Answer:
False
Explanation:
Roman numerals are seen in the names of several compounds. They often appear immediately after the name of central atom in the molecule.
These Roman numerals are used to depict the oxidation state of the central atom in the molecule and not to show how many of that ion appear in the formula.
For instance, in carbon IV oxide, the Roman numeral IV shows that the central atom in the compound-carbon is in the +4 oxidation state.
Answer: d Positive particles in the nucleus are attracted to shared electrons, so the atoms stay close together.
Explanation:
Answer:
two oxygen atoms
Explanation:
One mole of oxygen gas, which has the formula O2, has a mass of 32 g and contains 6.02 X 1023 molecules of oxygen but 12.04 X 1023 (2 X 6.02 X 1023) atoms, because each molecule of oxygen contains two oxygen atoms.
Answer:
The true stress required = 379 MPa
Explanation:
True Stress is the ratio of the internal resistive force to the instantaneous cross-sectional area of the specimen. True Strain is the natural log to the extended length after which load applied to the original length. The cold working stress – strain curve relation is as follows,
σ(t) = K (ε(t))ⁿ, σ(t) is the true stress, ε(t) is the true strain, K is the strength coefficient and n is the strain hardening exponent
True strain is given by
Epsilon t =㏑ (l/l₀)
Substitute㏑(l/l₀) for ε(t)
σ(t) = K(㏑(l/l₀))ⁿ
Given values l₀ = 49.7mm, l =51.7mm , n =0.2 , σ(t) =379Mpa
379 x 10⁶ = K (㏑(51.7/49.7))^0.2
K = 379 x 10⁶/(㏑(51.7/49.7))^0.2
K = 723.48 MPa
Knowing the constant value would be same as the same material is being used in the second test, we can find out the true stress using the above formula replacing the value of the constant.
σ(t) = K(㏑(l/l₀))ⁿ
l₀ = 49.7mm, l = 51.7mm, n = 0.2, K = 723.48Mpa
σ(t) = 723.48 x 106 x (㏑(51.7/49.7))^0.2
σ(t) = 379 MPa
The true stress necessary to plastically elongate the specimen is 379 MPa.
“Red sky at night, sailors delight. Red sky in morning, sailors take warning.”
A reddish sunset means that the air is dusty and dry. Since weather in North American latitudes usually moves from west to east, a red sky at sunset means dry weather—good for sailing—is moving east. Conversely, a reddish sunrise means that dry air from the west has already passed over us on their way easy, clearing the way for a storm to move in.
“Clear Moon, frost soon.”
When the night sky is clear, Earth’s surface cools rapidly—there is no cloud cover to keep the heat in. If the night is clear enough to see the Moon and the temperature drops enough, frost will form. Expect a chilly morning!
“Ring around the moon? Rain real soon.”
A ring around the moon usually indicates an advancing warm front, which means precipitation. Under those conditions, high, thin clouds get lower and thicker as they pass over the moon. Ice crystals are reflected by the moon’s light, causing a halo to appear.
“Rain foretold, long last. Short notice, soon will pass.”
If you find yourself toting an umbrella around for days “just in case,” rain will stick around for several hours when it finally comes. The gray overcast dominating the horizon means a large area is affected. Conversely, if you get caught in a surprise shower, it’s likely to be short-lived.
“The higher the clouds, the finer the weather.”
If you spot wispy, thin clouds up where jet airplanes fly, expect a spell of pleasant weather.
Keep an eye, however, on the smaller puff clouds (cumulus), especially if it’s in the morning or early afternoon. If the rounded tops of these clouds, which have flat bases, grow higher than the one cloud’s width, then there’s a chance of a thunderstorm forming.
