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 .
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.
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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
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.