Answer:
1.99 x 10⁻¹⁸J
Explanation:
Given parameters:
Frequency of the wave = 3 x 10¹⁵Hz
Unknown:
Energy of the photon = ?
Solution:
To solve this problem, we use the expression below;
E = hf
Where E is the energy, h is the Planck's constant and f is the frequency
Now insert the parameters and solve for E;
E = 6.63 x 10⁻³⁴ x 3 x 10¹⁵ = 19.9 x 10⁻¹⁹J or 1.99 x 10⁻¹⁸J
Answer:
B. It undergoes a physical change.
Explanation:
Hello there!
In this case, since we know that chemical changes lead to the formation of new atoms and/or compounds due to the bonds rearrangement of the initial substances and the physical changes occur without changing the composition of the initial substances, we can infer that, since melting is a process that changes the phase of matter from solid to liquid without changing the identity of the initial substance, the answer to this question would be B. It undergoes a physical change. because the other options describe chemical changes.
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Answer:
53.6 g of N₂H₄
Explanation:
The begining is in the reaction:
N₂(g) + 2H₂(g) → N₂H₄(l)
We determine the moles of each reactant:
59.20 g / 28.01 g/mol = 2.11 moles of nitrogen
6.750 g / 2.016 g/mol = 3.35 moles of H₂
1 mol of N₂ react to 2 moles of H₂
Our 2.11 moles of N₂ may react to (2.11 . 2) /1 = 4.22 moles of H₂, but we only have 3.35 moles. The hydrogen is the limiting reactant.
2 moles of H₂ produce at 100 % yield, 1 mol of hydrazine
Then, 3.35 moles, may produce (3.35 . 1)/2 = 1.67 moles of N₂H₄
Let's convert the moles to mass:
1.67 mol . 32.05 g/mol = 53.6 g
Answer: Chosen landforms are:
1) Hill
2) Mountain
3) Plateau
4) Valley
Explanation:
1) Hill is an elevated location smaller than a mountain. Location: Land
2) Mountain is a large mass of earth and rock, rising above the common level of the earth or adjacent land, usually given by geographers as above 1000 feet in height (or 304.8 metres).
Location: Land or Water
3) Plateau is a largely level expanse of land at a high elevation. It is also known as tableland.
Location: Land
4) Valley is an elongated depression between hills or mountains, often with a river flowing through it.
Location: Land or Water
The balanced chemical reaction:
C3H8 + 5O2 = 3CO2 + 4H2O
We are given the amount of the carbon dioxide to be produced. This will be the starting point of our calculations.
<span>43.62 L CO2 ( 1 mol CO2 / 22.4 L CO2 ) (5 mol O2 / 3 mol CO2 ) (
22.4 L O2 / 1 mol O2) = 72.7 L O2</span>
