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Rudiy27
2 years ago
14

Describe two observations you might make when a chemical change occurs

Chemistry
1 answer:
Sav [38]2 years ago
7 0
The first one is color change
Second is the precipitate present
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Convert 2.83 days into seconds
katovenus [111]
2.83 days into hours  = 2.83 x 24 = 67.92 hours

67.92 hours into minute = 67.92 x 60 = 4075.2 minutes

4075.2 minutes into seconds = 4075.2 x 60 = 244,512 seconds.
5 0
3 years ago
What characteristic of an element’s atoms always determines the element’s identity?
dmitriy555 [2]

Answer:

Number of protons

Explanation:

There are three sub atomic particles. These are;

- Protons

- Electrons

- Neutrons

Among these three particles, only one determines the identity of the element. This is the Protons. The number of protons which is also called the atomic number determines the identity of an element. For instance, atom with one proton is Hydrogen and n other element can have atomic number of one.

6 0
3 years ago
Which nuclei are most useful for organic structure determination using nmr spectroscopy? (select all that apply.)?
Mumz [18]
Hydrogen-1, Carbon-13, Nitrogen-15, Fluorine-19, and Phosphorus-31 are the most useful. Out of these, Hydrogen-1 and Carbon-13 in NMR are the most useful nuclei because the these atoms are the most commonly present in organic molecules.
5 0
3 years ago
Convert 5.28 x 1019 molecules of C6H1206 to grams.
nlexa [21]

Answer:

m=0.0158g

Explanation:

Hello there!

In this case, it is possible to comprehend these mass-particles problems by means of the concept of mole, molar mass and the Avogadro's number because one mole of any substance has 6.022x10²³ particles and have a mass equal to the molar mass.

In such a way, for C₆H₁₂O₆, whose molar mass is about 180.16 g/mol, the referred mass would be:

m=5.28x10^{19}molecules*\frac{1mol}{6.022x10^{23}molecules}*\frac{180.16g}{1mol}\\\\m=0.0158g

Best regards!

5 0
3 years ago
Predict the sign of ΔSsys for each of the following processes. Which are positive? (a) Gasoline vapors mix with air in a car eng
OLEGan [10]

Answer:

Positive: a and b

Negative: c

Explanation:

The entropy (S) is the measure of the randomness of the system, and it intends to increase. The randomness can be determined by the energy of the molecules, their velocity and how distance they are between the other molecules.

When the entropy increases, ΔS is positive, when the entropy decreases, ΔS is negative. So, when gasoline mix with air in a car engine, the process intends to continue, the randomness increases and ΔS is positive. When hot air expands, the distance between the molecules increases, so ΔS is positive.

But, when humidity condenses, the molecules stay closer, so there's a decrease in the randomness, then ΔS is negative.

6 0
3 years ago
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