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3 years ago

Briefly explain why there is a constant temperature plateau in the cooling curve

1 answer:

4 0

This plateau is where a phase change occurs. Likely, this cooling curve observes the changing of a liquid into a solid (so that the temperature is quantifiable). As something cools, it’s losing energy to the surroundings; when a phase change occurs, like liquid to solid, energy isn’t lost directly from the atom, but instead the energy maintained by free motion of the atom is used. This lack of motion reduces it into a lattice (all while maintaining a constant internal energy), finalizing the phase change, after which energy is lost directly from the atom again.

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Relate dark matter to the development of the universe after the Big Bang. In 3-5 sentences, speculate on how the development of

Alenkinab [10]

Answer:

Dark matter makes up 85% of the mass of the universe. Dark matter is not directly observable because it doesn't interact with any electromagnetic wave. In the development of the universe, without dark matter, the universe will not function, move or rotate as it does now (this speculation led to the quest to find the anomaly of mass and energy in the known universe, eventually leading to the idealization of dark matter) and will not have enough gravitational force to hold it together. After the big bang,<em> the presence of dark matter and energy ensured that the newly formed universe didn't just float away, rather, it provided enough gravitational force to hold the universe while still allowing it to expand sufficiently</em>.

The development of the universe would have been different without the universe in the sense that the young universe won't have enough mass to hold it together, and the universe would have simply floated apart. The behavior of the universe would have been different from what we observe now, and some physical laws that applies now will not apply to the universe.

6 0

3 years ago

Vitamin C contains only carbon, hydrogen, and oxygen. When a 1.00 g was combusted, 1.4991 g of CO2 and 0.4092 g of H2O were obta

Alina [70]

The empirical formula for this vitamin : C₃H₄O₃

<h3>Further explanation </h3>

The empirical formula is the smallest comparison of atoms of compound =mole ratio of the components

The principle of determining empirical formula

Determine the mass ratio of the constituent elements of the compound.
Determine the mole ratio by dividing the percentage by the atomic mass

Mass of C in CO₂ :(MW C = 12 g/mol, CO₂=44 g/mol)

$\tt \dfrac{12}{44}\times 1.4991=0.409~g$

Mass of H in H₂O :(MW H = 1 g/mol, H₂O = 18 g/mol)

$\tt \dfrac{2.1}{18}\times 0.4092=0.0455~g$

Mass O = Mass sample - (mass C + mass H) :

$\tt 1-(0.409+0.0455)=0.5455~g$

mol ratio C : H : O =

$\tt \dfrac{0.409}{12}\div \dfrac{0.0455}{1}\div \dfrac{0.5455}{16}\\\\0.0341\div 0.0455\div 0.0341\rightarrow 1\div 1.33\div 1=3\div 4\div 3$

5 0

3 years ago

Which substance can not be broken down by a

Tomtit [17]

Answer: (3) silicon

Explanation:

Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane $(C_2H_6)$ , propanone $(CH_3COCH_3)$ and water $(H_2O)$

7 0

3 years ago

WILL MARK BRANILEST

ahrayia [7]

Answer:

FeCl3 is the limiting reactant

O2 is in excess

Theoretical yield Cl2 = 9.84 grams

The % yield is 96.5 %

Explanation:

Step 1: Data given

Mass of FeCl3 = 15.0 grams

Moles O2 = 4.0 moles

Mass of Cl2 produced = 9.5 grams

Step 2: The balanced equation

4FeCl3 + 3O2 → 2Fe2O3 + 6Cl2

Step 3: Calculate moles FeCl3

Moles FeCl3 = mass FeCl3 / molar mass FeCl3

Moles FeCl3 = 15.0 grams / 162.2 g/mol

Moles FeCl3 = 0.0925 moles

Step 4: Calculate limiting reactant

FeCl3 is the limiting reactant. Because we have way more (more than ratio 3:4) moles O2 than FeCl3. It will completely be consumed (0.0925 moles). O2 is in excess. There will react = 0.069375 moles O2

There will remain 4.0 - 0.069375 = 3.930625 moles

Step 5: Calculate moles Cl2

For 4 moles FeCl3 we need 3 moles O2 to produce 2 moles Fe2O3 and 6 moles Cl2

For 0.0925 moles FeCl3 moles we'll have 6/4 * 0.0925 = 0.13875 moles Cl2.

Step 6: Calculate mass Cl2

Mass Cl2 = moles * molar mass

Mass Cl2 = 0.13875 moles * 70.9 g/mol

Mass Cl2 = 9.84 grams

Step 7: Calculate % yield

% yield = (actual yield / theoretical yield) * 100%

% yield = (9.5 grams / 9.84 grams ) * 100%

% yield = 96.5 %

The % yield is 96.5 %

4 0

3 years ago

Which of the below elements will not likely form an ionic bond?

Nookie1986 [14]

Answer:

Explanation:

I think this is right

3 0

3 years ago