Chemistry ch2 homework
Consider two compounds. Compound A contains 15.7 g of sulfur and 18.6 g of fluorine. Compound B contains 25.4 g of sulfur and 60.2 g of fluorine. What is the mass ratio of fluorine to sulfur in Compound A
1.18g
How many chlorine atoms are in 35 molecules of chloroform, CHCl₃?
105
In an experiment, the reaction of 100.0 g of iodine produced 144.9 g of a compound formed from iodine and fluorine. Given that the mass ratio of iodine to fluorine is 2.23, what is the mass in grams of this compound would be expected to form in the same experiment if you started with 85.2 g of iodine?
123.4g
The chemical formula of caffeine is C₈H₁₀N₄O₂. How many N atoms are in 4 molecules of caffeine?
16
There are three isotopes of an element, X-28, X-29, and X-30, with relative abundances of 92.2297%, 4.6832%, 3.0872%, respectively. How many neutrons are in an atom of silicon-30?
16
Given the following chemical symbol, answer the questions below. This atom has 70 electrons and 114 neutrons. What value should Y be?
190
In an experiment, the reaction of 100.0 g of iodine produced 144.9 g of a compound formed from iodine and fluorine. What is the mass ratio of iodine to fluorine in the compound
2.23
Consider two compounds. Compound A contains 15.7 g of sulfur and 18.6 g of fluorine. Compound B contains 25.4 g of sulfur and 60.2 g of fluorine. What is the mass ratio of fluorine to sulfur in Compound B?
2.37g
A blood sample of 2.29 milliliters is collected from a patient to be analyzed for a platelet count. Human blood should have around 1.04 kg/L platelets. What is the expected mass in grams of platelets in the blood sample?
2.38g
The mass of a piece of metal is 20.7651 grams. When the piece of metal was dropped into a graduated cylinder that had an initial water volume of 5.35 cm³, the total volume was 13.34 cm³. What is the density of the piece of metal in g/cm³?
2.60 g/cm3
How many oxygen atoms are in 25 molecules of tetraphosphorus decoxide (also known as phosphorus pentoxide), P₄O₁₀?
250
There are three isotopes of an element, X-28, X-29, and X-30, with relative abundances of 92.2297%, 4.6832%, 3.0872%, respectively. What is the average atomic mass in amu of this element using four significant figures?
28.11 amu
In an experiment, the reaction of 100.0 g of iodine produced 144.9 g of a compound formed from iodine and fluorine. What mass of fluorine was consumed in the reaction?
44.9g
Determine the molar mass of C₂H₇N.
45.10 g/mol
There are two naturally occurring isotopes of europium, ¹⁵¹Eu (151.0 amu) and ¹⁵³Eu (153.0 amu). If the atomic mass of Eu is 151.96, what is the approximate natural abundance of ¹⁵¹Eu?
50%
An unknown element is a mixture of isotopes ¹²⁰X and ¹²²X. The average atomic mass of X is 121.03 amu. What is the percent abundance of ¹²²X?
51.5%
An unknown element X has the following isotopes: ⁵²X (83.50% abundant), ⁴⁹X (8.00% abundant), ⁵⁰X (8.50% abundant). What is the average atomic mass in amu of X?
51.6 amu
An atom of the isotope ¹³³Cs contains how many protons (p), neutrons (n), and electrons (e)?
55 p, 78 n, 55 e
Given the following chemical symbol, answer the questions below. This atom has 70 electrons and 114 neutrons. What value should Z be?
6
Determine the molar mass of Li₂CO₃
73.89
For each set of chemical symbols, determine the species that fit the category listed. Which of the species shown have the same number of electrons? A:128 Te 2- B: 134 La+ C: 134 Cs D: 131 Xe
A & D
For each set of chemical symbols, determine the species that fit the category listed. Which of the species shown has the largest number of protons? A:128 Te 2- B: 134 La+ C: 134 Cs D: 131 Xe
B
Which of the following statements about subatomic particles are false? A. Neutrons reside inside of the nucleus. B. The atomic cumber is equal to the number of neutrons in the nucleus of an atom. C. Electrons are more massive than protons.
B & C
For each set of chemical symbols, determine the species that fit the category listed. Which of the species shown have the same number of neutrons? A:128 Te 2- B: 134 La+ C: 134 Cs D: 131 Xe
B & D
Polystyrene is made up of a series of styrene (C₈H₈) monomer units. What is the empirical formula for styrene?
CH
Consider two compounds. Compound A contains 15.7 g of sulfur and 18.6 g of fluorine. Compound B contains 25.4 g of sulfur and 60.2 g of fluorine. For Compound A, the ratio of fluorine to sulfur is 1.18. For Compound B, the ratio of fluorine to sulfur is 2.37. Using the Law of Definite Proportions (also called the Law of Constant Composition), could Compound A and Compound B be the same compound?
D) No, because they have different ratios of the same elements.
Given the following chemical symbol, answer the questions below. What should go in place of X?
Os
There are three isotopes of an element, X-28, X-29, and X-30, with relative abundances of 92.2297%, 4.6832%, 3.0872%, respectively. Which element is this?
Si - Silicon( the mass of 28.11 is closest to the mass of Si)
The atomic mass of germanium (Ge) on the periodic table is 72.630 amu. Which of the following best explains why the atomic mass is a fraction between 72 and 73?
The presence of different isotopes
Rutherford's gold foil experiment determined that
most of the space in an atom is empty except for a concentrated area called the nucleus
Given the following chemical symbol, answer the questions below. What group is this element part of?
the transition metals
