Answer:
4 significant figures
Explanation:
Significant figures are the units/digits within a number that make the number more accurate and precise.
All digits (except for 0) are always significant. Therefore, all the digits in 43.55 are significant. Since there are 4 digits in the given number, there are 4 significant figures.
Answer: option D - The total number of nucleons changes.
Explanation:
Nuclear Reaction is best described as a process such as the fission of an atomic nucleus, or the fusion of one or more atomic nuclei and / or subatomic particles in which the NUMBER of PROTONS and / or NEUTRONS in a nucleus CHANGES; the reaction products may contain a different element or a different isotope of the same element.
Note that the NUCLEONS refers to ONE of the subatomic particles of the atomic nucleus, i.e. a PROTON or a NEUTRON.
So, in a Nuclear reaction, the total number of nucleons changes.
P₄O₁₀ + 6H₂O → 4H₃PO₄
The equation shows us that the molar ratio of
P₄O₁₀ : 6H₂O = 1:6
We also know that one mole of a substance contains 6.02 x 10²³ particles. We can use this to calculate the moles of water.
moles(H₂O) = (5.51 x 10²³) / (6.02 x 10²³)
= 0.92 mole
That means moles of P₄O₁₀ = 0.92 / 6
= 0.15
Each mole of P₄O₁₀ contains 4 moles of P.
moles(P) = 4 x 0.15 = 0.6 mol
Mr of P = 207 grams per mol
Mass of P = 207 x 0.6
= 124.2 grams
The combination of seatbelts and airbags can reduce the risk of death in a collision by up to 80%.
The seatbelts help to keep the person in one position and prevent impact with the vehicle as the vehicle comes to a sudden stop. Moreover, the airbag increases the time of collision to reduce the impact experienced by the person. An increased time of collision greatly reduces the damage that is done to the body.
