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MArishka [77]
3 years ago
15

Which of the following is not a clue that a chemical reaction has taken place? *

Chemistry
1 answer:
DaniilM [7]3 years ago
7 0

Answer:

A pure solid is heated and turns into a pure liquid.

Explanation:

No colour change recorded, only change of state, hence this is a physical change - physical changes I.e. change of state and temperature are not chemical reactions.

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The IR spectrum of a solid can be taken by dissolving it to create a solution. An appropriate solvent is Choose... because its I
irina [24]

Answer:

An appropriate solvent is <u>only in the fingerprint region. </u>

Explanation:

For scientists to study the infrared spectra of substances in the various states of matter, solutions are usually made with solvents. However, it has been noted that some of these solvents can interfere with the reaction spectra or be absorbed within the range of the solutes. A solution to this problem is using the right solvents with non-interfering infrared spectrum and which have no chemical effect on the solute.

The bands formed by the solvent should also be located in the the fingerprint spectrum. Examples of solvents used to achieve this and which meet up these requirements include, Carbon tetrafluoride and Carbon disulfide.  

5 0
3 years ago
A beaker contains 0.125 L of a 3.00 M solution. If the volume goes up to 0.325 L, what is the new molarity?
igor_vitrenko [27]

Answer:

1.15 M

Explanation:

Step 1: Given data

  • Initial volume (V₁): 0.125 L
  • Initial concentration (C₁): 3.00 M
  • Final volume (V₂): 0.325 L
  • Final concentration (C₂): ?

Step 2: Calculate the final concentration of the solution

We want to prepare a dilute solution from a concentrated one by adding water. We can calculate the concentration of the dilute solution using the dilution rule.

C₁ × V₁ = C₂ × V₂

C₂ = C₁ × V₁/V₂

C₂ = 3.00 M × 0.125 L/0.325 L = 1.15 M

8 0
2 years ago
if an iron nail is placed in a glass of water the nail will sink. Is the density of iron smaller than or larger than the density
Gala2k [10]
It has  more density when it sinks because the water pushes away thats why people float they are less dense 
5 0
3 years ago
An atom that contains 22 protons,
Westkost [7]

Answer: 45

Explanation:

Recall that mass number = number of protons + number of neutrons. Hence, the mass number of the atom

= 22 + 23

= 45

Furthermore, the atomic number is equal to the number of protons. Hence, since the number of protons is 22. the atom has an atomic number of 22

Thus, An atom that contains 22 protons,

23 neutrons, and 22 electrons would have a mass of approximately 45

6 0
3 years ago
Read 2 more answers
Calculate the ΔG°rxn using the following information at 298K. 2 HNO3(aq) + NO(g) → 3 NO2(g) + H2O(l) ΔG°rxn = ? ΔH°f (kJ/mol) -2
Mkey [24]

Answer:

ΔG°rxn = +50.8 kJ/mol

Explanation:

It is possible to obtain ΔG°rxn of a reaction at certain temperature from ΔH°rxn and S°rxn, thus:

<em>ΔG°rxn = ΔH°rxn - T×S°rxn (1)</em>

In the reaction:

2 HNO3(aq) + NO(g) → 3 NO2(g) + H2O(l)

ΔH°rxn = 3×ΔHfNO2 + ΔHfH2O - (2×ΔHfHNO3 + ΔHfNO)

ΔH°rxn = 3×33.2kJ/mol + (-285.8kJ/mol) - (2×-207.0kJ/mol + 91.3kJ/mol)}

ΔH°rxn = 136.5kJ/mol

And S°:

S°rxn = 3×S°NO2 + S°H2O - (2×S°HNO3 + S°NO)

ΔH°rxn = 3×0.2401kJ/molK + (0.0700kJ/molK) - (2×0.146kJ/molK + 0.2108kJ/molK)

ΔH°rxn = 0.2875kJ/molK

And replacing in (1) at 298K:

ΔG°rxn = 136.5kJ/mol - 298K×0.2875kJ/molK

<em>ΔG°rxn = +50.8 kJ/mol</em>

<em />

7 0
3 years ago
Read 2 more answers
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