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3 years ago

During a lunar eclipse, the moon appears to be darkened because _______________ is casting a shadow on it.

Chemistry

1 answer:

stealth61 [152]3 years ago

4 0

Answer:

the earth

Explanation:

because the moon is blocking the light of the sun

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Which of these equations are balanced

gogolik [260]

Answer:

Post the equations for help :)

Explanation:

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3 years ago

How do knowing the half-life of carbon 14 can tell scientists the absolute age of a rock sample

katrin [286]

Carbon 14 dating makes some assumptions that are not exactly true, but likely close enough for most purposes. 1 that the ratio of carbon 13 to carbon 14 in Earth's atmosphere has not changed over the last million years. 2 that living things give zero preference to carbon 13 over carbon 14.
3 Carbon 14 dating is often unreliable for rocks which have low carbon content, such as quartz, and some other assumptions.

7 0

3 years ago

4.) The temperature of solid silver increases from 30C to 40C by the addition of 117.5

Artyom0805 [142]

Answer:

The mass of silver is 49 g (0.049 kg).

Explanation:

Initial temperature = $30^{o}$ C

Final temperature = $40^{o}$ C

Quantity of heat required = 117.5 J

Specific heat capacity of silver = 0.240 J/g $^{o} C$

mass of the silver can be determined by;

Q = mcΔθ

Where: Q is the quantity of heat required, m is the mass of substance, c is the specific heat capacity of the substance and Δθ is the change in temperature.

So that,

117.5 = m x 0.240 x (40 - 30)

117.5 = m x 0.24 x 10

= 2.4m

m = $\frac{117.5}{2.4}$

= 48.9583

m ≅

m = 49 g

The mass of silver is 49 g (0.049 kg).

4 0

3 years ago

What happens to an atom when it gains an electron?

jasenka [17]

I'm pretty sure it becomes an ion! If an atom gains a negative electron, it becomes an ion.

6 0

3 years ago

Read 2 more answers

Fish breathe the dissolved air in water through their gills. Assuming the partial pressures of oxygen and nitrogen in air to be

amid [387]

Answer:

X(O₂) = 0.323

X(N₂) = 0.677

Explanation:

We have the partial pressures of oxygen (O₂) and nitrogen (N₂):

P(O₂) = 0.20 atm

P(N₂) = 0.80 atm

In order to solve the problem, you need the solubilities of each gas in water at 298 K. We can consider 1.3 x 10⁻³ mol/(L atm) for oxygen (O₂) and 6.8 x 10⁻⁴mol/(L atm) for nitrogen (N₂) from the bibliography.

s(O₂) = 1.3 x 10⁻³ mol/(L atm)

s(N₂) = 6.8 x 10⁻⁴mol/(L atm)

So, we calculate the concentration (C) of each gas as the product of its partial pressure (P) and the solubility (s):

C(O₂) = P(O₂) x s(O₂) = 0.20 atm x 1.3 x 10⁻³ mol/(L atm) = 2.6 x 10⁻⁴mol/L

C(N₂) = P(N₂) x s(N₂) = 0.80 atm x 6.8 x 10⁻⁴mol/(L atm) = 5.44 x 10⁻⁴ mol/L

In 1 liter of water, we have the following number of moles (n):

n(O₂) = 2.6 x 10⁻⁴ mol

n(N₂) = 5.44 x 10⁻⁴ mol

Thus, the total number of moles (nt) is calculated as the sum of the number of moles of the gases in the mixture:

nt = n(O₂) + n(N₂) = 2.6 x 10⁻⁴ mol + 5.44 x 10⁻⁴ mol = 8.04 x 10⁻⁴ mol

Finally, the mole fraction of each gas is calculated as the ratio between the number of moles of each gas and the total number of moles:

X(O₂) = n(O₂)/nt = 2.6 x 10⁻⁴ mol/(8.04 x 10⁻⁴ mol) = 0.323

X(N₂) = n(N₂)/nt = 5.44 x 10⁻⁴ mol/(8.04 x 10⁻⁴ mol) = 0.677

5 0

3 years ago