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nika2105 [10]
3 years ago
12

A food item that is left out of the refrigerator turns brown and forms bubbles and gas. What are the signs that this is a chemic

al reaction? Check all that apply. * 2 points Heat is produced Bubbles appear. The color changes. Heat is absorbed. A precipitate forms.
Chemistry
2 answers:
Alik [6]3 years ago
4 0

Answer: The answers are c and e.

Explanation:

marshall27 [118]3 years ago
3 0

Answer:

bubbles appear, color changes

Explanation:

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An 84.84 g sample of steel is added to a 100-ml graduated cylinder with 45.0 ml of water. if the resulting water level is 55.5 m
Elden [556K]
The volume of the steel that is described above is obtained by water displacement method. This means that the volume can be calculated by subtracting the initial volume from the final volume. This will give us an answer of,
                             volume of steel = 55.5 mL - 45 mL = 10.5 mL

6 0
3 years ago
Read 2 more answers
Which of the following describes carbon dioxide? O Has polar covalent bonds and is a polar molecule O Has non-polar covalent bon
OLga [1]

Answer: Option "Has polar bonds and is a non-polar molecule" is the correct answer.

Explanation:

A covalent compound is defined as the compound in which there will be sharing of electrons between the combining atoms.

An ionic compound is defined as the compound in which there will be transfer of electrons from one atom to another.

  • A non-polar covalent compound is defined as the compound in which there will be equal sharing of electrons between the combining atoms.

For example, a chlorine atom has 7 valence electrons.

So, when a chlorine atom chemically combines with another chlorine atom then there occurs equal sharing of electrons.

Hence, molecule Cl_{2} is formed which is non-polar covalent compound in nature with non-polar covalent bond.

  • A polar covalent bond is defined as the bond in which there will be unequal sharing of electrons between the combining atoms.

For example, a carbon atom has 4 valence electrons and an oxygen atom has 6 valence electrons.

To complete their octet a carbon atom needs 4 more electrons and an oxygen atom needs 2 more electrons.

And, when one carbon and two oxygen atoms chemically combine together then there occurs unequal sharing of electrons.

Hence, a polar covalent compound CO_{2} is formed.

Since, oxygen is more electronegative than carbon atom. Hence, dipoles in the linear carbon dioxide molecules will cancel out each other.

Therefore, a carbon dioxide molecule is non-polar compound that has polar covalent bonds.

Thus, we can conclude that the statement, has polar bonds and is a non-polar molecule, correctly describes carbon dioxide.

8 0
3 years ago
Write the net ionic equation describing the reaction between aluminum metal and Fe3+ ions in solution that produces dissolved Al
leonid [27]

Answer:

Al (s) + 3Fe3+ (aq) ---> Al3+ (aq) + 3Fe2+(aq)

Explanation:

atoms become positive (or less negative) ions when they lose electrons. They become negative (or less positive) ions when they gain electrons, since each electron (e-) has a charge of -1.

So, since Al changes to Al3+ which is positive, it loses electrons. And when Fe3+ changes to Fe2+, it becomes less positive, so it gained electrons.

Now, write the half (balanced) equations:

Al ---> Al3+ + 3e-

Fe3+ + e- ----> Fe2+

To combine both equations, we have to eliminate electrons. To do so, make sure both half equations have the same no. of electrons. We can multiply the equation of Fe by 3 so that it has 3 electrons.

3Fe3+ + 3e- ----> 3Fe2+

Finally, we can combine both equations (remember to eliminate the electrons).

Al (s) + 3Fe3+ (aq) ---> Al3+ (aq) + 3Fe2+(aq)

Check to see if both sides of the equation have equal charges. Ions always have an aqueous state.

5 0
3 years ago
You are interested in thymol in mouthwash. The manufacturer lists the active ingredients as thymol (0.064%), menthol (0.042%), e
frez [133]

Answer:

a) Thymol represents a minor concentration.

b) Of the ingredients listed, the ones that qualify as being contained in trace amounts are the ones with concentrations less than 0.01%, 100ppm or 0.1mg/L. And in this question, none of the given concentrations is less than 0.01%. Maybe one of the other constituents whose concentrations weren't given is in trace amounts.

c) The mouthwash brought for analysis is the sample.

d) Thymol is the analyte.

e) The matrix is every component of the mouthwash sample apart from the analyte constituent, thymol.

Menthol, eucalyptol, methyl salicylate, caramel, water, alcohol in addition to sodium benzoate, color, poloxamer 407 and benzoic acid are all member substances of the matrix.

f) The blank can contain every constituent apart from the analyte constituent, thymol.

Explanation:

a) The composition range for major, minor and trace components are given thus.

1-100% Major

0.01-1% Minor

1 ppb to 100ppm Trace

<1ppb ultra trace

In Chemistry terms,

•Major constituents: Substances in concentrations over 1mg/L

•Minor constituents: Substances in concentrations between 1mg/L and 0.1 mg/L

•Trace constituents: Substances in concentrations under 0.1 mg/L

Hence, thymol with a concentration of 0.064% represents a minor constituent.

b) Of the ingredients listed, the ones that qualify as being contained in trace amounts are the ones with concentrations less than 0.01%, 100ppm or 0.1mg/L. And in this question, none of the given concentrations is less than 0.01%. Maybe one of the other constituents whose concentrations weren't given is in trace amounts.

c) In chemical analysis or Analytical chemistry, a sample is a portion of material selected from a larger quantity of material.

Therefore, for this question, the mouthwash is the sample.

d) In Analytical Chemistry, an analyte or analyte component is a substance or chemical constituent that is of interest in an analytical procedure.

For this question, the analyte is thymol; the constituent the analyser is interested in.

e) In chemical analysis, matrix refers to the components of a sample other than the analyte of interest.

Therefore, the matrix is every component of the mouthwash sample apart from the analyte constituent, thymol.

Menthol, eucalyptol, methyl salicylate, caramel, water, alcohol in addition to sodium benzoate, color, poloxamer 407 and benzoic acid are all member substances of the matrix.

f) A blank solution is a solution containing little to no analyte of interest, so, the blank can contain every constituent apart from thymol.

Hope this helps!

7 0
4 years ago
Pls helppp
defon

The heat absorbed to raise temperature : Q = 31350 J

<h3>Further explanation </h3>

Given

m = mass = 150 g

Δt = Temperature difference : 50 °C

Required

Heat absorbed

Solution

Heat can be formulated

<em> Q = m.c.Δt </em>

The specific heat of water = c = 4.18 J/g °C  

Input the value :

Q = 150 x 4.18 x 50

Q = 31350 J

6 0
3 years ago
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