化学
化学反应、化学计量、分子结构与元素性质。
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1. the law of ____ states that a single compound is always composed of …
1. c. definite proportions 2. b. iron 3. c. a physical combination of any two or more substances, as long as each substance retains its own chemical properties 4. b. element 5. c.…
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the octet rule is a valence shell that is only half full. true false
False
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1) for a 4 in 15 dilution, what is the ratio of urine to water? what is…
The ratio of urine to water is $\frac{4}{11}$. The ratio of water to total volume is $\frac{11}{15}$.
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the law of of mass states that mass is neither nor destroyed. in other …
The blanks should be filled as follows: Conservation; created; balance.
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match the following reaction to the correct description 4al + 3o₂ → 2al…
\(4Al + 3O_2 ightarrow2Al_2O_3\): synthesis \(2H_2O ightarrow2H_2 + O_2\): decomposition \(Ba+MgSO_4 ightarrow BaSO_4 + Mg\): single replacement \(HCl + KOH ightarrow KCl+H_2O\): …
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match the example with the type of change digesting food cutting up foo…
Digesting food - Chemical change Cutting up food - Physical change
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what gives each state its characteristic properties? ○ the mass of a su…
the particles that make up a substance
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which is a substance that is made of only one type of atom? absolute ze…
element
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a chemical formula uses chemical symbols to identify the elements in th…
subscripts
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the rainwater that flows down a trees trunk, called stemflow, plays a v…
D. Future research is guided by an awareness of what is already well understood about stemflow and what has yet to be adequately addressed.
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subjects and predicates a. writing subjects and predicates write senten…
**Part A** 1. A long column of numbers was difficult to calculate. 2. Her brother and sister played in the park. 3. The elements on the periodic table have unique properties. 4. T…
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this painting is by pablo picasso, entitled the blind mans meal. what t…
c. He used an analogous color scheme, which occurs when the hues used are next to one another on the color wheel
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which elements form lipids? periodic table of the elements
Carbon, hydrogen, oxygen
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chemical & physical changes online wk sheet which of the following is a…
has varying properties
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identify: tetrasaccharide disaccharide monosaccharide polysaccharide
Tetrasaccharide
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version id: a 9. which of the following is true about compounds? a. the…
9. c. They are chemically combined from 2 or more elements in definite proportions. 10. b. air 11. b. heterogeneous 12. d. The total mass of the reactants equals the total mass of…
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question 15 which of the following lewis structures represents a nonpol…
Question 15: D. :O=Xe=O: Question 16: D. sp²-sp²
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21. an example of a heterogenous mixture is a. brass b. tap water c. sw…
21. d. lemonade with pulp 22. b. The % mass composition of a compound will be increase when you have more total mass of the compound. 23. c. homogenous mixture, e. solution 24. b.…
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what two monosaccharides make up the disaccharide sucrose? glucose, fru…
Glucose, Fructose
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the diagrams in the box represent the lewis dot structures for differen…
C.
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1000.0 ml of water is added to 300.0 ml of 5.00 m h₂so₄. determine the …
The new molarity in the first part is $1.15\ mol/L$. For the multiple - choice question: 600 mL (corresponding to the correct option which is not labeled but should be the one wit…
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what is the correct electron dot formula for carbon dioxide? ○ :o::c::o…
The correct electron - dot formula for carbon dioxide is $\ce{O::C::O}$. So the answer is the first option $\ce{:O::C::O:}$ (assuming the first option is the one with two double b…
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the molar masses and boiling points at standard pressure for four compo…
A. HF
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what molecule in the graph above has the weakest intermolecular forces?…
CH₄
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1000.0 ml of water is added to 300.0 ml of 5.00 m h₃po₄. determine the …
$1.15M$
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what trend in intermolecular forces explains the increase in boiling po…
The amount of London dispersion forces increases as molecular weight increases.
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hester, treyvon dtal - ch - term 1 - unit 4b assessment - 25 - 26 which…
Trigonal Pyramidal, Bent
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hester, treyvon dtal - ch - term 1 - unit 4b assessment - 25 - 26 which…
The second - structure (H₂C = O) results in a polar compound.
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hester, treyvon dtal - ch - term 1 - unit 4b assessment - 25 - 26 what …
$N_2S_4$
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dtal - ch - term 1 - unit 4b assessment - 25 - 26 compared to h₂s, the …
B. stronger hydrogen bonding in water
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multiple - choice question solutions can best be described as heterogen…
B. homogenous mixtures
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which statement describes carbons unique bonding ability? carbon can bo…
Carbon can easily form 4 covalent bonds with other atoms.
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which molecules are considered organic? those containing phosphorus all…
those containing carbon
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dtal - ch - term 1 - unit 4b assessment - 25 - 26 use the terms below t…
intermolecular force
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according to vsepr, which compound could have the structural shape that…
C. $CH_3Cl$
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which statement best explains why carbon is present in so many kinds of…
It can form four covalent bonds.
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which of the following elements, when bonded, would result in a polar c…
C - O
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what is the most important role of hydrogen bonding between water molec…
It enables water molecules to bond to each other.
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part 2 consider the data below: isotopes with a known natural abundance…
1. They have the same number of protons (same element) and different number of neutrons. 2. Average atomic mass calculation: $A_{avg}=(24\times0.7899)+(25\times0.1000)+(26\times0.…
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part 1 isotopes of the element titanium most of the isotope data on thi…
1. All isotopes have 22 protons. Number of neutrons vary: 24 for mass - number 46, 25 for 47, 26 for 48, 27 for 49, 28 for 50. Similar in chemical properties, different in physica…
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hester, treyvon dtal - ch - term 1 - unit 4b assessment - 25 - 26 choos…
carbon tetrachloride
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foam cups are used to insulate the calorimeter temperature from the out…
a. TRUE
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when the system is open to the outside air, a constant pressure is main…
b. TRUE
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when solid ammonium chloride is dissolved in water in a calorimeter, th…
a. The reaction is endothermic because heat transfers from the water to the solid.
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30.0 ml of 2.0 m nh₃(aq) at 21.0°c is mixed with 30.0 ml of 2.0 m hcl(a…
B. -3.15 kJ
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a reaction takes place in aqueous solution in a calorimeter. the water …
A. the surroundings
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which statement is true about water molecules? the hydrogen atoms do no…
B. The oxygen atom has a slight negative charge.
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ingredient of smog and is harmful for people to breathe. bad ozone is c…
It informs readers about the negative effects of air pollution on life.
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which statement is true when a crystal is formed from many metal atoms?…
There are many molecular orbitals.
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which statement best describes the basis of the band theory of metallic…
Atomic orbitals overlap to form molecular orbitals in which the valence electrons of the atoms travel.
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which property is true for metals? localized electrons high electronega…
low ionization energies
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which is the best metal to use in an alloy to increase its electrical c…
B. Cu
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which reason best explains why metals are ductile instead of brittle? ○…
because they have flexible bonds
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which characteristics of metal atoms help explain why valence electrons…
Metal atoms are large and have low electronegativities.
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in a piece of metal, what holds the atoms together? o the positive char…
the positive charges of the nuclei and the negative charges of delocalized electrons
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what is another name for the molecular orbital theory of bonding in met…
band theory（能带理论） 对应的选项是：A. band theory
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which is most likely the result of millions of metal atoms crowding tog…
the formation of bands in a crystal
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boron has two isotopes: boron - 10 and boron - 11. which is more abunda…
1. Boron - 11 is more abundant. 2. The average atomic mass of copper is 63.6 amu. 3. The average atomic mass of bromine is 80.8 amu.
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ch 5 pt 2 hw element atomic # protons electrons k 19 19 5 16 23 boron h…
| Element | Atomic # | Protons | Electrons | | ---- | ---- | ---- | ---- | | K | 19 | 19 | 19 | | B | 5 | 5 | 5 | | S | 16 | 16 | 16 | | V | 23 | 23 | 23 | Boron - 11 is more abun…
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8. it is required to consume 25~30 ml of a 0.1 mol·l⁻¹ naoh solution du…
The mass of $KHC_{8}H_{4}O_{4}$ should be $0.51 - 0.61\ g$, and the relative errors of weighing are about $0.03 - 0.04\%$. The mass of $H_{2}C_{2}O_{4}\cdot2H_{2}O$ should be $0.1…
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name: date: what is the charge of the nucleus of every atom? why is an …
1. Positive charge. 2. The number of protons equals the number of electrons. 3. The number of protons in the nucleus. 4. The number of neutrons. 5. The relative abundance and mass…
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how many molecules of so₂ are present in 79g so₂? {____ x 10²³ molecule…
$7.43$
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6. weigh 0.5208 g of the primary standard khc₈h₄o₄ to standardize the n…
$0.1000\ mol\cdot L^{-1}$
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5. accurately weigh 1.4710 g of the primary standard k₂cr₂o₇, dissolve …
$c(K_2Cr_2O_7)=0.02\ mol/L$, $c(1/6K_2Cr_2O_7)=0.12\ mol/L$
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when is a roman numeral most likely needed in the name of an ionic comp…
when the cation is a transition metal
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3. calculate the concentration of glacial acetic acid (containing 99.6%…
$2.86\ mL$
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what is the chemical formula of a compound that is composed of the ions…
B. CaBr2
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what name should be used for the ionic compound cu(no₃)₂? copper nitrat…
copper(II) nitrate
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what is the name of the ionic compound albr3? bromine aluminide bromine…
aluminum bromide 对应的选项
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what name should be used for the ionic compound lii? ○ lithium iodide ○…
lithium iodide
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how many ions that have a +1 charge will bond with an ion that has a -2…
B. two
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what is the ratio of sodium ions to bromide ions in neutral sodium brom…
A. 1:1
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which statement describes how the binary ionic compound cacl2 is named?…
The nonmetal is named second, and the ending is replaced with -ide.
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draw the lewis structure of brf₃ and then determine the ideal bonding a…
D. \(90^{\circ}\) and \(120^{\circ}\)
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what name should be used for the ionic compound co₂(so₄)₃? ○ cobalt(iii…
cobalt(III) sulfate
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what is the chemical formula for ammonium sulfate? o nh₄(so₄) o nh₄(so4…
D. $(NH_4)_2SO_4$
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what was the ratio in the formula for iron (ii) oxide? what was the rat…
The ratio in the formula for iron (II) oxide is 1:1. The ratio in the formula for iron (III) oxide is 2:3.
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read the article and answer the following questions. ionic bonding why …
Na has +1 charge and O has -2 charge.
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1: calculate the titer of a 0.01135 mol·l⁻¹ hcl solution against naoh. …
$4.541\times10^{-4}\ g/mL$
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draw the lewis structure of nitrous acid (hno₂) and then choose the app…
A. bent (109.5°)/ bent (120°)
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model b which statement best explains how the models differ? model a sh…
Model A shows the sharing of electrons, and model B shows the formation of ions.
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which statement is true about a polyatomic ion? it forms metallic bonds…
It is made of atoms that are covalently bonded together.
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the table lists the lattice energies of some compounds. compound lattic…
The lattice energy increases as cations get smaller, as shown by LiF and KF.
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which statement indicates that a substance may be an ionic compound? it…
It is made up of a crystal lattice.
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read shakespeares \sonnet 19.\ devouring time, blunt thou the lions paw…
A. the abab, cdcd, efef, gg rhyme scheme C. the widespread use of iambic pentameter D. the use of three quatrains followed by a couplet
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small particles of organic material are called _________. a. discharge …
C. detritus
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question 55 (4 points) note: the naming problems are hand graded so you…
$Cr_{2}(HPO_{4})_{3}$
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question 54 (4 points) give the formula for titanium (iv) cyanide. clic…
$Ti(CN)_4$
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question 53 (4 points) give the formula for vanadium (iii) hydroxide. c…
$V(OH)_3$
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question 52 (4 points) give the formula for scandium nitrate. click/scr…
$Sc(NO_{3})_{3}$
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question 51 (4 points) give the systematic name for co(hso4)3 (credit w…
cobalt(III) hydrogen sulfate
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question 50 (4 points) give the systematic name for p₂o₅ (credit will n…
Diphosphorus pentoxide
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question 49 (4 points) give the systematic name for ni(h2po3)3 (credit …
nickel(III) dihydrogen phosphite
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question 48 (4 points) give the systematic name for al(c2h3o2)3 (credit…
Aluminum acetate
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question 47 (1 point) when lithium nitride is formed from elemental li …
oxidation
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question 46 (1 point) when lithium nitride is formed from elemental li …
reduction
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question 45 (1 point) how many formula units are in li₂₁n₇? __1__ a. 0 …
B. 1
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question 44 (2 points) give the formula for the compound formed between…
D. $Li_3N$
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question 43 (2 points) which is the best explanation for why oxygen and…
A. both have 6 valence electrons
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question 42 (1 point) how many covalent bonds do oxygen and sulfur norm…
C. 2