You can push the tip of your nose up and it will make it smaller for a small amount of time.
Answer:
932.44 km/s
Explanation:
Given that:
The work function of the magnesium = 2.3 eV
Energy in eV can be converted to energy in J as:
1 eV = 1.6022 × 10⁻¹⁹ J
So, work function =
Using the equation for photoelectric effect as:
Also,
Applying the equation as:
Where,
h is Plank's constant having value
c is the speed of light having value
m is the mass of electron having value
is the wavelength of the light being bombarded
v is the velocity of electron
Given,
Thus, applying values as:
v = 9.3244 × 10⁵ m/s
Also, 1 m = 0.001 km
<u>So, v = 932.44 km/s</u>
To answer the question above, multiply the given number of moles by the molar masses.
(A) (0.20 mole) x (32 g / 1 mole) = 6.4 grams O2
(B) (0.75 mole) x (62 g / 1 mole) = 46.5 grams H2CO3
(C) (3.42 moles) x (28 g / 1 mole) = 95.7 grams CO
(D) (4.1 moles) x (29.88 g / 1 mole) = 122.508 g Li2O
The answer to the question above is letter D.
Answer:
Explanation:
To solve this problem, we must understand the relationship between mass of a substance and the number of atoms.
Atoms are the smallest indivisible particles of any matter. A substance can be made up of several number of atoms in their space.
The mass of any substance is a function of the amount of atoms its contains.
The mass of a substance is related in chemistry to the amount of atoms its contains using the parameter called the number of moles.
A mole is the amount of substance that contains the Avogadro's number of particles. This number is 6.02 x 10²³ particles. The particles here can be protons, neutrons, electrons, atoms e.t.c.
Now,
Number of moles = 
Molar mass of copper = 63.6g/mole
Number of moles =
= 0.03mole
Since 1 mole of a substance contains 6.02 x 10²³atoms
0.03 mole of copper will contain 0.03 x 6.02 x 10²³atoms
= 1.89 x 10²² atoms
He needs to add 1.89 x 10²² atoms to make 2g of the sample.