Answer:
3.14
Explanation:
A student was comparing two samples with an equal number of carbon atoms. One sample contained only Carbon-12 atoms. One sample contained only Carbon-14 atoms, which contain two more neutrons than Carbon-12 atoms. The student measured the mass of each sample and testing the reactivity of each sample.
Required:
What would best describe the results of the investigation?
Answer:
a) 210 mL of 95% ethanol
b) 75 mL of water
Explanation:
a) We can use the dilution equation to solve this problem. C₁ and V₁ are the concentration and volume of the stock solution, respectively, while C₂ and V₂ are the concentration and volume of the diluted solution.
C₁V₁ = C₂V₂
We want to find V₁, the volume of ethanol stock we need to dilute to prepare the final solution:
V₁ = (C₂V₂) / C₁
The concentrations are represented in percentages. We substitute in the known values to calculate V₁. The units cancel to leave us with units of mL.
V₁ = (C₂V₂) / C₁ = (70%)(285mL) / (95%) = 210 mL
b) The final solution volume is 285 mL and we have added 210 mL of ethanol, so the remaining volume is from the water that we add:
(285 mL - 210 mL) = 75 mL
A vestigial structure is a feature of an organism's body that was once an adaptation shaped by natural selection, but which is no longer useful in their current environment. For example, some species of fish that live in completely dark caves have eyes, although their eyes cannot see and serve no function.
You encounter tasks that would need many peoples help and communicative skills
Most plants are called autotrophs they make their own food