An unlit match contains approximately 1,000 J of chemical energy. When it burns, the match releases thermal energy and light energy. After it has burned, the remaining match contains 250 J of chemical energy. If the thermal energy was measured to be 400 J, how much light energy did the match emit?

Answer:

The volume of first and second compound are 9.15 ml and 10.85 ml.

Explanation:

Given that,

Density of graphite = 2.25 g/cm³

Volume of mixture = 20.0 mL

Density of first compound = 1.492 g/ml

Density of second compound = 2.890 g/ml

Let the volume of first mixture = x

The volume of second mixture = (20-x)....(I)

We need to calculate the volume of first compound

Using formula of  density of mixture

[tex]\rho=\dfrac{V_{1}\rho_{1}+V_{2}\rho_{2}}{V_{1}+V_{2}}[/tex]

Where, [tex]V_{1}[/tex] = volume of first compound

[tex]V_{2}[/tex] = volume of second compound

[tex]\rho_{1}[/tex] =density of first compound

[tex]\rho_{1}[/tex] = density of first compound

Put the volume into the formula

[tex]2.25=\dfrac{x\times1.492+(20-x)\times2.890}{x+20-x}[/tex]

[tex]45=1.492x+57.8-2.890x[/tex]

[tex]45-57.8=1.492x-2.890x[/tex]

[tex]12.8=1.398x[/tex]

[tex]x=\dfrac{12.8}{1.398}[/tex]

[tex]x=9.15\ ml[/tex]

We need to calculate the volume of second compound

Using equation (I)

[tex]V_{2}=20-x[/tex]

Put the value of x

[tex]V_{2}=20-9.15[/tex]

[tex]V_{2}=10.85\ ml[/tex]

Hence, The volume of first and second compound are 9.15 ml and 10.85 ml.

Answer:

Pb(NO₂)₂(aq) + 2 LiCl(aq) ⇒ PbCl₂(s) + 2 LiNO₂(aq)

Explanation:

Let's consider the reaction between aqueous lead (II) nitrite and aqueous lithium chloride to form solid lead (II) chloride and aqueous lithium nitrite.

Pb(NO₂)₂(aq) + LiCl(aq) ⇒ PbCl₂(s) + LiNO₂(aq)

This is a double displacement reaction. We will start balancing Cl by multiplying LiCl by 2.

Pb(NO₂)₂(aq) + 2 LiCl(aq) ⇒ PbCl₂(s) + LiNO₂(aq)

Now, we have to balance Li by multiplying LiNO₂ by 2.

Pb(NO₂)₂(aq) + 2 LiCl(aq) ⇒ PbCl₂(s) + 2 LiNO₂(aq)

The equation is now balanced.

The balanced chemical reaction equation required is; Pb(NO2)2(aq) + 2 LiCl(aq) -----> PbCl2(s) + 2LiNO2(aq)

In order to write a balanced chemical reaction equation, we must write down the symbols of the compounds involved as follows;

lead (II) nitrite  - Pb(NO2)2

lithium chloride - LiCl

lead (II) chloride - PbCl2

lithium nitrite - LiNO2

Recall that the principle of writing a balanced chemical reaction equation is that the number of atoms of each element on both sides of the reaction equation must be the same. The required balanced chemical reaction equation is;

Pb(NO2)2(aq) + 2 LiCl(aq) -----> PbCl2(s) + 2LiNO2(aq)

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Answer:

The correct answer is "Pro; P".

Explanation:

Amino acids are not only identified by its full name, there are three-letter and one-letter abbreviations for each amino acid that helps to annotate sequences and biological processes. In the case of proline, the three letter abbreviation is "Pro" and the one letter abbreviation is "P". Proline got its name for its cyclic structure, that resembles the structure of pyrrole.

Answer:

L=7.0125*10^-5

Explanation:

LET  

 Length of polyethene chain= L

Molecular weight OF polyethene= MW

Molecular weight of monomer =mw

Monomer length= l

L=(MW/mw) *l

              L= (28.05g/mol10^6gmol-1) * 2.5

             L=70.125*10^-6

            L=7.0125*10^-5

Hence, the length will be L=7.0125*10^-5 .

Answer:

diamond

sugar

rubber

salt (NaCl)

wood

ice

flour

Answer:

diamond

sugar

salt

ice

Explanation:

Answer:

It is a chemical change

Explanation:

the reason is because the will not be able to materialize back into it's original form.

Answer:

It will take the police car 3.5 hours to travel a distance of 175 miles traveling at a rate of 50 miles/hour.

Explanation:

If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.

Answer: 2.7 cm

Explanation: ~~~~~ there ya go

Answer:

[tex]d=1x10^{-9}dm[/tex]

Explanation:

Hello,

In this case, considering that 1 m equals 10 dm, the required diameter of the atom in decimetres is:

[tex]d=1x10^{-10}m*\frac{10dm}{1m} \\\\d=1x10^{-9}dm[/tex]

Best regards.

Answer:

[tex]\rho =8.50g/cm^3[/tex]

Explanation:

Hello,

In this case, due to the volume difference caused by the addition of the metal, one could notice that the volume of the metal is:

[tex]V_{metal}=9.84cm^3-6.85cm^3=2.99cm^3[/tex]

In such a way, given the mathematical definition of density, it turns out:

[tex]\rho =\frac{m}{V}=\frac{25.4253g}{2.99cm^3}\\\\\rho =8.50g/cm^3[/tex]

Regards.

Answer:

b. Magnetism (sorry im very late)

Explanation:

Intensive properties do not depend on size, no matter what it doesn't. For example, magnetism, density, melting and boiling points, and color. All of those support intensive property.

Intensive properties are physical properties that do not depend on the amount or size of the material being measured. In other words, they remain constant regardless of the quantity of the substance.

The correct answer is b. magnetism.

Out of the options provided:

a. mass is an extensive property because it depends on the amount of the substance. If you have more of a substance, you will have a greater mass.

b. magnetism is an intensive property because it remains the same regardless of the size or amount of the material with the magnetic property.

c. shape is not a standard property used to classify intensive or extensive properties. It is more of a description of the object's form.

d. volume is an extensive property because it depends on the size and amount of the substance. If you have more of a substance, you will have a larger volume.

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Answer:

1. 0.209quart

2. 743.6pounds

3. 22500kg/m^3

4. 2.07pounds

5. 4.50cm

Explanation:

Note that, these questions are related to density which can be calculated using the formula:

Density (p) = Mass (m) / Volume (v)

However, the units are different for each questions, hence, must be made the same

1. 1 ounce = 28.35 grams

95 ounces will be 95 × 28.35 = 2693.2g

Volume = mass/density

Volume of Mercury= 2693.2/13.6

Volume= 198ml

1 ml = 0.00106quart

198ml = 198 × 0.00106 = 0.209quart

2. 1 gallon = 3785.4ml

55 gallons = 55× 3785.4 = 208197ml

Mass = density × volume

Mass = 1.62 × 208197

Mass = 337,279.14g

1 pounds = 453.592 g

337279.14 g = 337279.14/453.592

Mass = 743.6pounds

3. 1g/cm^3 = 1000kg/m^3

Hence, a density of 22.5g/cm^3 will be 22.5 × 1000 = 22500kg/m^3

4. Volume of a cube of side 5cm each will be 5×5×5 = 125cm^3

Density = 7.50g/cm^3

Mass = Density×volume

Mass in grams = 7.50 × 125

Mass = 937.5grams

1 pound = 453.592 g

Therefore, 937.5g will be 937.5/453.592 = 2.07pounds.

5. Volume = Mass / density

Volume = 500/10.5

Volume = 47.62cm^3

Since a ball is spherical in shape, volume of a sphere (V) = 4/3πr^3

To find radius, we say;

47.62 = 1.33 × 3.142 × r^3

47.62 = 4.179 × r^3

r^3 = 47.62/4.179

r^3 = 11.395

r = 3√11.395

r = 2.25cm

To get diameter (d), we multiply the radius (r) by 2,

d = 2 × 2.25

d= 4.50cm

Answer:

The atoms of an element are represented in a chemical line drawing with its chemical formula.

Explanation:

chemical structural drawing helps to represent the pattern for which an element is formed. Chemical elements are made up of atoms that represent their single state.

The line drawing is made up of lines (representing the chemical bond between atoms) and the atoms or various atoms that make up the element.

Answer:its a law

Explanation:

I passed that quiz 100%, my answer for that question was law

so its law

Answer: Carbon, because it is in group 14 and has four valence electrons

Explanation: Just did this quiz

Answer:carbon

Explanation:

Answer:

atomic number of fluorine

is 9

Answer:

0.307 g

Explanation:

Step 1: Given data

Volume of solution: 100.0 mL

Molarity of the NaCl solution: 0.0525 M

Molar mass of NaCl: 58.44 g/mol

Step 2: Calculate the moles of NaCl required

The molarity is equal to the moles of solute (NaCl) divided by the liters of solution.

M = moles of NaCl / liters of solution

moles of NaCl = M × liters of solution

moles of NaCl = 0.0525 mol/L × 0.1000 L = 5.25 × 10⁻³ mol

Step 3: Calculate the mass corresponding to 5.25 × 10⁻³ moles of NaCl

5.25 × 10⁻³ mol × 58.44 g/mol = 0.307 g

Answer: B) The government can take away money if a scientist is not following ethical standards

Explanation: hope this helped :)

The government control scientific research by taking  away money if a scientist is not following ethical standards. Therefore, the correct option is option B.

While it is crucial to recognise that the government's role in scientific research is varied and extends beyond the control of ethical standards, funding agencies and institutions frequently require researchers to follow particular ethical norms and standards when conducting scientific investigations. Failure to adhere to these ethical norms may result in the loss or denial of research funding.

However, it is critical to recognise that the government's role in scientific research extends beyond simply enforcing ethical norms. Governments can also fund and support specific research areas or priorities, create regulations and guidelines for research practises, encourage researcher collaboration, provide infrastructure and resources, and establish policies that shape the overall direction and focus of scientific research.

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Answer:

.............increases

Answer: 45.983 g CBr₄

Explanation:

To convert from moles to grams, you know that we will need molar mass and Avogadro's number.

Avogadro's number: 6.022×10²³ molecules/mol

Molar mass: 331.627 grams/mol

Now that we have what we need, you can use these to solve for grams. [tex]8.35*10^2^2molecules CBr_{4} *\frac{1mol}{6.022*10^2^3molecules} *\frac{331.627 g}{1 mol} =45.983 g[/tex]

Our final answer is 45.983 g CBr₄.

Answer:

See the answer below

Explanation:

Using the dilution equation:

m1v1 = m2v2

m1 =100 μM, v1 = ?, v2 = 10 mL

In order to prepare 80 μM, then m2 = 80 μM

v1 = [tex]\frac{80*10}{100}[/tex] = 8 mL

In order to prepare 60 μM

v1 = [tex]\frac{60*10}{100}[/tex] = 6 mL

In order to prepare 40 μM

v1 = [tex]\frac{40*10}{100}[/tex] = 4 mL

In order to prepare 20 μM

v1 = [tex]\frac{20*10}{100}[/tex] = 2 mL

Since the final solution has to be up to the 10 mL mark, the complete table would be:

Target Concentration(μM)       Volume of stock(mL)        Volume of water(mL)

              20                                           2                                            8

              40                                           4                                             6

              60                                           6                                             4

              80                                           8                                             2

Answer:

680

Explanation:

Move the decimal 2 to the right.

When a number is written using only the digits of the number, that is considered standard notation. 6.8 × 10²  is converted into standard notation by shifting two decimal to the right side, then it became 680.

A form of writing a certain number, an equation, or an expression in a way that adheres to set norms is known as a standard notation. For instance, 4,500,000,000 years is how 4.5 billion years is written.

When a number is written using only the digits of the number, that is considered standard notation. Since words are not used in conventional number notation, this is the way that numbers are typically written.

The stages to writing a number in its standard form are as follows: Write the first digit of the supplied number in step one. Step 2: After the first number, add the decimal point. Step 3: Next, count how many digits there are in the supplied number after the first one and express that number as a power of 10.

Thus, the standard notation is 680.

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Answer:

you can use math wa, it helps

Answer:

Instrumental methods

surface analysis

high performance liquid chromatography

atomic spectroscopy

potentiometry

Classical methods

precipitation titration

gravimetric analysis

Explanation:

Instrumental methods of analysis are those analytical methods in which the responsibility of detection has been removed from human beings and placed on automated instruments while classical methods are those analytical methods in which the responsibility of detection remains the responsibility of human beings.

Many instrumental methods such as HPLC rely on computer screens as readout devices.

Answer:

This replacements will make the compound less basic and more acidic

Explanation:

Replacing amino groups (-NH₂) which act as bases [because of there ability to accept hydrogen ion (H⁺)] with carboxyl group (-COOH) which acts as acid [because of it's ability to donate hydrogen ion (H⁺)] in a compound changes the property of the compound to be less basic and more acidic.

Answer:

The structures are shown in the attachments.

Explanation:

Please see the attachments below for the structures.

Explanation:

There is only one environment denoted as 'a'.

Using the (n+1) rule to determine the multiplicity, m

where is the number of neighboring Hydrogen, then

Since, n = 0, then

m = 0 + 1 = 1 (which means singlet)

Hence, one singlet

There are two environments denoted as 'a' and 'b'

For 'a' ; n = 6

Hence, m = n + 1

m = 6 + 1  = 7 (this means septet)

For 'b'; n = 1

then, m = n + 1

m = 1 + 1  = 2 (this means doublet)

Hence, one septet, one doublet

There are two environments denoted as 'a' and 'b'

For 'a' ; n = 2

then, m = n + 1

m = 2 + 1  = 3 (this means triplet)

For 'b' ; n = 2

then, m = n + 1

m = 2 + 1  = 3 (this means triplet)

Hence, two triplets

There are three environments denoted as 'a', 'b', and 'c'

For 'a' ; n = 0

Hence, m = n + 1

m = 0 + 1  = 1 (this means singlet)

For 'b' ; n = 3

then, m = n + 1

m = 3 + 1  = 4 (this means quartet)

For 'c' ; n = 2

then, m = n + 1

m = 2 + 1  = 3 (this means triplet)

Hence, one singlet, one triplet, and one quartet

Answer:

1. A. 10°C

2. A. Boiling point

3. A. Less than liquids.

Explanation: