Scientific questions and hypotheses come up frequently while one is engaged in investigating a scientific phenomenon such as natural geological phenomena as may occur in geological mapping in the field. For example, there may be a question does this canyon or deeply incised valley which is quite straight follow a weakness in the earth's crust like a major fault or the direction of bedding in well bedded sedimentary rocks. In a particular topographic area, some hypotheses which may be developed is that valleys follow geological structure whereas ridges follow resistant rocks like quartzites or quartz sandstones or in the ocean, points or capes may represent resistant quartz sandstones and bays may represent weak soft shales recessively weathering
Answer:
0.846 moles.
Explanation:
- This is a stichiometric problem.
- The balanced equation of complete combustion of butane is:
C₄H₁₀ + 6.5 O₂ → 4 CO₂ + 5 H₂O
- It is clear from the stichiometry of the balanced equation that complete combustion of 1.0 mole of butane needs 6.5 moles of O₂ to produce 4 moles of CO₂ and 5 moles of H₂O.
<u><em>Using cross multiplication:</em></u>
- 1.0 mole of C₄H₁₀ reacts with → 6.5 moles of O₂
- ??? moles of C₄H₁₀ are needed to react with → 5.5 moles of O₂
- The number of moles of C₄H₁₀ that are needed to react with 5.5 moles of O₂ = (1.0 x 5.5 moles of O₂) / (6.5 moles of O₂) = 0.846 moles.
atomic mass=percentage of isotope a * mass of isotope a + percentage of isotope b * mass of isotope b+...+percentage of isotope n * mass of isotope n.
Data:
mass of isotope₁=267.8 u
percentage of isotope₁=90.3%
mass of isotope₂=270.9 u
percentage of isotope₂=9.7%
Therefore:
atomic mass=(0.903)(267.8 u)+(0.097)(270.9 u)=
=241.8234 u + 26.2773 u≈268.1 u
Answer: the mass atomic of this element would be 268.1 u
