Concept explainers
a)
Interpretation:The mass of sulfur in the galena sample is to be calculated.
Concept introduction:Law of conservation of mass states that in an isolated system mass of system must remain constant over time that means system’s quantity can neither be added or nor be removed.
In a sample or a mixture, the mass fraction is mass of one substance divided by the mass of the total sample or mixture.
The mass percentageis calculated as the mass of a substance divided by the total mass of the sample, multiplied by
b)
Interpretation: The mass fraction of lead and sulfur in the galena sample should be calculated.
Concept introduction: Law of conservation of mass states that in an isolated system mass of system must remain constant over time that means system’s quantity can neither be added or nor be removed.
In a sample or a mixture, the mass fraction is mass of one substance divided by the mass of the total sample or mixture.
The mass percentage is calculated as the mass of a substance divided by the total mass of the sample, multiplied by
c)
Interpretation: The mass percent of lead and sulfur in the galena sample should be calculated.
Concept introduction: Law of conservation of mass states that in an isolated system mass of the system must remain constant over time that means the system’s quantity can neither be added or nor be removed.
In a sample or a mixture, the mass fraction is mass of one substance divided by the mass of the total sample or mixture.
The mass percentage is calculated as the mass of a substance divided by the total mass of the sample, multiplied by
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Principles of General Chemistry
- Two basic laws of chemistry are the law of conservation of mass and the law of constant composition. Which of these laws (if any) do the following statements illustrate? (a) Lavoisier found that when mercury(ll) oxide, HgO, decomposes, the total mass of mercury (Hg) and oxygen formed equals the mass of mercury(ll) oxide decomposed. (b) Analysis of the calcium carbonate found in the marble mined in Carrara, Italy, and in the stalactites of the Carlsbad Caverns in New Mexico gives the same value for the percentage of calcium in calcium carbonate. (c) Hydrogen occurs as a mixture of two isotopes, one of which is twice as heavy as the other.arrow_forwardThe present average concentration (mass percent) of magnesium ions in seawater is 0.13%. A chemistry textbook estimates that if 1.00 × 108 tons Mg were taken out of the sea each year, it would take one million years for the Mg concentration to drop to 0.12%. Do sufficient calculations to either verify or refute this statement. Assume that Earth is a sphere with a diameter of 8000 mi, 67% of which is covered by oceans to a depth of 1 mi, and that no Mg is washed back into the oceans at any time.arrow_forwardThe element bromine is Br2, so the mass of a Br2 molecule is the sum of the mass of its two atoms. Bromine has two isotopes. The mass spectrum of Br2 produces three peaks with relative masses of 157.836, 159.834, and 161.832, and relative heights of 6.337, 12.499. and 6.164, respectively. (a) What isotopes of bromine are present in each of the three peaks? (b) What is the mass of each bromine isotope? (c) What is the average atomic mass of bromine? (d) What is the abundance of each of the two bromine isotopes?arrow_forward
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- Obtain an estimate for the number of atoms in the universe. Make the following assumptions: (a) All of the atoms in the universe are hydrogen atoms in stars. (This is not a ridiculous assumption because over threefourths of the atoms in the universe are in fact hydrogen. Gas and dust between the stars represent only about 15% of the visible matter of our galaxy, and planets compose a far smaller fraction.) (b) The sun is a typical star composed of pure hydrogen with a density of 1.4 g/cm^3 and a radius of 7x10^8 m. (c) Each of the roughly 100 billion stars in the Milky Way galaxy contains the same number of atoms as our sun. (d) Each of the 10 billion galaxies in the visible universe contains the same number of atoms as our Milky Way galaxy.arrow_forwardGive the chemical formula for (a) chlorite ion, (b) chlorideion, (c) chlorate ion, (d) perchlorate ion, (e) hypochlorite ion.arrow_forwardFormula mass of H20 3D | (2 Н atoms) * (1.01 aти)) + (10 atoт) * (16.00 ати)] — 18. 02 ати Water (H2O) has two H atoms, so the atomic mass of one H atom (found on the periodic table) must be multiplied by two. As only one oxygen atom is in the compound, the atomic mass of an O atom is multiplied by the number one. Let's look at a slightly more difficult example. Take a minute and calculate the formula mass of the compound, aluminum carbonate, Al2(CO3)3, in the box below. Show all of your work. Show work here:arrow_forward
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