化学
化学反应、化学计量、分子结构与元素性质。
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which representation demonstrates a key limitation of lewis structures?…
The third structure (the one with double - bonded oxygen and single - bonded oxygens)
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part 2 (1 point) rank the bonds in the two molecules shown in order of …
1. C - H 2. C - O 3. O - H 4. C - F
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rank the bonds in the two molecules shown in order of increasing polari…
C - H, O - H, C - F
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rank the carbon - carbon bonds in the following hydrocarbons according …
1. $C_2H_4$ 2. $C_2H_6$
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how many valence electrons do each of the following species contain? 1s…
Part 1: 10 Part 2: 11 Part 3: 8 Part 4: 10
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if a 0.500 m aqueous solution freezes at -2.40 °c, what is the vant hof…
$i\approx2.58$
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question 45 water molecules have a slight bond between themselves and o…
B. hydrogen
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question 43 liquid fats called oils contain a. ring structures b. fat m…
D. long CH₂ chains linked by double covalent bonds and are often "kinked"
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a. organization of the periodic table 1. why do elements in the same gr…
Elements in the same group have the same number of valence electrons, which determines their similar physical and chemical properties.
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assuming 100% dissociation, calculate the freezing point (t_f) and boil…
$T_f=-23.1^{\circ}C$ $T_b = 106.38^{\circ}C$
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a chemist is using 334 milliliters of a solution of acid and water. if …
48.1
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question 38 this shows a pair of electrons in a covalent bond between t…
a. structural formula
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assuming equal concentrations and complete dissociation, arrange these …
Highest freezing point: $NH_4I$ Next: $Na_2CO_3$ Lowest freezing point: $CoBr_3$
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question 38 using the diagrams below: if cl interacted with na, cl woul…
d. gain an electron
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question 11 428 mols of mg are equal to 2.58×10²⁶ atoms of mg blank 1 4…
Question 11 Blank 1: 428 Question 12 Blank 1: 2.04 Question 12 Blank 2: 23
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k is the chemical symbol for which of the following substances? iron ba…
First question: D. Potassium Second question: A. Abnormal condition of stones
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question 13 the molar mass of c2h4(nh2)2 is 60 g/mol. blank 1 60
60 g/mol
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question 14 if a box of cacl₂ has a mass of 2.56 g. 0.0231 moles are in…
The values in the blanks are correct as they are consistent with the mole - mass and mole - atom relationships for $CaCl_2$.
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1. list three properties of the elements that are useful in sorting the…
Atomic number, Atomic mass, Electronegativity
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when your body burns 1.00 g of sucrose, blank 1 grams of oxygen is burn…
$1.12$
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question 19 using the equation 2li + 2h₂o → 2lioh + h₂ when 2.5 g of li…
93.5%
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question #3 not yet answered points out of 3.00 flag question are the f…
A. both
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decide whether each pair of elements in the table below will form an io…
| element #1 | element #2 | Forms ionic compound? | empirical formula of ionic compound | | ---- | ---- | ---- | ---- | | barium | bromine | yes | $BaBr_{2}$ | | sulfur | fluorine…
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having problems staying logged in or are you experiencing issues? pleas…
Selenium (Se)
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note: to answer some of the questions, it may help to reference a perio…
B. alpha radiation
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fill in the name and empirical formula of each ionic compound that coul…
| Cation | Anion | Empirical formula | Name of compound | | ---- | ---- | ---- | ---- | | $Ca^{2+}$ | $BrO_{3}^{-}$ | $Ca(BrO_{3})_{2}$ | Calcium bromate | | $NH_{4}^{+}$ | $CrO_{…
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3. analyze: an isotope is an alternative form of an element. each isoto…
A. Carbon - 12, Carbon - 13 B. Nitrogen - 14, Nitrogen - 15 C. Oxygen - 13, Oxygen - 15
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select all steps below that help you handle chemicals safely. using dro…
using droppers to transfer small amounts of chemicals checking the test tubes for chips prior to using them washing your hands after you finish the lab
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listed in the item bank are key terms and expressions, each of which is…
Metals: Good conductor, High luster, Left side of PT Metalloids: An element with intermediate properties Nonmetals: Right side of PT, Noble Gas
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potential energy was transferred into each of the following objects to …
stone - potential energy of slingshot arrow - potential energy of bowstring baseball - stored energy in human arm cannonball - chemical potential energy of gunpowder
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use the graph on the right to answer the following questions. a. estima…
c. 35000 feet; There is no altitude at which the pressure is exactly zero because there will always be some air molecules present in the atmosphere, resulting in a non - zero (alb…
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question 5 (1 point) wood chips are what type of food safety hazard? ch…
B. Physical
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the factor - label method can be used to solve virtually any problem in…
1. 0.035 L 2. 0.95 kg 3. 27.5 cm 4. 1 kL 5. 1 L 6. 4.5 g 7. 250 mm 8. 0.5 dag 9. 7.5 cm 10. 15000 mg
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question 4 (1 point) false ownership is a violation of the rules and gu…
TRUE ### Question 5
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chem 203 - tutorial 1: stoichiometry and gas properties part 1 - group …
No specific final answer due to incomplete problem statement. General steps for solving are provided above.
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ch₂o how many atoms of carbon were in the reactants of this equation gi…
1
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solve the following problems. write the answers in significant figures.…
1. 10800 2. 0.0035 3. 12.1 4. 90 5. 11388 6. $1.806\times 10^{24}$ 7. 4.15 8. 112 9. 4.46 10. $1.34\times10^{24}$ 11. 186 12. 7.5
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which choice provides the best summary of the passage? the maillard rea…
The Maillard reaction is a chemical reaction that occurs between acids and sugars, causing foods to brown and gain a rich flavor. This process enhances the smell and taste of cert…
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alculate the density of the following objects. object\tmass (g)\tvolume…
Oxygen density: 0.0014 g/mL Water density: 1 g/mL
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drag and drop each description to classify is as a characteristic of me…
Metals: Have the highest melting and boiling points, Are very ductile Metalloids: Intermittent properties Nonmetals: Have the lowest melting and boiling points, Includes most gases
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how do soils form? o plants cement mineral particles together to form s…
Weathering breaks rocks into minerals, and plants die and decay.
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how does the inorganic portion of soil form? soils get formed by meltin…
Rocks get weathered by chemical and physical means to form soils.
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part 1: use the notation below to answer the following questions. 12c 1…
| Hyphen Notation | Nuclear Notation | Atomic # | Mass # | # of $p^{+}$ | # of $n^{0}$ | # of $e^{-}$ | |---|---|---|---|---|---|---| | Uranium - 235 | $^{235}U$ | 92 | 235 | 92 |…
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which element has the smallest ionization energy, na, f, i, cs? cs beca…
Cs because, as an alkali metal with a large size, there is a weak electrostatic attraction between the protons and the valence electrons.
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listed in the item bank are key terms and expressions, each of which is…
Metals: Ductile and malleable, Sodium, Magnesium, Iron Metalloids: Semiconductor, Silicon, Germanium, Arsenic Nonmetals: Oxygen, Nitrogen, Neon, Poor conductors
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what is the overall trend for the electron affinity of atoms across the…
Electron affinity decreases down the groups and increases from left to right across the periods.
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moving left to right across the periodic table, electronegativity _____…
C. increases; decreases
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why do we use metals in wires? (select all that apply.) metals are reac…
Metals conduct electricity., Metals are ductile.
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which family has a full valence shell, making them the least reactive g…
noble gases
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how can the chemical formula for methane (ch4) be explained if carbon h…
The carbon atom promotes one electron from the s orbital into the p orbital, which creates four half - filled orbitals available to accept one electron from four different hydroge…
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2: complete the chart below. | hyphen notation | nuclear notation | ato…
| Hyphen Notation | Nuclear Notation | Atomic # | Mass # | # of $p^{+}$ | # of $n^{0}$ | # of $e^{-}$ | | ---- | ---- | ---- | ---- | ---- | ---- | ---- | | Uranium - 235 | $^{235…
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place these atomic models in order from oldest to most recent. a b c d …
C, A, D, B
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note: to answer some of the questions, it may help to reference a perio…
The metals at the bottom of the periodic table are more reactive than metals at the top of the periodic table. The metals farthest to the left of the periodic table are the most r…
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note: to answer some of the questions, it may help to reference a perio…
A. The metals at the bottom of the periodic table are more reactive than metals at the top of the periodic table. B. The metals farthest to the left of the periodic table are the …
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what is a main difference between the modern atomic model and bohrs pla…
Electrons do not orbit the nucleus on fixed paths.
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which statement correctly defines an elements reactivity? a property de…
a property describing how readily atoms engage in a chemical reaction when they interact
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how many valence electrons does sulfur have? sixteen valence electrons …
six valence electrons
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what is the electron configuration for tin (sn), with an atomic number …
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p²
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6. looking at your answers to questions 1 and 2 from model 1, tell what…
a. Hydrogen atoms b. Oxygen atoms 7. Covalent bonds 8. Hydrogen bonds 9. a. Partial negative charge b. Partial positive charge 10. Arranged with hydrogen of one molecule attracted…
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if an element has the atomic number 20, what sublevels are present? it …
The first energy level has an s; the second and third energy levels have an s and a p; the fourth energy level has an s.
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note: to answer some of the questions, it may help to reference a perio…
C
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properties of water pogil what makes water so special? why? when you he…
1. 2 2. 1 3. Covalent bond 4. The electron density around the oxygen atom is higher than that around the hydrogen atoms. 5. On the oxygen atom.
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question 4 (mandatory) (10 points) the public health department nurses …
C. Two or more people having experienced a similar illness after exposure to water
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note: to answer some of the questions, it may help to reference a perio…
1
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when a potassium (k) ion is formed, what is its charge and why? a potas…
C. A potassium ion will form a 1+ charge because it will lose one electron to achieve a full valence level.
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which statement correctly identifies the nuclide that is most likely to…
Uranium-238 ($^{238}$U) is likely an unstable nuclide because it has a neutron - to - proton ratio that is 1.6:1 and for light elements the ideal neutron - to - proton ratio is 1:…
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note: to answer some of the questions, it may help to reference a perio…
87.62 amu
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consider the scenario. an unknown element has been discovered. the atom…
The atomic number is 212, and the atomic mass is 529. So the correct option is: The atomic number is 212, and the atomic mass is 529.
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note: to answer some of the questions, it may help to reference a perio…
Lead (Pb)
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use the periodic table and your knowledge of atomic structure to match …
Sodium (Na) - $1s^{2}2s^{2}2p^{6}3s^{1}$ Phosphorus (P) - $1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}$ Chlorine (Cl) - $1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}$ Arsenic (As) - $1s^{2}2s^{2}2p^{6}3s^{2…
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why is atomic mass measured in atomic mass units (amu)? electrons and n…
Protons and neutrons make up nearly all the mass of an atom, and each is worth 1 amu. Each atom of an element has a mass measured in amu; thus, its weighted average, or atomic mas…
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note: to answer some of the questions, it may help to reference a perio…
The percent abundance for each isotope of an element (in decimal form) is multiplied by its mass. Then, the calculated values of all isotopes for that element are summed. Atomic m…
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note: to answer some of the questions, it may help to reference a perio…
The first choice (where the arrows between the proton and electron point towards each other) is correct.
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note: to answer some of the questions, it may help to reference a perio…
The electrostatic force between protons and electrons is an attractive force.
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what new characteristic did john dalton add to the model of the atom? a…
A. An atom is a round, solid mass. D. An atom can join with other kinds of atoms.
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note: to answer some of the questions, it may help to reference a perio…
The plum - pudding model did not identify a central nucleus as the source of a positive charge.
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use the periodic table and your knowledge of atomic structure to match …
Chromium (Cr): $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{5}$ Arsenic (As): $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{3}$ Chlorine (Cl): $1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}$ Phosp…
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which statement belongs to daltons atomic theory? atoms have a massive,…
Atoms cannot be created or destroyed.
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which electron configuration is not a configuration of a stable main - …
B. $1s^{2}2s^{2}$
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note: gloves are never worn when working on machines with rotating part…
All statements are correct.
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question 10 (1 point) (02.03 mc) the following orbital notation is for …
b. N ### Question 11
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question 9 (1 point) (02.03 mc) the diagram shows four different locati…
B. 2 and 3
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which scientist developed the first model of the atom that proposed the…
D. Thomson
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question 7 (1 point) (02 03 mc) magnesium (mg) has an atomic number of …
Question 7: C. $1s^{2}2s^{2}2p^{6}3s^{2}$ Question 8: C. 1 and 4
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when analyzing electron configurations, the stability of a particular m…
For the first question: D. s and p For the second question (assuming the options continue from the first part and we are looking for an unstable main - group configuration): Infor…
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question 4 (1 point) (02.03 lc) what type of orbital is spherical in sh…
Question 4: A. s orbital Question 5: B. p orbital Question 6: C. \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\)
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question 1 (1 point) (02.03 lc) what is the total number of electrons t…
Question 1: b. 6 electrons Question 2: c. 10 electrons Question 3: d. 14 electrons
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cold or hot objects. sharp edges. note:gloves are never worn when worki…
B. Chemicals C. Cold and hot objects D. Electricity E. Sharp edges
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use the list to answer the question. • potassium, group ia • calcium, g…
potassium and iodine
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fluorine has 7 valence electrons. which charge is its ion likely to hav…
1-
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question 19 (1 point) (02.02 mc) the image shows the representation of …
B. The number of neutrons in an atom of the element is 10.
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ions quick check when moving across a period from left to right in the …
Valence electrons increase by one
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question 18 (1 point) (02.02 mc) the image shows the representation of …
c
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many accidents can be prevented by wearing protective clothing. it prot…
Flame retardant clothing is suitable for welding. High visibility clothing can be used when working at the road side. Impervious clothing is suitable when working with chemicals, …
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ions quick check based on the naming rules for ions, which of the follo…
B. chloride
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question 17 (1 point) (02.02 mc) the image shows the representation of …
d. The mass number of the most common isotope of the element is 24.
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question 14 (1 point) (02.02 mc) zinc has the chemical symbol zn and th…
Question 14: d. 30 protons, 39 neutrons, 30 electrons Question 15: b. 6 Question 16: d. 11
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show all calculation setups. adjust for significant figures and give un…
$63.65$ amu (adjusted to four significant figures)
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part b which statement is true regarding main - group families of the p…
C. Lithium is an alkali metal that loses 1 electron to become a cation to become stable.
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question 11 (1 point) (02.02 lc) which of the following best describes …
Question 11: B. Brittle, dull, and low density Question 12: B. Metal Question 13: B. 28 protons, 50 neutrons, 28 electrons