8. What was the original concentration in the BHL sample, if the dilution is 1:500 and the concentration 0.07 mg/ml

Answer:

[tex]\boxed {\boxed {\sf 0.255 \ mol \ C }}[/tex]

Explanation:

If we want to convert from grams to moles, the molar mass is used. This is the mass of 1 mole. They are found on the Periodic Table as the atomic masses, but the units are grams per mole (g/mol) instead of atomic mass units (amu).

Look up the molar mass of carbon.

Set up a ratio using the molar mass.

[tex]\frac {12.011 \ g \ C}{ 1 \ mol \ C}[/tex]

Since we are converting 3.06 grams to moles, we multiply by that value.

[tex]3.06 \ g \ C*\frac {12.011 \ g \ C}{ 1 \ mol \ C}[/tex]

Flip the ratio. This way, the ratio is still equivalent, but the units of grams of carbon cancel.

[tex]3.06 \ g \ C* \frac{1 \ mol \ C}{12.011 \ g\ C}[/tex]                      

[tex]3.06 * \frac{1 \ mol \ C}{12.011 }[/tex]    

[tex]\frac {3.06}{12.011 } \ mol \ C[/tex]                                

[tex]0.25476646 \ mol \ C[/tex]

The original measurement of grams (3.06) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

The 7 in the ten-thousandth place tells us to round the 4 up to a 5.

[tex]0.255 \ mol \ C[/tex]

3.06 grams of carbon is approximately 0.255 moles of carbon.

Answer:

At the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced

Explanation:

At cathode, reduction reaction takes place.

The dissociation of MgI2 in aqueous solution is Mg2+(aq) and 2I−(aq)

Here, the Iodine reduces to 2I−(aq) from state of 0 (MgI2) to state of -1 (2I−(aq))

Hence, at the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced

Answer:

During electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced at the cathode

Explanation:

Electrolysis is a process whereby ionic compound is broken down or degraded into smaller substances when electric current flow through it.

During electrolysis of magnesium iodide, At the cathode reduction reaction occur .

MgI2 is dissociated to is Mg2+(aq) and 2I−(aq)

Then Iodine is reduced to 2I−(aq) which is 0 in (MgI2) then change to -1 (2I−(aq))

Therefore;

During electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced at the cathode.

Answer:

Molarity = 0.809 M

mole fraction = 0.047

Explanation:

The complete question is

Calculate the molarity and mole fraction of acetone in a 1.09-molal solution of acetone (CH3COCH3) in ethanol (C2H5OH). (Density of acetone = 0.788 g/cm3; density of ethanol = 0.789 g/cm3.) Assume that the volumes of acetone and ethanol add.

Solution -

Solution for molarity:

1.09-molal means 1.09 moles of acetone in 1.00 kilogram of ethanol.

1)  

Mass of 1.09 mole of acetone

= 1.09  mol x 58.0794 g/mol = 63.306 g

Density of acetone = 0.788 g/cm3  

Thus, volume of 1.09 moles of acetone = 63.306 g/0.788 g/cm3 = 80.34 cm3

For ethanol

1000 g divided by 0.789 g/cm3 = 1267.427 cm3

Total volume of the solution = Volume of acetone + Volume of ethanol = 80.34 cm3 + 1267.427 cm3 = 1347.765 cm3  = 1.347 L

a) Molarity:

1.09 mol / 1.347 L = 0.809 M

Mole Fraction  

a) moles of ethanol:

1000 g / 46.0684 g/mol = 21.71 mol

b) moles of acetone:

1.09 / (1.09 + 21.71) = 0.047

Answer:100

Explanation:

the equation is not present.

Answer:

B. Dividing the number by 1,000

Explanation:

Every time you move the decimal ,add a zero.Since the decimal is moved three times ,there are three zeroes. When you move left ,the number is getting smaller so it is division.

Answer: Electrons are taken up by [tex]PbO_2[/tex] and they are lost by [tex]HCl[/tex]

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously. It is also called the reaction where the exchange of electrons takes place.

An oxidation reaction is defined as the reaction in which a chemical species loses electrons takes place. In this reaction, the oxidation state of a substance gets increased.

A reduction reaction is defined as the reaction in which a chemical species gains electrons takes place. In this reaction, the oxidation state of a substance gets reduced.

For the given chemical reaction:

[tex]PbO_2+4HCl\rightarrow PbCl_2+Cl_2+2H_2O[/tex]

The half-reactions for this redox rection follows:

Oxidation half-reaction:  [tex]2HCl\rightarrow ClO_2 + 2e^-[/tex]

Reduction half-reaction:  [tex]PbO_2+2e^-\rightarrow PbCl_2[/tex]

Hence, electrons are taken up by [tex]PbO_2[/tex] and they are lost by [tex]HCl[/tex]

Answer:

Its D  

Explanation:

Did it on edge

According to the reaction: H₂S0₄ + Ca(OH)₂ → CaSO₄+ 2H₂O, the base is Ca(OH)₂.

Base is defined as a substance which can accept protons or any chemical compound that yields hydroxide ions (OH-) in solution.

Generally, base are substances that produces hydroxide ion when dissolve in water.  

Base are substances that reacts with acid to produce salt and water. Example of base includes sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide etc.

Therefore, according to the reaction:

H₂S0₄ + Ca(OH)₂ → CaSO₄+ 2H₂O

The base is Ca(OH)₂.

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Answer:

Option A. The specific heat is 0.897 J/gºC, The Substance is aluminum.

Explanation:

We'll begin by calculating the change in temperature of the substance. This can be obtained as follow:

Initial temperature (T₁) = 20.0 °C

Final temperature (T₂) = 40.0 °C

Change in temperature (ΔT) =?

ΔT = T₂ – T₁

ΔT = 40 – 20

ΔT = 20 °C

Finally, we shall determine the specific heat capacity of the substance. This can be obtained as follow:

Mass (M) = 136 g

Change in temperature (ΔT) = 20 °C

Heat (Q) absorbed = 2440 J

Specific heat capacity (C) =?

Q = MCΔT

2440 = 136 × C × 20

2440 = 2720 × C

Divide both side by 2720

C = 2440 / 2720

C = 0.897 J/gºC

Comparing the specific heat capacity (i.e 0.897 J/gºC) of the substance with those in the table above, the substance is Aluminum.

Thus, option A gives the correct answer to the question.

Answer:

0.960 mol of Ag

Explanation:

Mg(s) + 2AgNO3(aq) → Mg(NO3)2(aq) + 2Ag(s)

1.00 mol of Mg ---- 2.00 mol of Ag

0.480 mol of Mg ---- x

x = (0.480×2)/1 = 0.960 mol of Ag

Answer:

The answer is C

Explanation:

The more space the molecules have the faster they will move, solid doesn't allow movement at all, when it gets to liquid they are free to move around because it's more space, when a gas they can move all around in the air.

Answer:

The amount after three year is 617934.1302

Explanation:

Complete question

A person places $530,000 in an investment account earning an annual rate of 5.25%, compounded continuously. Using the formula V = Pe^{rt}V=Pe rt , where V is the value of the account in t years, P is the principal initially invested, e is the base of a natural logarithm, and r is the rate of interest, determine the amount of money, to the nearest cent, in the account after 3 years

Solution

The formula for calculating compound interest is

[tex]A = p (1 + \frac{r}{n})^{nt}[/tex]

Substituting the given values we get -

[tex]A = 530,000 (1 + \frac{5.25}{100})^3\\A = 530,000 * ( 1+ 0.0525)^3\\A = 530,000 * ( 1.0525)^3\\A = 617934.1302[/tex]

The amount after three year is 617934.1302

Answer: There are [tex]16.14 \times 10^{23}[/tex] atoms of hydrogen are present in 40g of urea, [tex](NH_{2})_{2}CO[/tex].

Explanation:

Given: Mass of urea = 40 g

Number of moles is the mass of substance divided by its molar mass.

First, moles of urea (molar mass = 60 g/mol) are calculated as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{40 g}{60 g/mol}\\= 0.67 mol[/tex]

According to the mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] atoms.

So, the number of atoms present in 0.67 moles are as follows.

[tex]0.67 mol \times 6.022 \times 10^{23} atoms/mol\\= 4.035 \times 10^{23} atoms[/tex]

In a molecule of urea there are 4 hydrogen atoms. Hence, number of hydrogen atoms present in 40 g of urea is as follows.

[tex]4 \times 4.035 \times 10^{23} atoms\\= 16.14 \times 10^{23} atoms[/tex]

Thus, we can conclude that there are [tex]16.14 \times 10^{23}[/tex] atoms of hydrogen are present in 40g of urea, [tex](NH_{2})_{2}CO[/tex].

Answer:

molecules take up more space

To solve this we must be knowing each and every concept related to  chemical formula. Therefore, in the above given ways the chemical formula for the molecule can be written.

A chemical formula is a scientific notation that uses atomic symbol and numerical subscripts to represent the number and types of elements contained in a molecule. A chemical formula seems to be a concise written description of an existing three-dimensional molecule.

A chemical formula characterizes a material to the atomic level. There are three sorts of chemical formulas: empirical, molecular, and structural.

The chemical formula for the given molecules are:

2. H[tex]_2[/tex]O

3. O[tex]_3[/tex]

4. H[tex]_2[/tex]

5. CO[tex]_2[/tex]

6. CO

7. NO[tex]_2[/tex]

8. CH[tex]_4[/tex]

Therefore, in the above given ways the chemical formula for the molecule can be written.

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Answer:

1.3 × 10² g

Explanation:

Step 1: Given data

Moles of oxygen: 4.0 mol

Step 2: Calculate the mass corresponding to 4.0 moles of oxygen

For a given chemical reaction, we need 4.0 moles of oxygen and we want to find what mass in grams it represents. To convert moles to mass, we need a conversion factor: the molar mass. The molar mass of oxygen is 32.00 g/mol.

4.0 mol × 32.00 g/mol = 1.3 × 10² g

Answer:

Explanation:

A chemical bond formed when two atoms share three pairs of electrons is a triple bond; it is best described as covalent.

Answer: look at the explanation and try to work it

Explanation: in contrast, our atmosphere blocks most ultraviolet light (UV) and all X-rays and gamma-rays from reaching the surface of Earth. Because of this, astronomers can only study these kinds of light using detectors mounted on weather balloons, in rockets, or in Earth-orbiting satellites.

Answer: D it’s is 2.0 s

i think..

Explanation:

Answer:

In order from left to right, 7 (gamma), 5 (ultraviolet, now continue pattern), 4, 6, 2, 3, 1.

Answer: False

Explanation:

Hope this help

Answer:

True.

Explanation:

Every child will contain the same number of chromosomes as the parents (otherwise they wouldn't be considered the same species). Additionally, animals can only mate with a species containing the same number of chromosomes as themselves. This means if the offspring of the parents had a different number fo chromosomes the offspring would be unable to mate with animals of it's own species.

Answer:

I think it is 7.60 X 1

but if it's not srry

Answer:

The heat capacity of the metal underneath the gold is 0.431 J/g°C

Explanation:

Using the formula as outlined in the image:

Q = m × c × ∆T

Where;

Q = amount of heat energy (J)

m = mass of substance (g)

c = specific heat capacity (J/g°C)

∆T = change in temperature (°C)

According to the information in this question;

Q = 503.9J

m = 23.02g

c = ?

∆T = 74°C - 23.2°C = 50.8°C

Using Q = m × c × ∆T

c = Q ÷ m∆T

c = 503.9 ÷ (23.02 × 50.8)

c = 503.9 ÷ 1169.42

c = 0.431 J/g°C

From the above heat capacity of the metal underneath the gold, it is obvious that the metal is not pure gold (c = 0.129J/g°C)

Answer:

Number of moles  of sodium dissolved =  6.0 *10^23

Explanation:

The image for the question is attached

Solution

a) Total 181 ions of Na are dissolved

b)

The number of moles of sodium dissolved = 181/6.023 *10^23

Number of moles  of sodium dissolved = 5.987 * 10^23

Number of moles  of sodium dissolved =  6.0 *10^23

The given question is incomplete, the complete question is:

A chemist must dilute 54.1 mL of 20.2 M aqueous silver perchlorate (AgC102) solution until the concentration falls to 3.00 M. He'll do this by adding distilled water to the solution until it reaches a certain final volume. Calculate this final volume, in liters. Round your answer to 3 significant digits.

Answer:

The correct answer is 0.364 L.

Explanation:

A solution is made less concentrated by diluting it with a solvent. There is no change in the number of moles when more solvent is added to the solution. In case, if the solution is diluted from V1 to V2, a change is noticed in the molarity of the solution based on the given equation,

M1V1 = M2V2

In the given case, the V1 or the volume of the original solution is 54.1 ml, M1 or the molarity of the original solution is 20.2 M.

The M2 or the molarity of the diluted solution is 3.00 M, there is a need to find the V2 or the volume of the diluted solution.

Now by putting the values in the equation we get,

= 20.2M * 54.1 ml = 3.0 M * V2

V2 = 364.27 ml

It is known that 1000 ml is equivalent to 1L, therefore, 1 ml = 0.001 L

Now, the value of V2 will be,

= 364.27 * 0.001 L = 0.36427 L or 0.364 L

Answer:

I think it's 1.D

2.C

3.C

my apologies if it's incorrect

Answer:

10.65 moles

Explanation:

O2:H2O

8:6

14.2:x

x= 10.65 moles

Answer: Type A are cardiac muscles Type B are skeletal muscles, and Type C are smooth muscles.

Explanation: sub to technoblade :P

Answer:

B. Most energy comes from non-renewable sources

Explanation:

A P E X

In United States Most energy comes from non-renewable energy sources, as petroleum  coal and others has the highest consumption in the given chart

In the given chart, the energy consumption in US is based on Petroleum, coal and others  the highest consumption pattern as compared to other energy sources

Hence, most energy in the US is from non-renewable energy sources

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