Answer:
An atom is made of up subatomic particles called protons, neutrons and electrons. The center of an atom is called the nucleus and is where the protons and neutrons are held while electrons orbit the nucleus in orbital shells. A electron has a negative charge, a proton has a positive charge, and a neutron has no charge (neutral).
The atomic number of a atom is the total amount of the atom's protons. In a neutral atom (Not an ion), the amount of electrons is the same as the protons. Therefore, the atomic number also tells the amount of electrons in the atom.
A ion is a negatively or positively charged particle due to the giving or taking of electrons with one or more atoms (Called an ionic bond). An atom that gives away electrons becomes positively charge because that atom now has more protons than neutrons. An atom that takes an electron becomes negatively charge because that atom now has more electrons than protons.
Atomic Mass is the sum of an atom proton and neutrons. To determine how many neutron an atom has, subtract the atomic mass from the atomic number. Electrons do not play a part in atomic mass as their mass is 1/1,836 of a proton's mass.
A isotope is two or more forms of the same element that contain equal amounts of protons but different amount of neutrons.
Answer:
(c) The retention time would be higher (d) The retention time would be lower.
Explanation:
For the polar solutes which were separated using the hydrophilic interaction chromatography (HILIC) with a strongly polar bonded phase, the retention time would be higher if eluent were changed from 80 vol% to 90 vol% acetonitrile in water.
However, for the polar solutes which were separated using the normal-phase chromatography on bare silica with methyl t=butyl ether and 2-propanol solvent, the retention time would be lower if the eluent were changed from 40 vol% to 60 vol% 2-propanol.
Answer:
Volume = 45.62L
Explanation:
Data;
V1 = 54.9L
T1 = 64°C = (64 + 273.15)k = 337.15K
T2 = 7°C = (7 + 273.15)k = 280.15K
V2 = ?
From Charles law,
The volume of a fixed mass of gas is directly proportional to its temperature provided that pressure remains constant
V = KT, K = V / T = V1 / T1 = V2 / T2 = V3 / T3 =.........= Vn / Tn
(54.9 / 337.15) = (V2 / 280.15)
V2 = (54.9 * 280.15) / 337.15
V2 = 45.618L
V2 = 45.62L
Answer: Significant figures in a measurement are all measured digits, and one estimated digit
Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements.
Explanation:
Significant figures : The figures in a number which express the value or the magnitude of a quantity to a specific degree of accuracy or precision is known as significant digits.
The significant figures of a measured quantity are defined as all the digits known with certainty and the first uncertain or estimated digit.
Rules for significant figures:
1. Digits from 1 to 9 are always significant and have infinite number of significant figures.
2. All non-zero numbers are always significant.
3. All zero’s between integers are always significant.
4. All zero’s preceding the first integers are never significant.
5. All zero’s after the decimal point are always significant.