Answer:
Everything you can hold, taste, or smell is made of matter. Matter makes up everything you can see, including clothes, water, food, plants, and animals. It even makes up some things you cannot see, such as air or the smell of perfume.
Answer:
Answers are given below
Explanation:
Significant figures:
When we add or subtract the values the number of significant figures after decimal in result must be equal to the given measurement having less number of decimal places.
b) 5.45 -2.3
3.2
d) 14.98 + 27,340 + 84.7593
27439.74
When we multiply or divide the values the number of significant figures must be equal to the less number of significant figures in given value.
a) 628 × 342
214776
we will round off this value into 3 significant figures.
215000
c) 28.0/13.483
2.08
Hey there!
1 mol has 6.022 x 10²³ molecules.
If we have 4.2 mol F₂, multiply the number of molecules in 1 mol by 4.2.
4.2 x 6.022 x 10²³
2 sig figs
25 x 10²³
Put this properly into scientific notation.
2.5 x 10²⁴ molecules of F₂
Hope this helps!
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.
The indicator, phenolphthalein is added to the analyte as an indicator in acid–base titrations.
Phenolphthalein is a color changing indicator for acid base titrations.
Titration is a quantitative technique used to find concentration of an unknown solution(analyte ) from a solution of known concentration. which is the titrant.
Now the procedure is set up that, the titrant is in the burette and added to the analyte with known volume)in a conical flask in the presence of an indicator till the endpoint of the reaction.
This is marked by a sharp change of color to explain the point when the titrant neutralizes the analyte solution.(phenolphthalein is colorless in acidic solutions but turns pink in basic solutions).
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