
Concept explainers
(a)
Interpretation:
Whether the statement “a sample of potassium chloride from Chile contains the same percent by mass of potassium as one from Poland” obeys the law of mass conservation, the law of definite composition or the law of multiple proportions is to be determined.
Concept introduction:
The law of mass conservation - Introduced by the famous French chemist Antoine Lavoisier, the law states that there is no change in the total mass of the substances that go into any physical or
The law of definite composition - This law can be defined as; a particular compound maintains an exact universal proportion of elements in its composition, irrespective of the source. The proposal for this law was made by Joseph Proust.
The multiple proportions law - The ratio of the weights of an element with variable mass is small whole numbers when it forms more than one compound by combining with an element with fixed weight.
(a)

Answer to Problem 2.14P
The statement “a sample of potassium chloride from Chile contains the same percent by mass of potassium as one from Poland” obeys the law of definite composition.
Explanation of Solution
The law of definite composition explains that a compound is formed upon the
The molecular formula for
The statement “a sample of potassium chloride from Chile contains the same percent by mass of potassium as one from Poland” obeys the law of definite composition due to the presence of one ion each of potassium and chloride in samples obtained from different sources.
(b)
Interpretation:
Whether the statement “a flashbulb contains magnesium and oxygen before use and magnesium oxide afterward, but its mass does not change”obeys the law of mass conservation, law of definite composition or the law of multiple proportions is to be determined.
Concept introduction:
The law of mass conservation - Introduced by the famous French chemist Antoine Lavoisier, the law states that there is no change in the total mass of the substances that go into any physical or chemical reaction.
The law of definite composition - This law can be defined as; a particular compound maintains an exact universal proportion of elements in its composition, irrespective of the source. The proposal for this law was made by Joseph Proust.
The multiple proportions law - The ratio of the weights of an element with variable mass is small whole numbers when it forms more than one compound by combining with an element with fixed weight.
(b)

Answer to Problem 2.14P
The statement “a flashbulb contains magnesium and oxygen before use and magnesium oxide afterward, but its mass does not change” obeys the law of mass conservation.
Explanation of Solution
The reaction for the formation of a molecule of magnesium oxide is as follows:
The equation shows the presence of two atoms of magnesium on each side of the equation. There are two atoms of oxygen on each side of the equation as well. The total mass of the reactants and products can be calculated as follows:
From the calculations above, the observation can be made that the total mass of the reactant is equal to that of the product.
The statement “a flashbulb contains magnesium and oxygen before use and magnesium oxide afterward, but its mass does not change” obeys the law of mass conservation. The comparisons made by calculating the total mass of reactants and products prove it.
(c)
Interpretation:
Whether the statement “arsenic and oxygen form one compound that is
Concept introduction:
The law of mass conservation - Introduced by the famous French chemist Antoine Lavoisier, the law states that there is no change in the total mass of the substances that go into any physical or chemical reaction.
The law of definite composition - This law can be defined as; a particular compound maintains an exact universal proportion of elements in its composition, irrespective of the source. The proposal for this law was made by Joseph Proust.
The multiple proportions law - The ratio of the weights of an element with variable mass is small whole numbers when it forms more than one compound by combining with an element with fixed weight.
The mass fraction of an element in a compound is defined as the ratio of the sum of the masses of all the atoms of that element to that of the mass of one mole of compound.
Mass percent of an element represents the percentage concentration of that element in a compound. It is equal to the mass fraction expressed as a percentage. The general formula to calculate the mass percent of an element A in a compound is as follows:
(c)

Answer to Problem 2.14P
The statement “arsenic and oxygen form one compound that is
Explanation of Solution
The two compounds arsenic formed by the combination of arsenic and oxygen atoms are
The total mass of
Substitute
The mass of arsenic
Substitute 2 for number of atoms of
The formula to calculate the mass percent of arsenic in
Substitute
The total mass of
Substitute
The formula to calculate the mass percent of arsenic in
Substitute
The number of atoms of arsenic being constant in both the compounds, the arsenic atoms combines with oxygen atoms whose proportions are different in both the compounds.
The total mass of oxygen atoms in compound
The statement “arsenic and oxygen form one compound that is
Want to see more full solutions like this?
Chapter 2 Solutions
Chemistry: The Molecular Nature of Matter and Change
- Using a cell of known pathlength b = 1.25115 x 10-3 cm, a water absorption spectrum was measured. The band at 1645 cm-1, assigned to the O-H bending, showed an absorbance, A, of 1.40. a) Assuming that water density is 1.00 g/mL, calculate the water molar concentration c (hint: M= mole/L) b) Calculate the molar absorptivity, a, of the 1645 cm-1 band c) The transmitted light, I, can be written as I= Ioexp(-xb), where x is the absorption coefficient (sometimes designated as alpha), Io is the input light, and b is the cell pathlength. Prove that x= (ln10)*x*c. (Please provide a full derivation of the equation for x from the equation for I). d) Calculate x for the 1645 cm-1 bandarrow_forwardI need help with the follloaingarrow_forwardFor a CARS experiment on a Raman band 918 cm-1, if omega1= 1280 nm, calculate the omega2 in wavelength (nm) and the CARS output in wavelength (nm).arrow_forward
- I need help with the following questionarrow_forwardFor CARS, which statement is not true regarding its advantages? a) Contrast signal based on vibrational characteristics, no need for fluorescent tagging. b) Stronger signals than spontaneous Raman. c) Suffers from fluorescence interference, because CARS signal is at high frequency. d) Faster, more efficient imaging for real-time analysis. e) Higher resolution than spontaneous Raman microscopy.arrow_forwardDraw the major product of the Claisen condensation reaction between two molecules of this ester. Ignore inorganic byproducts. Incorrect, 5 attempts remaining 1. NaOCH3/CH3OH 2. Acidic workup Select to Draw O Incorrect, 5 attempts remaining The total number of carbons in the parent chain is incorrect. Review the reaction conditions including starting materials and/or intermediate structures and recount the number of carbon atoms in the parent chain of your structure. OKarrow_forward
- Using a cell of known pathlength b = 1.25115 x 10-3 cm, a water absorption spectrum was measured. The band at 1645 cm-1, assigned to the O-H bending, showed an absorbance, A, of 1.40. a) Assuming that water density is 1.00 g/mL, calculate the water molar concentration c (hint: M= mole/L) b) Calculate the molar absorptivity, a, of the 1645 cm-1 band c) The transmitted light, I, can be written as I= Ioexp(-xb), where x is the absorption coefficient (sometimes designated as alpha), Io is the input light, and b is the cell pathlength. Prove that x= (ln10)*x*c d) Calculate x for the 1645 cm-1 bandarrow_forwardConvert 1.38 eV into wavelength (nm) and wavenumber (cm-1) (c = 2.998 x 108 m/s; h = 6.626 x 10-34 J*s).arrow_forwardCan you help me understand the CBC method on metal bridging by looking at this problem?arrow_forward
- A partir de Aluminio y Co(NO3)2ꞏ6H2O, indicar las reacciones a realizar para obtener Azul de Thenard (Al2CoO4).arrow_forwardTo obtain Thenard Blue (Al2CoO4), the following reaction is correct (performed in an oven):Al(OH)3 + Co(OH)2 → Al2CoO4 + 4 H2Oarrow_forwardProblem 38 can u explain and solve thanks april 24arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistryChemistryISBN:9781259911156Author:Raymond Chang Dr., Jason Overby ProfessorPublisher:McGraw-Hill EducationPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
- Organic ChemistryChemistryISBN:9780078021558Author:Janice Gorzynski Smith Dr.Publisher:McGraw-Hill EducationChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningElementary Principles of Chemical Processes, Bind...ChemistryISBN:9781118431221Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. BullardPublisher:WILEY





