化学
化学反应、化学计量、分子结构与元素性质。
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which of the following is an example of a physical change? choose one o…
B. honey dissolving in tea
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which one of the following substances will have both dispersion forces …
d) \(HCl\)
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choose one option a liquid evaporating into gas b a solid formed from a…
C. a chunky solid formed from two liquids combining
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true or false: a physical change may produce a new substance. choose on…
B. False
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question 8 (1 point) ✓ saved given the following reaction mechanism, wh…
\(2A\to 2E + F\) (First option)
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what is the predominant intermolecular force in cbr₄? a) hydrogen bondi…
d) london dispersion forces
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knowledge check question 1 which statement is true? most elements are n…
Other than noble gases, the atoms in most elements are bonded to other atoms.
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3) the titration of 25.00 ml of a vinegar sample with 0.500 m naoh requ…
a. The mass of acetic acid is \(1.34\space g\). b. The percent of acetic acid is \(5.36\%\)
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question 23 (1 point) listen which of the following shows the correct d…
b) Dipole B
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consider the oil and vinegar lab with hexane and h2o forming 2 layers i…
C. \(CH_{3}OH\)
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use the densities of the substances below to determine how they will se…
Rubbing Alcohol, Baby Oil, Water, Milk, Honey.
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which category of compounds had a larger boiling point during the imf l…
d) Alcohols; Hydrogen bonding
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question 10 (1 point) why does the rate of reaction increase with incre…
A greater proportion of all the molecules possess kinetic energy that is equal to or greater than the activation energy.
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question 9 (1 point) why does an increase in concentration increase the…
The number of collisions increases.
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question 8 (1 point) given the following reaction mechanism, what is th…
\(2A + C\to2E + F\) (the fifth option)
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question 7 (1 point) potential energy diagram use the potential energy …
the heat of reaction
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balancing equations workshop 10. ____ kno₃ + ____ h₂co₃ → ____ k₂co₃ + …
\(2KNO_3 + 1H_2CO_3 ightarrow1K_2CO_3+2HNO_3\)
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which of the following molecules is not polar? a) of₂ b) cf₄ c) ch₃cl d…
B. \(CF_4\)
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question 6 (1 point) which statement about the factors that affect reac…
A reaction occurs every time particles of the reactants collide.
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which of these species can exhibit hydrogen bonding among themselves? a…
d) \(N_2H_4\)
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question 5 (1 point) which quantity does not increase when the temperat…
activation energy
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12. ____ (nh₄)₃po₄ + ____ pb(no₃)₄ → ____ pb₃(po₄)₄ + ____ nh₄no₃
\(4(NH_{4})_{3}PO_{4}+3Pb(NO_{3})_{4}\to Pb_{3}(PO_{4})_{4}+12NH_{4}NO_{3}\)
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question 4 (1 point) potential energy diagram use the potential energy …
the activation energy of the forward reaction
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practice: balance and rewrite the following chemical equations 5. $agno…
5. \(2AgNO_3 + H_2S = Ag_2S + 2HNO_3\) 6. \(3Zn(OH)_2 + 2H_3PO_4 = Zn_3(PO_4)_2 + 6H_2O\) 7. \(Cu(s)+2AgNO_3(aq)=Cu(NO_3)_2(aq)+2Ag(s)\) 8. \(4Al(s)+3O_2(g)=2Al_2O_3(s)\) 9. \(FeC…
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question 3 (1 point) consider the following reaction mechanism. changin…
A.
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question 2 (1 point) potential energy diagram use the potential energy …
the heat of reaction
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question 1 (1 point) which step of a reaction is the rate - determining…
the slowest step
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question 18 (1 point) listen when comparing boiling points of alkanes v…
The alkane has the greater change in boiling point (steeper slope) with increasing molar mass.
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which option below is correct representation for a hydrogen bond? a) di…
C. Diagram C
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question 12 (1 point) use the following information to answer the next …
In the above reaction, one mole of a compound is formed from its elements.
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2) a student standardized a naoh solution using h₂c₄h₄o₄. three h₂c₄h₄o…
Determination 1: \(0.00229\space mol\) Determination 2: \(0.002535\space mol\) Determination 3: \(0.002383\space mol\)
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based on the provided electronegativity values, which bond could be des…
\(H - P\)
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question 11 (1 point) m grams of sucrose give enthalpy change of δh kj/…
The enthalpy change doubles.
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question 15 (1 point) consider the properties lab with the three tests …
Covalent Acid: Citric Acid (\(C_6H_8O_7\))
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question 10 (1 point) if a chemical reaction at stp is carried out in f…
be the same as in the second method
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consider the following two reactions: (i) 2c₂h₄o(ℓ) + 2h₂o → 2c₂h₆o + o…
C. Endothermic, Exothermic
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question 7 (1 point) ✓ saved use the following information to answer th…
-2002 kJ
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choose the correct example. mg(c₂h₃o₂)₂, the number of h atoms is 3 mg(…
\(Mg(C_{2}H_{3}O_{2})_{2}\), the number of \(H\) atoms is \(6\)
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in a chemical formula, how do you calculate the number of atoms of an e…
By multiplying the parentheses subscript by the subscript of each element within the parentheses.
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what is a chemical formula? a chemical formula is a symbolic representa…
NaCl, CO₂, C₆H₁₂O₆
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question 7 (1 point) use the following information to answer the next q…
-2002 kJ
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what is a chemical formula? a chemical formula is a symbolic representa…
A. A chemical formula is a symbolic representation of the types and number of atoms of each element present in a compound.
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what is a chemical formula? a chemical formula is a symbolic representa…
- First question: A chemical formula is a symbolic representation of the types and number of atoms of each element present in a compound. - Second question: \(NaCl\), \(CO_2\), \(…
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how many oxygen atoms are in the formula of magnesium nitrate, mg(no₃)₂…
6
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how might the world be different if elements did not combine to form co…
The world would be very different - life could not exist.
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the bodys automatic response to any physical or mental demand placed on…
- Question 1: Stress - Question 2: Adrenaline - Question 3: Eustress
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question 12 (1 point) saved listen what is the name of n₂o₅? dinitrogen…
dinitrogen pentoxide
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part a which of the following substances can have variable composition?…
air
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question 11 (1 point) saved listen what is the name of the polyatomic i…
e) hydroxide
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question 5 (1 point) how much heat is gained when the temperature of 28…
B. \(30168\space J\)
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balancing chemical equations worksheet 1. 2 h2 + 2 o2 -> 2 h2o 2. 2 mg …
2. \(2Mg + O_2 ightarrow 2MgO\) 3. \(2Li+F_2 ightarrow 2LiF\) 4. \(4K + O_2 ightarrow 2K_2O\) 5. \(2H_2O_2 ightarrow 2H_2O+O_2\) 6. \(2Al + 3Cl_2 ightarrow 2AlCl_3\) 7. \(2Ag_2O i…
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4. hcl is a corrosive colourless gas that dissolves readily in water. a…
The molar enthalpy change for the reaction is \(-74.2\space kJ/mol\)
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question 3 (1 point) the enthalpy change for reaction $n_2 + 3h_2(g) \\…
C. \(-46.1\space kJ/mol\)
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question 10 (1 point) ✓ saved listen what is the formula for the ionic …
E. BaS
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how many oxygen atoms are in the formula fe₂(cr₂o₇)₃? view available hi…
21
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part a write a chemical formula for a compound that contains two oxygen…
\(\text{ClO}_2\)
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question 2 (1 point) use the following information to answer the next q…
$H_p < H_r$
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what is the name of the polyatomic ion, so₃²⁻? a) sulfurous b) sulfate …
d) sulfite
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reference tablesduring the quiz. however, as stated in the course outli…
$H_2(g)+\frac{1}{2}O_2(g)\to H_2O(l)\ \Delta H =$ negative (the second option)
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what is the systemic name for tiso₄? a) titanium sulfide b) titanium(iv…
d) titanium(II) sulfate
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choose the correct example. mg(c₂h₃o₂)₂, the number of h atoms is 6 mg(…
\(Mg(C_2H_3O_2)_2\), the number of H atoms is \(6\)
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question 6 (1 point) listen which of the following statements is true r…
Ionic compounds are composed of cations and anions in a fixed ratio.
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part a in a chemical formula, how do you calculate the number of atoms …
By multiplying the parentheses subscript by the subscript of each element within the parentheses.
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question 5 (1 point) bonds between two non - metals is called... a) a m…
B. a covalent bond.
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what is a chemical formula? a chemical formula is a symbolic representa…
- First question: A chemical formula is a symbolic representation of the types and number of atoms of each element present in a compound. - Second question: \(C_6H_{12}O_6\), \(Na…
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how many oxygen atoms are in the formula of magnesium nitrate, mg(no₃)₂…
6
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if you were asked to measure out approximately 5 ml of liquid, which la…
1. 10 mL Graduated Cylinder 2. 3.0106 g
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how might the world be different if elements did not combine to form co…
The world would be very different - life could not exist.
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which of the following substances can have variable composition? view a…
air
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which elements combine to form ordinary table salt? view available hint…
sodium and chlorine
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consider the 10 ml graduated cylinder. when recording a volume from thi…
hundredth decimal
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3. examine the reaction mechanism found below: a + b₂ → ab₂ (slow) ab₂ …
a. Reaction intermediates: \(AB_{2}\), \(AB_{2}C\), \(B_{2}C_{2}\) b. Catalyst: \(A\) c. Overall equation: \(2C + B_{2}\to D + E\) d. Rate law: \(rate = k[A][B_{2}]\)
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1. which element reacts with oxygen to form ionic bonds? a) calcium b) …
1. A. calcium 2. B. Group 2 3. A. broken as energy is absorbed 4. B. A bond is formed as energy is released 5. A. Ne 6. A. HI
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the formula for aluminum nitrate is al(no₃)₃. how many total atoms are …
Aluminum: \( 4 \) Nitrogen: \( 12 \) Oxygen: \( 36 \) Total atoms: \( 52 \)
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multiple choice 1 point what is the total number of atoms in nh3? 4 3 2…
4
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what is the total number of atoms in nacl? 1 4 3 2 clear my selection p…
\(2\)
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wilma was assigned to determine the density of nickel. she reported the…
\(13.2\%\)
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what is the first job of the small intestine? ingest food eliminate was…
digest macromolecules
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question 1 (mandatory) (3 points) listen how does regular exercise help…
During exercise, the brain releases endorphins, the chemicals that help improve our mood.
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experimental = 62.5g actual = 65.2g. what is the percent error? 12.4% 4…
\(4.1\%\)
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calculate the total number of each atom in 5k₂cr₂o₇. k type your answer…
K: \(10\), Cr: \(10\), O: \(35\)
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5 fill in the blank 3 points a compound has the formula 3al(oh)₃. how m…
Aluminum: \(3\) Oxygen: \(9\) Hydrogen: \(9\)
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an experiment to determine the volume of a \mole\ of gas was assigned t…
16.5%
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how many oxygen atoms are in co₂? 1 3 2 4 clear my selection
2
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how many hydrogen atoms are in one molecule of c₆h₁₂o₆? 6 18 24 12 clea…
12 (the fourth option)
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how many atoms are in one molecule of h₂o? 4 1 3 2
3
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1. using the following reactions, calculate the heat of formation, \\( …
The heat of formation of $\text{CS}_2$, $\Delta H_f = 128.02\ \text{kJ}$
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counting atoms assessment 1 fill in the blank 1 point if the chemical f…
\(16\)
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counting atoms assessment 1 fill in the blank 1 point if the chemical f…
\(16\)
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question 10 (1 point) which statement about the factors that affect rea…
A reaction occurs every time particles of the reactants collide.
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question 9 (1 point) potential energy diagram use the potential energy …
the heat of reaction
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question 8 (1 point) potential energy diagram use the potential energy …
the heat of reaction
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question 7 (1 point) why does an increase in concentration increase the…
The number of collisions increases.
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question 6 (1 point) which step of a reaction is the rate - determining…
the slowest step
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carbon atoms generally have ______ neutrons. a six b three c one d five
A. Six
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atoms of carbon - 14 have ____ neutrons. a 14 b 12 c 8 d 6
C. 8
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the number of neutrons and protons in calcium - 40 are ______ and _____…
D. \(20,20\)
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all atoms of the element sodium have 11 protons. how many neutrons are …
C. 12
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question 5 (1 point) which quantity does not increase when the temperat…
activation energy
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choose the correct nature of the energy profile diagram of an exothermi…
Downhill