Answer:
Explanation:
Energy of falling radiation having wavelength of 265 nm
= h c / λ where h is plank's constant , c is velocity of light and λ is wavelength of radiation . Putting the values
Energy of light photon = 6.6 x 10⁻³⁴ x 3 x 10⁸ / 265 x 10⁻⁹
= .0747 x 10⁻¹⁷
= 7.47 x 10⁻¹⁹ J .
Work function of sodium is 4.41 x 10⁻¹⁹
So kinetic energy of ejected electron = energy of falling photon - work function
= 7.47 x 10⁻¹⁹ - 4.41 x 10⁻¹⁹
= 3.06 x 10⁻¹⁹ eV .
Given 450.98 g of Cu(NO3)2, how many moles of Ag can be made? Provide your final answer rounded to two decimal places.
Cu + 2 AgNO3 → Cu(NO3)2 + 2 Ag
Answer:
4.82 moles of Ag.
Explanation:
We'll begin by calculating the number of mole in 450.98 g of Cu(NO₃)₂. This can be obtained as follow:
Molar mass of Cu(NO₃)₂ = 63.5 + 2[14 + (16×3)]
= 63.5 + 2[14 + 48]
= 63.5 + 2[62]
= 63.5 + 124
= 187.5 g/mol
Mass of Cu(NO₃)₂ = 450.98 g
Mole of Cu(NO₃)₂ =?
Mole = mass /Molar mass
Mole of Cu(NO₃)₂ = 450.98 / 187.5
Mole of Cu(NO₃)₂ = 2.41 moles
Next, we shall determine the number of mole of Cu needed to produce 450.98 g (i.e 2.41 moles) of Cu(NO₃)₂. This can be obtained as follow:
Cu + 2AgNO₃ —> Cu(NO₃)₂ + 2Ag
From the balanced equation above,
1 mole of Cu reacted to produce 1 mole of Cu(NO₃)₂.
Therefore, 2.41 moles of Cu will also react to produce 2.41 moles of Cu(NO₃)₂.
Thus, 2.41 moles of Cu is needed for the reaction.
Finally, we shall determine the number of mole of Ag produced from the reaction. This can be obtained as follow:
From the balanced equation above,
1 mole of Cu reacted to produce 2 moles of Ag.
Therefore, 2.41 moles of Cu will react to produce = 2× 2.41 = 4.82 moles of Ag.
Thus, 4.82 moles of Ag were obtained from the reaction.
18. What is one of the three things that cause the surface currents of the oceans?
A.differences in salinity
B.temperature differences
C. density differences
D. Coriolis effect
Answer:
b. temperature difference
Vitamin C is a covalent compound with the molecular
formula C6H8O6. The recommended daily dietary
allowance of vitamin C for children aged 4-8 years is
0.000142mol. What is the mass of this allowance in grams?
The mass allowance of Vitamin C for children aged 4-8 years is equal to 0.025 grams.
What is a mole?A mole can be defined as a standard unit that can be utilized to evaluate the number of entities such as atoms, molecules, ions, or other particular particles in a particular amount of the substance.
The number of elementary entities present in one mole of any chemical substance was found to be equal to 6.023 × 10²³ which is also known as the Avogadro number.
Given, the number of moles of vitamin C = 0.000142 moles
Given, the molecular formula of Vitamin C is C₆H₈O₆.
The mass of one mole of C₆H₈O₆ = 176 g
One mole of Vitamin C has mass = 176 g
0.000142 mol of Vitamin C has mass = 0.000142×176 = 0.025 g
Therefore, the mass of 0.000142 mol of Vitamin C is 0.025 g.
Learn more about the mole, here:
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Heat will continue to move until the objects or areas have reached the same ______.
Answer: Thermal Equilibrium
Explanation:
Answer:
temperature
Explanation:
I think that's it i'm sorry if i'm wrong