Explanation:
(a) The mass of an object remains the same always. It is independent of its location. In this case, an iron nail is ground into powder. It means that its mass will remain unchanged. Hence, (a) is the correct option.
(b) Whenever there is a change of color of an object, a chemical reaction occurs. It shows that a reaction happens there. In this problem, a paper turns yellow-brown upon exposure to sunlight. A chemical reaction takes place there. Hence, (b) is the correct option.
Answer:
Composition of the mixture:
%
%
Composition of the vapor mixture:
%
%
Explanation:
If the ideal solution model is assumed, and the vapor phase is modeled as an ideal gas, the vapor pressure of a binary mixture with
and
molar fractions can be calculated as:

Where
and
are the vapor pressures of the pure compounds. A substance boils when its vapor pressure is equal to the pressure under it is; so it boils when
. When the pressure is 0.60 atm, the vapor pressure has to be the same if the mixture is boiling, so:

With the same assumptions, the vapor mixture may obey to the equation:
, where P is the total pressure and y is the fraction in the vapor phase, so:
%
The fractions of B can be calculated according to the fact that the sum of the molar fractions is equal to 1.
Answer:
its d, forming a hypothesis is always one of the first things you do, and d is the best answer from these 4
Answer:
<u>The same as</u> can best fill the space
Explanation:
The law of conservation of mass states that matter cannot be created or destroyed in a chemical reaction. For example, when wood burns, the mass of the soot, ashes, and gases, equals the original mass of the charcoal and the oxygen when it first reacted.
It shows that when wood burns, it combines with oxygen and changes not only to ashes, but also to carbon dioxide and water vapor. The gases float off into the air, leaving behind just the ashes. Suppose you had measured the mass of the wood before it burned and the mass of the ashes after it burned. Also suppose you had been able to measure the oxygen used by the fire and the gases produced by the fire. What would you find? The total mass of matter after the fire would be the same as the total mass of matter before the burning.
In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chromosomes as the original parent cell. The two meiotic divisions are known as meiosis I and meiosis II.
Explanation: