The forensic technician at a crime scene has just prepared a luminol stock solution by adding 10.0 g of luminol into a total volume of 75.0 mL of H2O .What is the molarity of the stock solution of luminol?Express your answer with the appropriate units.

ANSWER

EXPLANATION

So, the number of particles in a mole is about 80,000 the number of grains of sand on Earth’s beaches.

How to slove and Compare the value you calculated for the number of sand grains on Earth's beaches to the number of particles In mole?

Using sand grains that take up space of 1 mm, when these sand grains are laid side by side, there are about 1000 grains of sand per m, 1000000 per square m and 1000 × 1000 × 1000 per cubic m.

That is 10⁹ grains of sand per cubic meter.

An average beach has sand volume of (1.875 × 10⁷) cubic metres

There are over 400 beaches in the world, Using an estimate of 400 beaches

The number of grains of sand on Earth's beaches = 10⁹ × 400 × 1.875 × 10⁷

There are approximately (7.5 × 10¹⁸) grains of sand on all of the world's beaches

Then, Avogadro's number found that 1 mole of all particles contain

(6.022 × 10²³) particles.

So, the number of particles in a mole is about [(6.022 × 10²³)/(7.5 × 10¹⁸)]

the number of grains of sand on Earth’s beaches.

So, the division gives, (8.0 × 10⁴).

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Answer:

dt=20.08

Explanation:

Q=msdt

840=10*4.184*dt

dt=840/(10*4.184)

dt=20.08

When you reach into the oven to take out the cookies, the thermal energy from your hand transfers to the cookies. The cookies become hot while your hand becomes cooler.

What is thermal energy?
Thermal energy is the energy contained within a system that controls its temperature. The flow of thermal energy is defined as heat. Thermodynamics is a branch of physics that deals with how heat is transferred between different systems and how work is done in the process (see the first law of thermodynamics).

We are usually interested in the role of thermal energy in ensuring energy conservation in the context of mechanics problems. Almost every transfer of energy in real-world physical systems occurs with less than 100% efficiency and results in some thermal energy. Typically, this energy takes the form of low-level thermal energy.

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Answer

2319.698 g

Procedure

Use the Avogadro's number and then the molecular weight to convert into grams. The formula for aluminum bromide is AlBr₃.

Answer

a. True

Explanation

If there was nothing to avoid from objects pulling towards one another many results may happen.

The formula weight of zinc phosphate is 385g/mol.

The formula weight or molar mass of zinc phosphate is calculated by adding weight of every single element present in zinc phosphate.

Formula of zinc phosphate is Zn₃(PO₄)₂.

Weight of 3 zinc atoms = 3×65= 195g/mol

Weight of 2 phosphorus atoms =2×31=62g/mol

Weight of 8 oxygen atoms = 8×16= 128g/mol

So, the total molecular weight of the compound is 195+62+128= 385g/mol.

Thus, the molecular weight of zinc phosphate is 385g/mol.

Zinc phosphate is an inorganic chemical substance that is used as a priming pigment or as part of the electroplating process to provide a corrosion-resistant coating on metal surfaces. It is common practice to employ a seeding chemical as a pre-treatment because zinc phosphate adheres to crystalline structures better than bare metal. Dental practices use zinc phosphate, which is created from zinc phosphate cement.

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1) The rate constant is  9.22 * 10^-5 s-1

2) The time taken is 15033 s

3) The initial concertation  is  9.22 * 10^-5 M

We can define the rate of reaction as the rate at which reactants are converted into products or the rate of which reactants disappear and the products appear in a given reaction.

We are told that in this reaction as we can see, the initial concentration decrease at 25% in t =52 min.

Initial concentration [A]o =  [A]o

Final concentration =  [A]o - 0.25  [A]o = 0.75 [A]o

Time taken = 52 min or 3120 s

We have that;

ln[A] = -kt + ln[A]0

k = -(ln[A] -  ln[A]0)/t

k = - (ln0.75 [A]o/A]0)/3120

k = 9.22 * 10^-5 s-1

b)

Given that

[A] =  [A]o - 0.75  [A]o = 0.25 [A]o

ln[A] = -kt + ln[A]0

t = -(ln[A] -  ln[A]0)/k

t = - (ln0.25 [A]o/A]0)/9.22 * 10^-5

t = 15033 s

c) When the rate is 2.5 mol/L·s

k = - (ln0.25 (2.5)/ln(2.5))/15033

k = 9.22 * 10^-5 M

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Volume of the balloon at 2.00 × 10⁴ m is 1.52x10³ L

Volume is the three dimensional qualities that is used to measure capacity of solid shape and atmospheric pressure is the air around you has weight and it weighs down everything it touches is called atmospheric pressure

Here given data is

Pi = 1.0 atmosphere = absolute atmospheric pressure

P f = 61.0 mm Hg = atmospheric pressure

= 61.0/760 atmosphere

=  0.0802 atmosphere

Vi =  171 L

T i = 20.0°C = 20+273 = 293 K

T f = 210 K

We have to find volume of the balloon at 2.00 ×10⁴ m =?

Then the formula is

Pi × Vi/T i = P f × V f/T f

1 atm×171 L/293 K = 0.0802× V f/210K

V f = 1.52x10³ L

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Explanation:

According to the problem, hydrochloric acid will react with oxygen gas to produce water and chlorine gas.

hydrochloric acid + oxygen gas ----> water + chlorine gas

The balanced equation will be:

4 HCl + O₂ -----> 2 H₂O + 2 Cl₂

If we pay attention to the coefficients of the reaction we will see that 4 moles of HCl will react with 1 mol of O₂ to produce 2 moles of H₂O and 2 moles of Cl₂. So, 1 mol of O₂ will produce 2 moles of H₂O. The molar ratio between O₂ and H₂O is 1 to 2.

1 mol of O₂ : 2 moles of H₂O molar ratio

We can use this relationship to find the number of moles of H₂O that are produced from 5.52 moles of O₂.

moles of H₂O = 5.52 moles of O₂ * 2 moles of H₂O/(1 mol of O₂)

moles of H₂O = 11.0 moles

Answer: 11.0 moles of water are produced from 5.52 moles of oxygen gas.

If air conditioning system won't be able to chill your home until the fan is fixed if it has stopped functioning.

Your air conditioning system won't be able to chill your home until the fan is fixed if it has stopped functioning. The circuit breaker should be checked first if the AC unit fan is not whirling. Check to see if the circuit breaker for the air conditioning equipment has tripped. The heat from the motor and the weather outdoors can cause a circuit breaker to trip due to overheating.

If the fan won't turn on, the fan motor might be malfunctioning. If you are having trouble getting the blades to turn, the motor bearings may be dusty or stuck, or there may be debris wrapped around the fan axle.

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If the fan motor is malfunctioning, it could seriously harm your system. Your entire system could fail if the fan motor becomes stuck, which could lead to the compressor overheating and failing.

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1. The concentration of the vitamin C in ppm is 800 ppm

2. The concentration of the vitamin C in ppb is 800000 ppb

1. How to determin the concentration in ppm

The concentration of the vitamin C in ppm can be obtained as follow:

Concentration (in ppm) = (mass of solute / mass of solution) × 10⁶

Concentration (in ppm) = (0.12 / 150) × 10⁶

Concentration (in ppm) = 800 ppm

2. How to determin the concentration in ppb

The concentration of the vitamin C in ppb can be obtained as follow:

Concentration (in ppb) = (mass of solute / mass of solution) × 10⁹

Concentration (in ppb) = (0.12 / 150) × 10⁹

Concentration (in ppb) = 800000 ppb

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We have an initial concentration of a stock solution that has molarity equal to 1M. In a previous question, the stock solution was diluted 10 times, this solution was called solution A. The concentration of solution A found was equal to 0.1M.

Now, we are asked to find the concentration of solution B that starts from solution A.

The initial concentration C1 is the concentration of solution A, equal to 0.1M. The initial volume (V1) is 10mL, and the final volume (V2) is 100mL. We will apply the dilution equation that says:

We clear C2 and replace the known data:

Answer: The molarity of solution B is 0.01 M

The student's approximate percent deviation or percentage of error in the measurement of the mass of the sample is 9.38 %.

Percent deviation is calculated to determine the accuracy of data collected during an experiment by comparing it to the theoretical results. Percent deviation is commonly used to check for data errors in student experiments.

Percent deviation can be referred to how much measured data differs from a known or theoretical value. A negative percent deviation indicates that the measured data is lower than the theoretical value. A positive percent deviation shows that the measured value is higher.

Given the actual value of the mass = 16 g

The calculated or approx value by student = 17.5 g

The percentage deviation = [(Approx - actual)/ actual ] × 100

                                              = [(17.5 - 16)/16] × 100

               Percentage error  = 9.38 %

Therefore, the student's approximate percent deviation is 9.38 %.

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INFORMATION:

We know that:

- 34.37 g of tin(IV) phosphate is added to 34.05 g of sodium carbonate

- 24.24 g of tin(IV) carbonate are made

And we must find the %yield

STEP BY STEP EXPLANATION:

Balanced equation:

Sn3(PO4)4 + 6Na2CO3 → 3Sn(CO3)2 + 4Na3PO4

1. We must find the amount of tin carbonate produced by tin phosphate

2. We must find the amount of tin carbonate produced by sodium carbonate

3. We must find the theoretical amount of tin carbonate produced

Since sodium carbonate is the limiting reactant, then the theoretical amount of tin carbonate produced would be

4. Finally, the %yield would be

ANSWER:

1.

2.

3.

4.

The relative atomic mass of the given elements are:

The relative atomic mass of an element can be defined as the number of times the average atomic mass of the element is heavier than one-twelfth the mass of an atom of carbon-12.

The relative atomic mass of an element is obtained by summing the product of the mass of each isotope of an element and its relative abundance.

The relative atomic mass of the elements are determined as follows:

Sulfur:

Relative atomic mass = (32.95 * 0.0075) + (31.972 * 0.950) + (33.967 * 0.042) + (36.01435 * 0.0002)

The relative atomic mass of sulfur = 32.054 amu

Chlorine:

Relative atomic mass =  (34.97 * 0.755) + (36.97 * 0.245)

The relative atomic mass of chlorine = 35.46

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Answer:

0.585 moles Na₂SO₄

Explanation:

To find the amount of moles of Na₂SO₄, you need to multiply the given mass (grams) by the molar mass. You can use the molar mass to convert between grams and moles because the molar mass exists as a ratio which compares the mass of Na₂SO₄ per every 1 mole. The ratio should be arranged in a way that allows for the cancellation of units (grams should be in the denominator). The final answer should have 3 sig figs like the given value.

Atomic Mass (Na): 22.990 g/mol

Atomic Mass (S): 32.065 g/mol

Atomic Mass (O): 15.999 g/mol)

Molar Mass (Na₂SO₄): 2(22.990 g/mol) + 32.065 g/mol + 4(15.999 g/mol)

Molar Mass (Na₂SO₄): 142.041 g/mol

 83.1 grams Na₂SO₄                  1 mole
--------------------------------  x  --------------------------  =  0.585 moles Na₂SO₄
                                             142.041 grams

The reaction type which gives one product is a combination reaction.

What is a combination reaction?

Combination reactions are those in which two or more chemical entities join together to form a single product.

Generally, all the other types mentioned in the question can give single products under different circumstances but a combination reaction always gives a single product as shown in the above reaction.

4Fe  + 3O2  =  2Fe2O3

Hence, the answer is a combination reaction.

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The hybrid orbital of this molecule is B. sp³d

Trigonal symmetry was used to generate a combination of s and p orbitals, which are kept at 1200. Ethylene (C2H4) sp3 hybridization is an example of sp2 hybridization. To create a novel hybrid orbital known as the sp3 sp3 orbital, one's' orbital and three 'p' orbitals of equal energy are mixed in this type: One of four new comparable orbitals that result from geometrically combining one s orbital and three p orbitals to create a normal tetrahedron's four corners.

Again, we refer to them as sp3 particles because they are made up of a single s orbital and three p orbitals. These degenerate hybrid orbitals are created to offset the s-p transition's energy upward.

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In essence, there is no chemical reaction between ammonia and water. Although it is frequently said to produce NH₄OH, the overall response is:

H₂O + NH₃ = NH₄⁺ + OH⁻

You might compare the acid strength of H₂O (pka 15.7) and NH4⁺ (pka 9.24) or the base strength of NH₃ and OH⁻ to see which way the reaction would proceed. The reaction would shift to the weaker acid (H₂O) or the weak base in either case (NH₃). Despite what the bottle claims, weak doesn't make strong. I mean, there might be a small amount of NH₄⁺ and OH⁻ in the air, but not much.

The iron (III) ion forms an insoluble hydroxide and precipitates out of solution when ammonia is added to the solution.

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Step 1

The equations used here:

------------

Step 2

Information provided:

[H3O+] = 3.5×10^−7 M

------------

Step 3

Procedure:

Firstly, from (1):

pH = -log [H3O+]

pH = -log (3.5×10^−7 M) = 6.5

----

From (3):

pH + pOH = 14

pOH = 14 - pH

pOH = 14 - 6.5

pOH = 7.5

----

From (2)

pOH = - log [OH-] => [OH-] = 10^-(pOH)

[OH-] = 10^-(pOH) = 10^-(7.5) = 3.2x10^-8 M

Answer: [OH-] = 3.2x10^-8 M

Answer:

If the temperature of a gas remains constant the the pressure of gas will increase the impacts on the walls of the container , thus increasing the volume

In order to reliably compute the number of moles present from the measured weight and the known molar mass, is a chemical that can be exactly weighed out in pure forms, such as oxalic acid.

A standard solution is a liquid with a precisely known concentration that is made from a primary standard, which is a substance that is stable, highly pure, highly soluble in water, and has a high molar mass to enable precise weighing. The primary standard is weighed precisely and is made up to a specific volume.

The terms primary solution and secondary solution refer to two different categories of standard solutions. A primary standard solution is a highly pure, low-reactive solution. A secondary standard is less pure than a prime standard and more chemically reactive.

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Answer:

I think you have to calculate the oxidation number of each atom in the reaction.

Explanation:

Hope that helped! ^u^

The wind tends to blow from over the water to over the land due to the differences in the density of air. Air over the water is cooler than air over the land and denser air from over the water flows toward the land. Therefore, options A, C, and D are correct.

The sea breeze is the wind that blows across the sea toward land throughout a sunny day. The air over land heats up more quickly during the day and starts to rise in coastal areas.

A low-pressure area forms on the surface of the land as the warm air rises, allowing air over the water to enter. As a result, during the day the wind direction is from the water to the land and this wind happens to be the sea breeze.

The sea breeze is a thermally produced wind during the day blowing from the cool ocean towards warm land. It is caused by the difference in the density of air between the land and the ocean.

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According to the definition of acids, for Bronsted-Lowry, an acid is any species that can donate a proton, which is H+, to another molecule, and a base is any species that is capable of accepting a proton. Therefore, according to this definition, we have the following reaction:

H2Y- + H2Z- <---> H3Y + HZ^2-

In this reaction, we can see that H2Z donated a H+ to H2Y, therefore H2Z is the acid on the reactants side, and H2Y will be the base.

On the products side, since we have a reversible reaction, H3Y will donate a H to HZ^-2, therefore H3Y will be the acid, and HZ^-2 will be the base

Answer:

1.80 g (grams) of glucose.

Explanation:

First, we dissolve 20.0 g of glucose in a volume of water of 100 mL (0.1 L), so let's calculate the concentration of glucose in g/L, like this:

Now, we take 45 mL (0.045 L) of this solution that contains a concentration of glucose of 200 g/L to create a new solution with 0.500 L.

From this new solution, we have to find the mass of glucose if we took 100 mL (0.1 L) of this solution, so we have to use the following equation:

Where C is concentration, V is volume, and subindex 1 and 2 indicate the initial solution, which in this case, is C1 = 200 g/L, V1 = 0.045 L, and the final solution with unknown concentration (C2) and a volume of V2 = 0.500 L.

Let's solve for C2 and replace the given data to obtain the new concentration (final concentration) of the new solution of 0.500 L, like this:

The final concentration of glucose in 0.500 L would be 18.0 g/L.

The next and final step is to calculate the total mass using the volume that we took from the 0.500 L solution, which is 100.0 mL (0.1 L). To do this, we have to do a dimensional analysis to obtain the answer in units of grams, so the calculation will look like this:

The answer would be that we have 1.80 g (grams) of glucose in 100 mL from the 0.500 L solution.

Explanation:

Formaldeyde

Lewis Structure:

Structural diagram:

3D diagram.