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3 years ago

Why do atomic models change over time

1 answer:

4 0

The model of the atom has dramatically changed over many many years.We learned atoms make up different substances and are the smallest particles of matter, which have subatomic particles that are very small portions of matter. At first scientist only thought there were electrons which are negatively charged.

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Which wave has a disturbance that is perpendicular to the wave motion?

Otrada [13]

It B I just took the test ;)

7 0

3 years ago

Read 2 more answers

Name the following compound:

igomit [66]

Answer:

3,5-dimethyl-2-octene

Explanation:

When naming an organic molecule with a double bond, the chain has to include the double bond. This means that there are 8 carbon atoms on the central chain. The molecule is octene. The double bond is after the second carbon, making it 2-octene. You can't say that its 6-octene because you want to have the smallest number possible in front.

The molecules attached are two methyl groups. Since you have two methyl groups, the name will be dimethyl. Start counting from the side closest to the double bond. This gives you a 3, 5-dimethyl group.

5 0

3 years ago

Which is most likely true about electronegativity?

VikaD [51]

Electronegativity is the tendency of an element to attract the bonded electrons towards itself. In a group, as the atomic radius increases electronegativity decreases as the outermost electron is far away from the nuclear attraction. In a period, the atomic size decreases. So, the effective nuclear charge experienced by the outermost shell increases. Therefore, across a period the electronegativity increases as the increased effective nuclear charge leads to the attraction of bonded electrons with greater ease.

Therefore the correct answer is c, electronegativity tends to increases across a period.

8 0

3 years ago

Bromine (63 g) and fluorine (60 g) are mixed to give bromine trifluoride. a) Write a balanced chemical reaction. b) What is the

fiasKO [112]

Answer:

a) Br2 + 3F2 → 2BrF3

b) Br2 is the limiting reactant.

c) There will be formed 86.3 grams of BrF3

d) There will remain 0.326 moles of F2 = 12.97 grams

Explanation:

Step 1: The balanced equation

Br2 + 3F2 → 2BrF3

Step 2: Given data

Mass of Bromine = 63grams

Mass of fluorine = 60 grams

percent yield = 80%

Molar mass of bromine = 79.9 g/mol =

Molar mass of fluorine = 19 g/mol

Molar mass of bromine trifluoride = 136.9 g/mol

Step 3: Calculating moles

Moles Br2 = 63 grams / (2*79.9)

Moles Br2 = 0.394 moles

Moles F2 = 60 grams / (2*19.9)

Moles F2 = 1.508

For 1 mole Br2 consumed, we need 3 moles of F2 to produce 2 moles of BrF3

Br2 is the limiting reactant. It will completely be consumed (0394 moles).

There will react 3*0.394 = 1.182 moles of F2

There will remain 1.508 - 1.182 = 0.326 moles of F2 = 12.97 grams

Step 5: Calculate moles of BrF3

For 1 mole Br2 consumed, we need 3 moles of F2 to produce 2 moles of BrF3

So there is 2*0.394 moles = 0.788 moles of BrF3 moles produced

Step 6: Calculate mass of BrF3

mass = Moles * Molar mass

mass of BrF3 = 0.788 moles * 136.9 g/mol = 107.88 grams = Theoretical yield

Step 7: Calculate actual yield

% yield = 0.80 = actual yield / theoretical yield

actual yield = 0.80 * 107.88 grams = 86.3 grams

actual yield = 86.3 grams

7 0

2 years ago

Perspex and polythene are two examples of what?

erma4kov [3.2K]

Perspex and polythene are good examples of insulators.

3 0

3 years ago