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2 years ago

How can models demonstrate theories of our expanding universe?

Chemistry

1 answer:

Scilla [17]2 years ago

7 0

Answer:

Explanation:Puesto que la energía causante de la aceleración del espacio-tiempo no ha podido ser observada en forma directa, se ha dado en llamarla energía oscura. Dos candidatos teóricos que podrían hacer las veces de esta energía son una constante cosmológica no igual a cero (que pudo haber causado la inflación cósmica) y una energía repulsiva más general llamada quintaesencia.

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Daltons idea that atoms cannot be divided into smaller parts was disproved by the discovery of the.

tensa zangetsu [6.8K]

It was disproved by the discovery of the electrons

4 0

2 years ago

15.0 g of cream at 10.0 ℃ are added to an insulated cup containing 150.0 g of coffee at 78.6 °C. Calculate the equilibrium tempe

elena-14-01-66 [18.8K]

Answer:

The equilibrium temperature of the coffee is 72.4 °C

Explanation:

Step 1: Data given

Mass of cream = 15.0 grams

Temperature of the cream = 10.0°C

Mass of the coffee = 150.0 grams

Temperature of the coffee = 78.6 °C

C = respective specific heat of the substances( same as water) = 4.184 J/g°C

Step 2: Calculate the equilibrium temperature

m(cream)*C*(T2-T1) = -m(coffee)*c*(T2-T1)

15.0 g* 4.184 J/g°C *(T2 - 10.0°C) = -150.0g *4.184 J/g°C*(T2-78.6°C)

62.76T2 - 627.6 = -627.6T2 + 49329.36

690.36T2 = 49956.96

T2 = 72.4 °C

The equilibrium temperature of the coffee is 72.4 °C

7 0

3 years ago

Why does a heating curve have horizontal plateaus at certain points during the heating process? What is happening at those point

DENIUS [597]

A heating curve having horizontal plateaus at certain points during the heating process means that the process occurs at increase heating.

4 0

3 years ago

The mass fractions of a mixture of gases are 15 percent nitrogen, 5 percent helium, 60 percent methane, and 20 percent ethane wi

cricket20 [7]

Answer:

See explanation

Explanation:

Number of moles of each gas is

Nitrogen = 15/28 = 0.536 kmoles

Helium = 5/4 = 1.25 kmoles

Methane = 60/16 = 3.75 kmoles

Ethane = 20/30 = 0.67 kmoles

Total number of moles = 0.536 kmoles + 1.25 kmoles + 3.75 kmoles + 0.67 kmoles = 6.206 kmoles

Mole fraction of each gas;

Nitrogen = 0.536 kmoles/6.206 kmoles = 0.086

Helium = 1.25 kmoles/6.206 kmoles = 0.201

Methane = 3.75 kmoles/6.206 kmoles =0.604

Ethane = 0.67 kmoles/6.206 kmoles =0.108

Partial pressure of each gas;

Nitrogen = 0.086 * 1200 kPa = 103.2 kPa

Helium = 0.201 * 1200 kPa = 241.2 kPa

Methane = 0.604 * 1200 kPa = 724.8 kPa

Ethane = 0.108 * 1200 kPa = 129.6 kPa

Apparent specific heat at constant pressure;

Cp = (0.15 * 1.039) + (0.05 * 5.1926) + ( 0.6 * 2.2537) + (0.2 * 1.7662)

Cp = 2.12 KJ Kg-1 K-1

Cv = Cp- Ru/M

Cv= 2.12 - 8.314/16.12 = 1.604 KJ Kg-1 K-1

8 0

2 years ago

Need help with chemistry question

luda_lava [24]

Answer:

See explanation

Explanation:

In this case, we have to check two variables:

1) The leaving group

2) The carbon bonded to the leaving group.

Let's check one by one:

2-chloro-3-methylbutane

In this molecule, the leaving group is "Cl", the carbon bonded to the leaving group has two neighbors. Therefore, we have a secondary substrate.

1-phenylpropan-1-ol

In this molecule, the leaving group is "OH", the carbon bonded to the hydroxyl group has two neighbors also. So, we have a secondary substrate.

(E)-pent-3-en-2-yl 4-methylbenzenesulfonate

In this case, the leaving group is "OTs" (Tosylate), the carbon bonded to the tosylate group has as a neighbor a double bond. Therefore, we have an allylic substrate.

3a-bromooctahydro-1H-indene

In this molecule, the leaving group is "Br", the carbon bonded to the bromine has three neighbors. So, we have a tertiary substrate.

1-iodo-3-methylbutane

In this molecule, the leaving group is "I", the carbon bonded to the iodide has only one neighbor. So, we have a primary substrate.

See figure 1

I hope it helps!

4 0

3 years ago

How can models demonstrate theories of our expanding universe?​

How can models demonstrate theories of our expanding universe?