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3 years ago

Why is DNA known as a double helix?

1 answer:

3 0

The answer is in your question:Two A double helix of DNA is formed when two DNA strands each having a 5’and 3’ end wind around each other. Each of the DNA strands have nucleotides present. The two strands are held by hydrogen bonds.

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Find the density of a gas at STP if it’s molar mass is 112g/mol

AleksandrR [38]

Answer:

D= 5 g/L

Explanation:

M= D x Vm

M is the molar mass = 112g/mol

D is the density

Vm is the molar volume whuch is 22.4L at STP

now substitute;

112 = D x 22.4

D= 112\22.4

D= 5 g/L

5 0

3 years ago

Calculate the nuclear binding energy for 5525mn in megaelectronvolts per nucleon (mev/nucleon).

r-ruslan [8.4K]

To solve this question, let us first calculate how much all the nucleons will weigh when they are apart, that is:
Mass of 25 protons = 25(1.0073) = 25.1825 amu 

Mass of neutrons = (55-25)(1.0087) = 30.261 amu

So, total mass of nucleons = 30.261+25.1825 = 55.4435 amu

Now we subtract the mass of nucleons and mass of the Mn nucleus:
55.4435 - 54.938 = 0.5055 amu

This difference in mass is what we call as the mass defect of a nucleus. Now we calculate the binding energy using the formula:

E=mc^2 

But first convert mass defect in units of SI (kg):
Δm = 0.5055 amu = (0.5055) / (6.022x10^26)
Δm = 8.3942x10^-28 kg

Now applying the formula,
E=Δm c^2
E=(8.3942x10^-28)(3x10^8)^2
E=7.55x10^-11 J

Convert energy from Joules to mev then divide by total number of nucleons (55):

E = 7.55x10^-11 J * (6.242x10^12 mev / 1 J) / 55 nucleons

E = 8.57 mev / nucleon

8 0

3 years ago

7-¿Cuántos moles de CO2 estarán encerrados en un recipiente metálico a una presión de 1.10 Atm. y una temperatura de 31 °C, sabi

Aleks [24]

Answer:

7- 0.69 moles.

8- El nuevo volumen es 3.8L.

Explanation:

7- Usando la ley general de los gases:

PV = nRT

PV / RT = n

P es presión = 1.10atm

V es volumen = 15.70L

R es constante de los gases = 0.082atmL/molK

T es temperatura absoluta = 31°C + 273.15K = 304.15K

Reemplazando:

1.10atm*15.70L / 0.082atmL/molK*304.15K = n

<h3>0.69 moles</h3><h3 />

8- La ley combinada de los gases establece como ecuación:

P1V1 / T1 = P2V2 / T2

Donde P1 es la presión inicial = 760mmHg

V1 volumen inicial = 2L

T1 es temperatura absoluta = 273.15 + 27 = 300.15K

P2 = 380mmHg

T2 = 12°C + 273.15 = 285.15K

Reemplazando:

760mmHg*2L / 300.15K = 380mmHg*V2 / 285.15K

3.8L = V2

<h3>El nuevo volumen es 3.8L</h3>

4 0

3 years ago

Why using a temperature probe is preferable to using a conventional mercury thermometers

Crank

This for health and hazard purposes. The conventional thermometers contain mercury which is very dangerous to health. It is toxic which could cause poisoning, respiratory damage and kidney problems. Because of this, it is already illegal to use them for safety purposes. Temperature probes are much safer because they only use thermocouples.

3 0

3 years ago

Why are aldehydes more reactive than ketones?

Simora [160]

Answer:

Aldehydes are typically more reactive than ketones due to the following factors. ... The carbonyl carbon in aldehydes generally has more partial positive charge than in ketones due to the electron-donating nature of alkyl groups. Aldehydes only have one e- donor group while ketones have two.

Explanation:

5 0

3 years ago