About 95% of the mass came from 235U whose mass is 235.0439 amu. Since the rest is coming from an isotope with a higher mass, the average atomic mass should be greater than 235.0439 amu.
Average atomic mass refers to the weighted atomic mass of an element.
Weighted average atomic mass is the sum of (fractional abundance × mass of the isotope) for all isotopes.
Looks like you used the 235 amu and 238 amu as the masses of the isotopes while calculating the weighted average. You must use the exact masses, 235.0439 amu and 238.0508 amu.
Weighted average atomic mass is the sum of (fractional abundance × mass of the isotope) for all isotopes.
The percent abundance of 238U in the sample = 100-95.430 = 4.570%.
Fractional abundance of 235U = 95.430/100 = 0.95430; fractional abundance of 238U 4.570/100 = 0.04570.
Weighted average atomic mass = (0.95430 × 0439 amu) + (0.04570 × 238.0508 amu) = 235.18 amu.
Average atomic mass refers to the weighted atomic mass of an element.
Weighted average atomic mass is the sum of (fractional abundance × mass of the isotope) for all isotopes.
Looks like you have calculated a simple average. Average atomic mass refers to the weighted atomic mass of an element. The percent contribution from each isotope must be taken into consideration.
Weighted average atomic mass is the sum of (fractional abundance × mass of the isotope) for all isotopes.
Weighted average atomic mass is the sum of (fractional abundance × mass of the isotope) for all isotopes. Fractional abundance of 75X is 45.67/100= 0.4567; fractional abundance of 76X is 0.5302; fractional abundance of 77X = 0.0131.
Weighted average atomic mass = (0.4567 × 75.121 amu) + (0.5302 ×812amu) + (0.0131 × 77.112 amu) = 235.18 amu.
Weighted average atomic mass is the sum of (fractional abundance × mass of the isotope) for all isotopes.
Looks like you calculated a simple average and not a weighted average! The percent contributions from each isotope must be considered.
Most of the sample is made of 145X and 146 The average atomic mass cannot be close to 77 amu!
You will need the periodic table to determine this.
Answer based on the average atomic mass of Magnesium.
From the periodic table, we know that the average atomic mass of Magnesium is 24.31 amu. As the average mass is closer to Magnesium-24, it is likely that Magensium-24 contributes most to the average mass, hence, is the most abundant isotope.
You will need the periodic table to determine this.
Naturally occurring elements usually contain one isotope in a greater abundance than the rest.
Hint: fractional abundances add to 1. View similar
example 2.4.
Average atomic mass = Σ (fractional abundance × mass of isotope).
The average atomic mass from the periodic table = 10.811 amu; Let fractional abundance of 10B be x; the fractional abundance of 11B will be 1-x as fractional abundances must add up to 1.
811 amu = [(x)(10.013 amu) + (1-x)(11.009 amu)]
x = 0.1987; Percent abundance of 10B= 0.1987 × 100 = 19.87%
The average atomic mass of Boron can be obtained from the periodic table. Assume that the fractional abundance of
10B is x, the natural abundance of
11B is 1-x.
View similar
example 2.4.
Hint: fractional abundances add to 1. The average atomic mass of Boron can be obtained from the periodic table.
View similar
example 2.4.
Hint: fractional abundances add to 1. Substitute in the formula for average atomic mass.
View similar
example 2.4.
The percent abundances of 25Mg and 26Mg should add up to (100-78.99) %
The percent abundances of 25Mg and 26Mg should add up to (100-78.99) %
The percent abundances of 25Mg and 26Mg should add up to (100-78.99) %
The percent abundances of 25Mg and 26Mg should add up to (100-78.99) %
V2O5 contains metal (vanadium) and non-metal (oxygen). Metals want to lose electrons and form positive ions and non-metals want to gain electrons and form negative ions. The positive and negative ions attract by what are known as ionic bonds and the compound is said to be an ionic compound. Therefore, V2O5 is an ionic compound.
Since Nitrogen and Oxygen are both non-metals, N2O5 is a molecular compound.
A molecular compound is a substance with discrete molecules where in the atoms are bonded by covalent bonds (i.e. by sharing electrons). Usually, non-metals bond to each other by sharing electrons as there is not a significant difference in their abilities to lose/gain electrons. Therefore, compounds containing two non-metals will be molecular compounds.
Potassium is a metal and phosphorus is a non-metal. K3P is an ionic compound. It contains potassium that has lost electrons (K+) and phosphorus that has gained electrons (P3-) and the ions attract each other by what are known as ionic bonds.
Iron is a metal and chlorine is a non-metal. Metals want to lose electrons and form positive ions and non-metals want to gain electrons and form negative ions. The positive and negative ions attract by what are known as ionic bonds and the compound is said to be an ionic compound. Therefore, FeCl3 is an ionic compound.
Lithium is a metal. Metals want to lose electrons and form positive ions (Li+). Hydroxide is a negatively charged ion (OH-). The bonding between Li+ and OH- is ionic bonding. Hence, LiOH is an ionic compound.
Hydrogen and chlorine are both non-metals. Hydrogen and chlorine bond by sharing electrons, hence, HCl is a molecular compound.
Phosphorus and chlorine are both non-metals. Phosphorus and chlorine bond by sharing electrons, hence, PCl3 is a molecular compound.
C, H and O are all non-metals. They bond to each other by sharing electrons, hence, C2H5OH is a molecular compound.
Note: C2H5OH is commonly known as ethanol.
Aluminum is a metal and sulfur is a non-metal. The metal and non-metal from ions (Al3+, S2- ions) that bond together by ionic bonding. Therefore, Al2S3 is an ionic compound.
Selenium and bromine are both non-metals. They both bond by sharing electrons, hence, SeBr2 is a molecular compound.
Good job! AlBr3 is an ionic compound, so, naming it involves stating the cation name followed by the anion name (Br- is bromide). A roman numeral is not needed to specify the charge of aluminum, because aluminum which is in group 3A (or group 13) can only from one stable ion with a +3 charge.
Sorry! AlBr3 is an ionic compound. The prefixes mono, di, tri, etc. are used when naming molecular compounds!
A roman numeral is not needed to specify the charge of aluminum, because aluminum which is in group 3A (or group 13) can only from one stable ion with a +3 charge.
The anion in AlBr3 is Br-, which is a monoatomic The name of Br- ion is bromide, not bromite!
The anion in AlBr3 is Br-, which is a monoatomic The name of Br- ion is bromide, not bromate!
Type of compound: LiOH is an ionic compound.
Check formula: Lithium is in group#1, so lithium ion is Li+. The polyatomic anion is hydroxide (OH-). One Lithium ion (+1 total charge) and one hydroxide ion (-1 total charge) lead to a net charge of zero. So, the formula of the compound is correct.
Check name: An ionic compound should be named with cation name followed by anion name. The name lithium hydroxide is correct.
Type of compound: Rb2SO4 is an ionic compound.
Check formula: Rubidium is in group#1, so Rubidium ion is Rb+. The polyatomic anion is sulfate (SO42-). Two Rubidium ions (+2 total charge) and one sulfate ion (-2 total charge) lead to a net charge of zero. So, the formula of the compound is correct.
Check name: An ionic compound should be named with cation name followed by anion name. Hence, the name Rubidium sulfate is correct.
The name is not correct because roman numeral is needed while naming a transition metal ion.
Analyze:
Type of compound: FeCl3 is an ionic compound.
Check formula: Iron is a transition metal. The monoatomic ion is chloride (Cl-). Iron must have a charge of +3 to balance the charge from three chloride ions (Cl-) in the compound.
Check name: An ionic compound should be named with cation name followed by anion name. The name of the transition metal ion, Fe3+, is iron(III); the roman numeral in the parenthesis signifies the charge . Hence, the name of FeCl3 should be iron(III) chloride.
Type of compound: NaCH3COO is an ionic compound.
Check formula: sodium is in group#1, so lithium ion is Na+. The polyatomic anion is acetate (CH3COO- or C2H3O2-). One sodium ion (+1 total charge) and one acetate ion (-1 total charge) lead to a net charge of zero. So, the formula of the compound is correct.
Check name: An ionic compound should be named with cation name followed by anion name. Hence, the name sodium acetate is correct.
Note: sometimes, the formula is also written as CH3
Type of compound: NH4I is an ionic compound. (Note: Compounds that contain NH4+ ions are ionic compound because there are positive and negative ions, even though the cation is not a metal).
Check formula: The polyatomic cation is ammonium (NH4+). The anion is a monoatomic iodide ion; since iodine is in group 7A (or group 17), it’s formula is I-. One ammonium ion and one iodide ion lead to a net charge of zero. So, the formula of the compound is correct.
Check name: An ionic compound should be named with cation name followed by anion name. The name ammonium iodide is correct.
K2O is an ionic compound containing two potassium ions (K+) and one oxide (O2-) ion. It’s name, potassium oxide, is correct.
Ca3N2 is an ionic compound containing three calcium ions (Ca2+) and two nitride (N3-) ions. It’s name, calcium nitride, is correct.
VF5 is an ionic compound containing one Vanadium(V) ion (V5+) and five fluoride (F-) ions. It’s name, Vanadium(V) fluoride, is correct.
The name of the compound is Bromine monochloride.
BrCl is a molecular compound. It does not contain ions! Molecular compounds are named using prefixes such as mono, di, tri to specify the number atoms. The prefix, “mono” is dropped at the beginning of the compound name.
MgSe is an ionic compound containing one Magnesium ion (Mg2+) and one selenide ion (Se2-). Ionic compounds are named with the cation name followed by anion name. Hence, the name Magnesium selenide is correct.
Ca(NO3)2 is an ionic compound containing one Ca2+ and two NO3- The cation is calcium ion and the anion name is nitrate. Hence, calcium nitrate is the correct name.
The charge of cobalt ion is not correct in the formula.
Co2SO4 is an ionic compound containing a transition metal; charge of the metal ion must be specified in parenthesis when naming. There are two cobalt ions and one SO42- (sulfate) ion in the compound. To balance the total positive and negative charge, each cobalt ion has +1 charge. Hence, the compound name should be cobalt(I) sulfate.
K2CO3 is an ionic compound containing two K+ ions and one CO32- The cation is potassium ion and the anion name is carbonate. Hence, potassium carbonate is the correct name.
CuCl is an ionic compound containing a transition metal; charge of the metal ion must be specified in parenthesis when naming. There is one copper ion and one Cl- (chloride) ion in the compound. To balance the positive and negative charge. the copper ion has a +1 charge. Hence, the compound name Copper(I) chloride is correct.
(NH4)2S is an ionic compound containing two NH4+ and one sulfide ion S2-. The cation name is ammonium, and the anion name is sulfide. Hence, the name ammonium sulfide is correct.
Barium hydroxide is Ba(OH)2.
Nitrite is a polyatomic ion (NO2-). Strontium nitrite is Sr(NO2)2.
Ammonium phosphate is (NH4)3PO4.
Dichlorine heptoxide is Cl2O7.
Magnesium ion is Mg2+. Chlorate is ClO3-. Hence, the magnesium chlorate is Mg(ClO3)2. The formula is correct.
NO3- is nitrate. There are two nitrates in the compound, so, palladium has a charge of +2. The name, palladium(II) nitrate is correct.
The name Lithium sulfate is not correct.
The name of SO32- is sulfite since there is one oxygen less than sulfate. Hence. Li2SO3 should be Lithium sulfite.
CsI is an ionic compound. I- is iodide. The name of the compound is indeed Cesium Iodide.
CO32- is carbonate. Since there are two Nickel ions in the compounds, each Nickel has a charge of +1 to balance the total positive and negative charge in the compound. The name, nickel(I) carbonate is correct.
OH- is hydroxide ion. Hence KOH is potassium hydroxide.
Both cation and anion are not named correctly!
The compound is an ionic compound. Prefixes (such as mono) should not be used when naming ionic compounds.
The charge of chromium is not +1!
Great job! PO33- is phosphite ion (one oxygen less than phosphate). The charge on Chromium should be +3 to balance the positive and negative charge. Hence, the name of the compound is Chromium(III) phosphite.
The anion is not named correctly!
For metal cations other than Aluminum, group#1 and group#2 ions, the charge is specified using a roman numeral. So, a roman numeral is needed to specify the charge of the lead (Pb) ion.
BrO3- is bromate ion. Since there are two bromate ions in the compound, the charge on lead ion is +2 to balance the total positive and negative charge. Hence, Pb(BrO3)2 is correctly named lead(II) bromate.
There is a transition metal in the compound, so a roman numeral is needed in the cation name.
CO32- is carbonate. Since there are two gold ions in the compound, the charge on each gold ion is +1 so the total positive charge equals total negative charge. Hence, Au2CO3 is correctly named Gold(I) carbonate.
PO33- ion is a polyatomic ion; its name is phosphite since it has one oxygen less than phosphate. AlPO3 is Aluminum phosphite.
There is a transition metal in the compound, so a roman numeral is needed in the cation name.
The anion is oxide (O2-) ions. The total negative charge due to five oxide ions is -10. Since there are two vanadium ions, each has a +5 charge to balance the total positive and negative charge. V2O5 is correctly named Vanadium(V) oxide.
CS2 is a molecular compound. Prefixes are needed when naming the compound. Hence, carbon disulfide is the correct name.
Note that the prefix, “mono”, is dropped for carbon because it occurs at the very beginning of the compound name.
The anion in HCl is chloride (Cl-). So, the acid name is hydrochloric acid.
Note: If the anion name ends with “ide”, the corresponding acid’s name starts with “hydro” and ends with “ic acid” (ie. hydro _____ ic acid)
The anion in HClO4 is ClO4-. The name of anion is perchlorate (since it has one oxygen more than chlorate). So, the name of the corresponding acid, HClO4, is perchloric acid.
Note: if the anion is “per___ate” which has one oxygen more than “ate”, the corresponding acid is named “per_____ ic acid”.
The anion in the HClO3 is ClO3-. The name of anion is chlorate. So, the name of the corresponding acid, HClO3, is chloric acid.
Note: if the anion name ends with “__ate”, the corresponding acid name ends with “___ic acid”.
If the acid name ends with “ous acid”, the corresponding anion name ends with “ite”. So, the corresponding anion of chlorous acid is chlorite, which has one oxygen less than chlorate.
chlorite = ClO2-. Hence, chlorous acid = HClO2.
The anion in HClO is ClO-. The name of the anion is hypochlorite (since it has two oxygens less than ate). So, the name of the corresponding acid, HClO is hypochlorous acid.
Note: if the anion is “hypo___ite”, which has two oxygens less than “ate”, the corresponding acid is named “hypo____ous acid”.
The corresponding anion of sulfurous acid is sulfite.
Sulfite has one oxygen less than sulfate but has the same charge as sulfate. Therefore, sulfite is SO32-. Sulfurous acid is H2SO
The corresponding anion of phosphoric acid is phosphate. The formula of phosphate is PO43-. Hence, phosphoric acid is H3PO4, NOT H2PO4!
The corresponding anion of hydroiodic acid is iodide (I-). The formula of hydroiodic acid is HI, indeed!
The corresponding anion of carbonic acid is carbonate (CO32-). So, the formula of carbonic acid is H2CO3.
The corresponding anion of acetic acid is acetate (CH3COO- or C2H3O2-). So, the formula of acetic acid is CH3COOH or HC2H3O2).
Hint: Identify the name of the anion in HIO
4. Review nomenclature of binary and oxyacids
here.
Hint: Identify the name of the anion in HIO
4. Review nomenclature of binary and oxyacids
here.
The anion in HIO
4 is IO
4-. The name of IO
4- is per-iodate since it has one oxygen more than iodate (IO
3-). Hence the corresponding acid of periodate should be named periodic acid.
Review more examples of binary and oxyacid nomenclature
here.
Hint: Identify the name of the anion in HIO
4. Review nomenclature of binary and oxyacids
here.
Hint: Identify the name of the anion in HIO
4. Review nomenclature of binary and oxyacids
here.
Review how many oxygens are less in hypochlorite compared to chlorite.
Review how many oxygens are less in hypochlorite compared to chlorite.
Review how many oxygens are less in hypochlorite compared to chlorite.
Review how many oxygens are less in hypochlorite compared to chlorite.
Hypochlorite ion has two oxygens less than the chlorate ion. Chlorate ion is ClO3-; so, hypochlorite is ClO-. Therefore, sodium hypochlorite is NaClO.
PO43- is a phosphate ion. Hence, Na3PO4 is sodium phosphate.
The formula does not use the correct charge on hydrogen phosphate ion.
The formula NaHPO4 suggests that HPO4 has a -1 charge! Note that “hydrogen phosphate” ion is the ion that results when one H+ is added to phosphate (PO43-).
A “hydrogen phosphate” ion is the ion that results when one H+ is added to phosphate (H+ + PO43- = HPO42-; note that +1 charge from hydrogen and -3 charge from phosphate add to -2).
Since sodium (Na+) is the cation and hydrogen phosphate (HPO42-) is the anion, the formula for sodium hydrogen phosphate after the charges are criss-crossed is Na2HPO4.
NaH2PO4 is sodium dihydrogen phosphate as it contains sodium ion (Na+) and dihydrogen phosphate (H2PO4-) ions.
NaH
2PO
4 is sodium dihydrogen phosphate as it contains sodium ion (Na
+) and dihydrogen phosphate (H
2PO
4-) ions.
PO33- is a phosphite ion. Hence, Na3PO3 is sodium phosphite.