 2000 × 4.184 × 79.7

Q = 666929.6 Joules

To calculate the amount of heat absorbed (Q) in kilojoules (kJ), we say;

1 joule = 0.001 kilojoule

666929.6 Joules = 666929.6 × 0.001

= 666.9296 KJ

Approximately, Q = 666.93 kJ.

Answer:

150 moles (2 sig. figs.)

Explanation:

to convert from ...

grams to moles => divide by formula weight

moles to grams => multiply by formula weight

this problem:

Given mass of Iron (Fe) = 8200g

formula wt of Fe = 56g/mole

moles = mass/formula wt = 8200g / 56g/mol = 146.42857 moles (calculator) = 150 moles (2 sig. figs.)

The number of moles in 8200 grams of iron is 57.69 moles of Fe.

Mole is defined as the amount of the substance containing the same number of discrete entities (atoms, molecules, ions, etc) as there are atoms in a sample of pure 12C weighing exactly 12g.

The number of particles present in one mole of any substance  is Avogadro Number and is equals to 6.023 x 10²³ particles.

Given ;

To find ;

Formula used :

             =  8200 / 56   (atomic weight of Fe = 56 gm)

             = 157.69 moles of Fe.

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Answer:

B

Explanation:

Generally, when you dilute something, your goal is to thin your concentration. Even if you added a solute, if your goal is dilution, it will make the concentration decrease.

Answer:

1. 10

Explanation

when litmus paper is blue that means the solution is basic and 10 on the pH scale is the most basic out of all your options

Answer:

The mass of oxygen gas required to produce 65.75 grams of steam is approximately 162.2 grams

Explanation:

From the question, we have the following chemical reaction equation;

2C₃H₁₈(l) + 25O₂ (g) → 16CO₂(g) + 18H₂O (g)

The molar mass of oxygen, O₂ = 32 g/mol

The molar mass of steam, H₂O = 18.01528 g/mol

25 moles of oxygen are required to produce 18 moles of steam

Therefore, according to  Proust's law of definite proportions;

(32 × 25) g of oxygen are required to produce (18 × 18.01528) g of steam

65.75 g of steam will be produced by (32 × 25)/(18 × 18.01528) × 65.75 g ≈ 162.2 g of oxygen O₂.

Answer:

3 NiSO₄(aq) + 2 (NH₄)₃PO₄(aq) ⇒ Ni₃(PO₄)₂ + 3 (NH₄)₂SO₄

Explanation:

The question is missing but I think it must be about writing and balancing the equation.

Let's consider the unbalanced reaction that occurs when aqueous solutions of nickel(II) sulfate and ammonium phosphate are combined to form solid nickel(II) phosphate and a solution of ammonium sulfate. This is a double displacement reaction.

NiSO₄(aq) + (NH₄)₃PO₄(aq) ⇒ Ni₃(PO₄)₂ + (NH₄)₂SO₄

We will start balancing Ni atoms by multiplying NiSO₄ by 3.

3 NiSO₄(aq) + (NH₄)₃PO₄(aq) ⇒ Ni₃(PO₄)₂ + (NH₄)₂SO₄

Now, we have to balance S atoms by multiplying (NH₄)₂SO₄ by 3.

3 NiSO₄(aq) + (NH₄)₃PO₄(aq) ⇒ Ni₃(PO₄)₂ + 3 (NH₄)₂SO₄

Then, we need to balance N atoms by multiplying (NH₄)₃PO₄ by 2. This will be the balanced equation.

3 NiSO₄(aq) + 2 (NH₄)₃PO₄(aq) ⇒ Ni₃(PO₄)₂ + 3 (NH₄)₂SO₄

Answer:

Is there a way you can give a answer made for a 5th grade

Explanation:

Answer:

1. Graphite rod (cathode)

2. Positive terminal

3. Solid zinc layer (anode)

4. Paste (reduction takes place here)

5. Negative terminal

Explanation:

This was the only thing i could find on it. hope this helps.

Answer:

Explanation:

• Label all parts.

1. Cathode or Graphite Rod

2. Positive terminal  

3. Anode or Solid Zinc layer  

4. Electrolyte Paste (reduction takes place here)

5. Negative Terminal (maybe this could also be the Zinc casing)  

• Label the cathode and the anode, including the charges on each.

The anode is the zinc layer is negatively charged and the cathode is the graphite rod is positively charged.  

• Show the flow of electrons.

The zinc casing is oxidized and the electrons flow along the zinc layer, into the negative terminal, and then out the negative terminal. The electrons move from the wire to the graphite rod. Then from the rod the electrons move to the paste, then the past goes through reduction. The anode gets a negative charge as electrons are released, and the cathode gets a positive charge as the electrons, which are negatively charged, are consumed.

• Explain how the cell works. Include the oxidation and reduction half-reactions in your explanation.

Alkaline dry cells use spontaneous oxidation-reduction reactions to convert chemical energy to electrical energy. According to the lesson ‘’Half-reactions are combined in a small casing, but still separated into half-cells.’’

Answer:

For an electron they start at the first level (n=1) In order to move up to the next level (n=2) the amount of quantom energy to move to this next level the energy must be perfect in order to move. If the quantom energy is to small the electron it doesn't try.

Answer: it is D

Explanation:

Scientists can model the effects of reactant concentration on the speed of a reaction With an atomic model. Hence, D is correct.

Atomic model, in physics, a model used to describe the structure and makeup of an atom. Atomic models have gone through many changes over time, evolving as necessary to fit experimental data. For a more in-depth discussion of the history of atomic models, see atom: development of atomic theory.

Scientists use models to study atoms because atoms are extremely small and can't even be seen. If atoms can't be seen, it's easier to study and predict what atoms will do with a representation of them.

Models are useful tools in learning science which can be used to improve explanations, generate discussion, make predictions, provide visual representations of abstract concepts and generate mental models.

Therefore, Scientists can model the effects of reactant concentration on the speed of a reaction With an atomic model. Hence, D is correct.

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Answer:

it's not clear

Explanation:

.

Answer:

Answer:

ph=2

Explanation:

Answer:

false the answer is woody

Explanation:

those are the two types of stems

4) H+ions is your answer , good morning , have a great day ahead.

Answer:

82.04g

Explanation:

To solve this problem, you need to find the molar mass of HCl, which is the sum of the molar mass of H plus the molar mass of Cl. The molar mass of H is 1.008g/mol while the molar mass of Cl is 35.45g/mol. Thusly the molar mass of HCl is 36.458g/mol. You have 2.25 moles of HCl, so multiply the number of moles by the molar mass to get the mass in g. In this case it is 2.25mol * 36.458g/mol = 82.04g.

If I helped, a brainliest would be greatly appreciated!

Answer:

as per given balanced equation one mole Zn produces 1mole Hydrogen

when reacted with excess acid.

So 3 moles Zn will give 3moles Hydrogen

Explanation:

According to the balanced chemical equation, one mole of Zn produces one mole of hydrogen . Therefore, 3.86 moles of Zn metal will produce 3.86 moles of hydrogen gas.

Mole ratio refers to the ratio of the number of moles of one substance in a chemical reaction to the number of moles of another substance in the same reaction.

It is derived from the balanced chemical equation for the reaction, which indicates the relative amounts of each substance involved in the reaction.

Mole ratio is important in stoichiometry, which is the study of the quantitative relationships between reactants and products in a chemical reaction.

The given chemical reaction is written as follows:

Zn + 2 HCl ⇒ ZnCl₂ + H₂

According to the balanced chemical equation, one mole of Zn produces one mole of hydrogen . Therefore, 3.86 moles of Zn metal will produce 3.86 moles of hydrogen gas.

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Answer:

P waves travel faster than other waves

Explanation:

P waves travel fastest and are the first to arrive from the earthquake. In S or shear waves, rock oscillates perpendicular to the direction of wave propagation. In rock, S waves generally travel about 60% the speed of P waves, and the S wave always arrives after the P wave.

Answer:

0.185 moles of AlN

Explanation:

The equation is:

2Al  +  N₂  →  2AlN

This reaction indicates that 2 mol of aluminum can react to 1 mol of nitrogen to produce 2 moles of aluminum nitride.

We convert the aluminum's mass to moles

5 g/ 26.98 g/mol = 0.185 moles.

2 moles of Al are needed to produce 2 moles of AlN

so, ratio is 1:1

In conclussion we say:

0.185 moles of Al, must produce 0.185 moles of AlN

Answer:

Hi ,

Answer:

A chemical energy is changed to a electrical energy

Answer:

its getting colder

Explanation:

Answer:

All of the energy from the Sun that reaches the Earth arrives as solar radiation, part of a large collection of energy called the electromagnetic radiation spectrum. Solar radiation includes visible light, ultraviolet light, infrared, radio waves, X-rays, and gamma rays. Radiation is one way to transfer heat.

Answer:

3

Explanation:

pH+pOH=14

Answer:

Explanation: The goal of every country should be to produce more materials and goods

Answer:

hi.

Explanation:

1. B

2. C

3. A

4. B

5.B

hope this helps