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mina [271]
3 years ago
7

Where was silk first discovered find out the answer​

Chemistry
1 answer:
steposvetlana [31]3 years ago
3 0

Answer:

China

Explanation:

The production of silk originates in China in the Neolithic (Yangshao culture, 4th millennium BC). Silk remained confined to China until the Silk Road opened at some point during the later half of the 1st millennium BC.

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a 25 ml sample of gas is in a syringe at 22C if it was cool down to 0 C what will the volume of the gas become
Tpy6a [65]

Answer: 0.023 liters

Explanation:

Given that,

Original volume of gas (V1) = 25mL

[convert 25mL to liters

If 1000ml = 1L

25ml = 25/1000 = 0.025L]

Original temperature of gas (T1) = 22°C

[Convert 22°C to Kelvin by adding 273

22°C + 273 = 295K]

New volume of gas (V2) = ?

New temperature of gas (T2) = 0°C

[Convert 0°C to Kelvin by adding 273

0°C + 273 = 273K]

Since volume and temperature are given while pressure is held constant, apply the formula for Charle's law

V1/T1 = V2/T2

0.025L/295K = V2/273K

To get the value of V2, cross multiply

0.025L x 273K = 295K x V2

6.825L•K = 295K•V2

Divide both sides by 295K

6.825L•K/295K = 295K•V2/295K

0.023 L = V2

Thus, the new volume of the gas will be 0.023 litres

6 0
3 years ago
Scoring Scheme: 3-3-2-1 Use one of your experimentally determined values of k, the activation energy you determined, and the Arr
Lena [83]

Answer:

K = 2.7x10⁻⁵ at 25ºC

Explanation:

A way to write Arrhenius equation is:

ln K = - Ea/R × (1/T) + lnA

If you graph ln K as Y and 1/T as X (Absolute temperature in K), the equation you will obtain is:

Y = -13815X +35.817

R² = 0.9927

(Taking the last k point as 0.0386) (ln 0.0386), <em>0.1386 has no sense</em>)

Your slope is -13815

-13815K = - Ea/R

-13815K×8.314J/molK = 114858J/mol = Ea

And your intercept =

lnA = 35.817

A = 3.59x10¹⁵

Now, you want to know rate constant at 25ºC = 298.15K. Replacing in the equation (Where Y is ln (activation energy) and X is 1/T):

Y = -13815X +35.817

Y = -13815(1/298.15K) +35.817

Y = -10.5187

lnK = -10.5187

<h3>K = 2.7x10⁻⁵ at 25ºC</h3>

8 0
3 years ago
I’m doing a project in school on liquids and gasses and I wanted to know if air conditioning is a gas?
NeX [460]

The AC unit uses a refrigerant generally a chemical called freon to cool the air in a house. The unit evaporates freon and uses the result of this evaporation cycle to circulate cool air. ... Freon is a gas. The AC unit compresses this cool gas, causing it to become very hot.

5 0
3 years ago
Too much can lead to diabetes and can be stored as fat in the body
ohaa [14]

Answer:B.carbohydrates

Explanation:

7 0
2 years ago
The atomic number of Re is 75. The atomic mass of one of its isotopes is 186. How many neutrons are in an atom of this isotope?
USPshnik [31]

Answer:

B.111

Explanation:

Atomic mass = number of protons(or atomic number) + number of neutrons

186 = 75 + number of neutrons

number of neutrons = 186 -75 = 111

7 0
3 years ago
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