Answer:
16.0%.
Explanation:
Volume percent of a substance is the ratio of the substance volume to the solution volume multiplied by 100.
V % of ethanol = (volume of ethanol / volume of the solution) x 100.
volume of ethanol = 90.0 mL, volume of the solution = 550.0 mL.
∴ V % of ethanol = (90.0 mL / 550.0 mL) x 100 = 16.36% ≅ 16.0%.
Answer:
The Mitochondria
Explanation:
Mitochondria are membrane-bound cell organelles that generate most of the energy required to power the cell's organic chemistry reactions. Energy created by the mitochondria is kept in a tiny molecule known as adenosine triphosphate (ATP).
Answer:
obsidian
Explanation:
because it is an igneous rock which is smooth
We write DE = q+w, where DE is the internal energy change and q and w are heat and work, respectively.
(b)Under what conditions will the quantities q and w be negative numbers?
q is negative when heat flows from the system to the surroundings, and w is negative when the system does work on the surroundings.
As an aside: In applying the first law, do we need to measure the internal energy of a system? Explain.
The absolute internal energy of a system cannot be measured, at least in any practical sense. The internal energy encompasses the kinetic energy of all moving particles in the system, including subatomic particles, as well as the electrostatic potential energies between all these particles. We can measure the change in internal energy (DE) as the result of a chemical or physical change, but we cannot determine the absolute internal energy of either the initial or the final state. The first law allows us to calculate the change in internal energy during a transformation by calculating the heat and work exchanged between the system and its surroundings.
