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3 years ago

Which sample of matter has a crystal structure?

1 answer:

3 0

A crystalline structure is any structure of ions, molecules, or atoms that are held together in an ordered, three-dimensional arrangement. It is composed of a unit cell, a set of atoms arranged in a particular way; which is periodically repeated in three dimensions on a lattice.

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8. An atom has 9 protons, which element is it?

ValentinkaMS [17]

Answer:

fluorine

Explanation:

The element fluorine has 9 protons and 9 electrons.

3 0

3 years ago

Read 2 more answers

Acetanilide has a solubility of 1.00 g/185 ml in 25 oc water and 1.00 g/20 ml in 100 oc water. what is the minimum volume of wat

Likurg_2 [28]

In the crystallization process the solid compound is dissolved in the solvent at elevated temperature and the crystallize product obtained by slow cooling of the solution. Here the solubility of acetanilide at 100°C is 1g per 20mL of water. Thus to dissolve 500mg of acetanilide at high temperature that is 100°C we need 10mL of water.

Now at 25°C after the re-crystallization there will be some amount of dissolve acetanilide. Which can be calculated as- 185mL of water is needed to dissolve 1g or 1000mg of acetanilide at 25°C. Thus in 10mL of water there will be $\frac{10X1000}{185}=54.05$ gmg of acetanilide.

6 0

3 years ago

Question 1: Which of the following statement is false about conjugated systems?

valkas [14]

Answer:

A conjugated system can only contain two alkenes: False

B. A cumulated diene is less stable than an isolated diene.

False

Explanation:

A. A conjugated system is more stable than an unconjugated system.: True

Due to resonance a conjugated system is more stable.

B. The s-trans isomer is favored over the s-cis isomer.: True

Due to repulsion in s-cis isomer they are less stable.

C. A conjugated system has multiple resonance structures. True

This is the reason they are stable.

D. A conjugated system can only contain two alkenes: False

A conjugated system may have may alternate double and triple bonds.

2) A trans alkene releases less heat upon hydrogenation than a cis alkene.

True

Trans alkenes are more stable than cis alkene. Thus heat of hydrogenation of trans alkene is less than cis alkene.

B. A cumulated diene is less stable than an isolated diene.

False

C. Multiple products can always form when treated a conjugated diene with HBr. True

There can be 1,2 or 1,4 addition

D. Conjugated systems arise only between sp2-hybridized atoms.

True

Conjugation allows resonance which is possible in sp2 systems

E. Conjugated double bonds involve unhybridized p-orbitals aligned with each other

True

The double bond is formed as pi bond due to side ways overlapping of unhybridized p orbitals

8 0

3 years ago

Question:

Dahasolnce [82]

If you can have more than 1 answer then the dependent variable is graphed on the Y-axis and and is usually used for comparison since they are usually the experiment results. If you can only have one answer then the dependent variable is graphed on the y-axis.

8 0

3 years ago

Which of the following correctly describes a compound?

Oksi-84 [34.3K]

I think its c, it makes sense to me to be c

7 0

3 years ago

Read 2 more answers