test results indicated a chemical change has taken place ​

Answers

Answer 1

Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color chage, formation of a precipitate, formation of a gas, odor change, temperature change.

Related Questions

For the following amino acid, the name, three-letter abbreviation, or one-letter abbreviation is given. Complete the missing information.Name: proline Three letter abbreviation:____________One letter abbreviation:________

Answers

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.

Calculate the mass in grams of 8.35 × 1022 molecules of CBr4.

Answers

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.

How does the government control scientific research?
O A. Scientists are dependent upon the government to set ethical
standards.
B. The government can take away money if a scientist is not
following ethical standards.
O C. The government determines which experiments are important.
D. Scientists can do only research that the government supports.

Answers

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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convert 6.8 × 10^2 to standard notation.

Answers

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.

What is standard notation ?

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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The diameter of an atom is approximately 1 * 10 ^ - 10 * m . What is the diameter in decimeters?

Answers

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.

What is the A# of fluoride-19?​

Answers

Answer:

atomic number of fluorine

is 9

What is the maximum length of a polyethene chain with molar mass 10^6 and monomer length 2.5?

Answers

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 .

How would replacing many amino groups with carboxyl groups change the properties of the compound?

Answers

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.

Is burning sugar a chemical or physical change? Please provide explanation

Answers

Answer:

It is a chemical change

Explanation:

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

It be a chemical change my dude

Sort the following analytical techniques as either classical methods or instrumental methods.
a) surface analysis
b) precipitation titration
c) gravimetric analysis
d) high performance liquid chromatography
e) potentiometry
f) atmoic spectroscopy

Answers

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.

Monobromination of toluene gives a mixture of three bromotoluene products. Draw and name them.

Answers

Answer:

o-bromotoluene, m-bromotoluene  and p-bromotoluene.

Explanation:

Hello,

In this case, on the attached picture you will find the reaction which yields o-bromotoluene as the first product, m-bromotoluene as the second product and p-bromotoluene as the last one since the substitution could be done at the second (ortho), third (meta) or fourth (para) carbons on the toluene.

Regards.

What is the density of a silver coin from the following data:
Mass of silver coin 6.581 g
Volume of coin and water 23.7 mL
Volume of water alone 23.1 mL

The answer is assumed to be in g/mL. Please type a numeric value only.​

Answers

Answer:

you can use math wa, it helps

Ocean water becomes colder; the density of ocean water increases or decreases?

Answers

Answer:

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

Question 13 of 16
The mass of a piece of metal is 25.4253 grams. When the piece of
metal was dropped into a graduated cylinder that had an initial water
volume of 6.85 cm, the total volume was 9.84 cm? What is the
density of the piece of metal in g/cm??

Answers

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.

Can someone please help me with these questions!!!!!!

Answers

the answer question 2 is a. boiling point

Answer:

1. A. 10°C

2. A. Boiling point

3. A. Less than liquids.

Explanation:

which of these substances are most likely crystalline solids?

Answers

Answer:

diamond

sugar

rubber

salt (NaCl)

wood

ice

flour

Answer:

diamond

sugar

salt

ice

Explanation:

Which of the following is in intensive property a. mass b. magnetism c shape D. volume

Answers

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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A car drives on a road at a constant speed of 50 miles/hour.
The forward force of the car is ________________
the opposing friction and air
resistance forces.
The forward force of the car and the opposing friction and air resistance forces are ____________
( !!

Answers

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:

Draw structures for compounds that meet the following descriptions in proton NMR:a) C2H6O; one singletb) C3H7Cl; one doublet and one septetc) C4H8Cl2O; two tripletsd) C4H8O2; one singlet, one triplet, and one quartet

Answers

Answer:

The structures are shown in the attachments.

Explanation:

Please see the attachments below for the structures.

Explanation:

For the structure in (a)

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

For the structure in (b)

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

For the structure in (c)

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

For the structure in (d)

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

To prepare 100.0 mL of a 0.0525 M solution of NaCl in water, what mass of sodium chloride is needed? The
molar mass of NaCl is 58.44 g/mol.

Answers

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

hey can anyone help me with organic chemestry?​

Answers

Organic chemistry is

Can someone please help me w these chemistry conversion? 1. The density of Mercury is 13.6 g/mL. What is the volume of mercury, in quarts has a mass of 95.0 ounces? 2. Tetrachloroethylene, also called PERC, has a density of 1.62 g/mL. It was formerly used as a dry cleaning solvent. What is the mass in pounds of PERC contained in a 55.0 gallon drum? 3. Osmium is the most dense element having a density of 22.5 g/cm^3 Calculate the density of osmium in kg/m^3. 4. The density of Iron is 7.50 g/cm^3. What is the mass, in pounds, of a cube of iron that measures 5.00 cm on a side? 5. Lead has a density of 10.5 g/cm^3. What is the diameter of a lead ball that has a mass of 500.0 g? Report answer in cm.

Answers

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

Suppose now that you wanted to determine the density of a small crystal to confirm that it is graphite. From the literature, you know that graphite has a density of 2.25 g/cm^3. How would you prepare 20.0 mL of the liquid mixture having that density from pure samples of CHCl3 (d = 1.492 g/mL) and CHBr3 (d = 2.890 g/mL)? (Note: 1 mL = 1 cm^3.)

Answers

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.

Enter a balanced equation for the reaction between aqueous lead (II) nitrite and aqueous lithium chloride to form solid lead (II) chloride and aqueous lithium nitrite.

Answers

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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In reading a line drawing, how do you know where atoms of these elements are in the structure if they are missing from the drawing?

Answers

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.

The stock solution is 100 μM the protocol calls for 10 mL solution of 80, 60, 40 and 20 μM. Compute the table.Target Concentration(μM) Volume of stock(mL) Volume of water(mL)20406080

Answers

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

An atom's Lewis dot structure has four dots. Which of the following elements could it be, and why?

Answers

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

Explanation: Just did this quiz

Answer:carbon

Explanation:

You are comparing a reaction that produces a chemical
change and one that produces a physical change. What
evidence could you use to determine which type of
change is occurring?

Answers

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.

How is it possible for water to be polar but uncharged?

Answers

Water is polar in that the hydrogen atoms bear a partial positive charge, whereas the oxygen atom bears a partial negative charge, due to the electronegativity of oxygen. ... Water disrupts ionic bonds and hydrogen bonds.

the weight of a sack potato in india is 50kgf. will the weight increase or decrease in bhutan. why​

Answers

Answer:

Assume that the sack was initially close to the sea level. Its weight will increase even though its mass stays the same.

Explanation:

The weight of an object typically refers to the size of the planet's gravitational attraction (a force) on this object. That's not the same as the mass of the object. The weight of an object at a position depends on the size of the gravitational field there; on the other hand, the mass of the object is supposed to be same regardless of the location- as long as the object stays intact.

Let [tex]g[/tex] denote the strength of the gravitational field at a certain point. If the mass of an object is [tex]m[/tex], its weight at that point will be [tex]m \cdot g[/tex].

Indeed, [tex]g \approx 9.81\; \rm N \cdot kg^{-1}[/tex] on many places of the earth. However, this value is accurate only near the sea level. The equation for universal gravitation is a more general way for finding the strength of the gravitational field at an arbitrary height. Let [tex]G[/tex] denote the constant of universal gravitation, and let [tex]M[/tex] denote the mass of the earth. At a distance [tex]r[/tex] from the center of the earth (where

[tex]\displaystyle g \approx \frac{G \cdot M}{r^2}[/tex].

The elevation of many places in Bhutan are significantly higher than that of many places in India. Therefore, a sack of potato in Bhutan will likely be further away from the center of the earth (larger [tex]r[/tex]) compared to a sack of potato in India.

Note, that in the approximation, the value of [tex]g[/tex] is (approximately, because the earth isn't perfectly spherical) inversely proportional to the distance from the center of the planet. The gravitational field strength

On the other hand, the weight of an object of fixed mass is proportional to the gravitational field strength. Therefore, the same bag of potatoes will have a smaller weight at most places in Bhutan compared to most places in India.

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