化学
化学反应、化学计量、分子结构与元素性质。
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when the equation below is balanced using the smallest whole number coe…
b 8
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the stinky durian fruit the durian is an asian fruit that is known for …
Scientists found that a combination of different chemicals is responsible for the durian's powerful odor.
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balance the following chemical equation: fe(oh)3→fe2o3+h2o
\(2Fe(OH)_3 = Fe_2O_3+3H_2O\)
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fill in the missing coefficients to balance the chemical equation below…
The coefficient of \(NH_3\) is \(4\) and the coefficient of \(O_2\) is \(5\).
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balance the following chemical equations: li + o2 → li2o
\(4Li + O_2 = 2Li_2O\)
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balance the following chemical equations: al₂o₃ + hcl → alcl₃ + 3h₂o
\(Al_2O_3 + 6HCl=2AlCl_3+3H_2O\)
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identify the coefficient and the subscript in the formula 3h₂. a h coef…
b. H coefficient is 3, and the subscript is 2.
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which group of coefficients balances the following chemical equation? 2…
a = 2, c = 3. So the correct group of coefficients is when \(a = 2\) and \(c=3\) (assuming the option with \(a = 2\) and \(c = 3\) is present among the choices. If we consider the…
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the phase diagram for methane shows a triple point at 90.7k and 0.115 a…
4. Liquid
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which of the following statements regarding intermolecular forces (imf)…
7. III only
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5. mlib 64 5109 10 pts possible the process of water freezing to form i…
1. an exothermic phase change.
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consider the phase diagram for water. how is the pt phase diagram for w…
1. La pendiente de la fase transición entre sólido y líquido es negativa.
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what is the activation energy for the forward reaction in the diagram b…
5. \(45\ kJ\cdot mol^{-1}\)
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3. lde rxn coordinate diagram 002 10 pts possible what is the activatio…
1. \(25\space kJ\cdot mol^{-1}\)
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the process of steam condensing to form liquid water is 1. an exothermi…
1. an exothermic phase change.
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which statement is false? 1. in the absence of a phase change, the visc…
2. All other factors being equal, if adhesive forces are strong, capillary action is likely to occur less readily than if adhesive forces are weak.
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question 9 of 10 two atoms have the same number of protons but a differ…
B. isotopes.
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question 2 of 10 which of the following correctly compares the phosphor…
C. \(^{31}\text{P}\) has 16 neutrons, whereas \(^{32}\text{P}\) has 17 neutrons.
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which piece of safety equipment should be used if chemicals get into a …
Eyewash station
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this study was about how people think others perceive them. consider a …
self - fulfilling prophecy
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3 what makes a change a chemical change instead of a physical one? a th…
B. The atoms rearrange to form a new substance
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3 what makes a change a chemical change instead of a physical one? a th…
B. The atoms rearrange to form a new substance
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in one to two sentences, explain a similarity and a difference between …
Similarity: Particles in both have same kinetic energy (same temp). Difference: Liquid water particles are closer; steam particles are more spaced out.
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which statement is a good description of plastic? (1 point) it is a syn…
It is a synthetic material that comes from natural resources.
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which phases does water go through if you use distillation to separate …
from a liquid to a gas, and back to a liquid
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a beaker contains a mixture of sand and salt. a student adds water to d…
filtration to collect the sand and distillation to collect the salt
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synthetic materials, natural resources quick check how is plastic made?…
Oil and natural gas are chemically broken down into small compounds that combine to form plastic.
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synthetic materials, natural resources quick check what is a polymer? (…
C. a chain of repeating compounds found in both natural and synthetic materials
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synthetic materials, natural resources quick check what must happen for…
It needs to go through a chemical reaction.
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a beaker contains a mixture of sand and salt. a student adds water to d…
filtration to collect the sand and distillation to collect the salt
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you are worried that a solid substance has dissolved in a beaker of wat…
Boil the water away, leaving the substance behind in the beaker.
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separating mixtures quick check which property could allow a student to…
magnetism
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a scientist is working in a lab and accidentally combines two liquids t…
heating the liquids and letting one boil away first
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determine the final temperature of a 37.53 ml salt solution initially a…
59.31
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what is the final temperature of an ingot of pure nickel with a mass of…
65.6
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question 7 1 pts in the wise words of dan gable, an olympic gold medali…
\(0.312\)
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carbon tetrachloride, ccl4, was once a popular solvent in organic chemi…
19.41
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iron(iii) oxide is formed when pure iron reacts with oxygen according t…
\(-44.28\)
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question 3 1 pts when gaseous phosphorus pentachloride, pcl₅, is heated…
1 \(PCl_{5}(g)\) → 1 \(PCl_{3}(g)\) + 1 \(Cl_{2}(g)\); \(\Delta H=+87.9\) kJ
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when gaseous phosphorus pentachloride, pcl₅, is heated to moderate temp…
\(-650.0\)
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when 64.5 g of potassium chlorate is dissolved in water, 21.78 kj of en…
- First question: Endothermic - Second question: Molar Enthapy, kJ/mol; Temperature
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scene 2: outside the school - near a stream zara: hey, guys. im testing…
1. Copper can poison aquatic life and harm the environment even in small amounts. 2. Recycle old electronics, avoid pouring chemicals down the drain, and support clean mining prac…
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alex: wait—why copper? riley: copper is a great conductor. it lets elec…
1. Copper is used in electronics because it is a great conductor. It allows electricity to flow easily. 2. Copper chloride is formed when copper reacts with certain chemicals. It …
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the diagrams below show two pure samples of gas in identical closed, ri…
neither; their gas pressures are the same
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2. juan is in graduate school studying biochemistry, which means that h…
paraphrasing
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what kind of change is this? physical chemical pap-porrial
chemical
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the diagrams below show three pure samples of gas in identical closed, …
gas B, gas A, gas C
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scientific inquiry. select the part of the passage that describes devel…
Dustin thought that the diameter of the container shouldn't matter; it is the ingredients themselves that determine the height of the foam.
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the passage below describes a process of scientific inquiry. select the…
So Simon got nine identical cans of soda. After opening them, he left three in the refrigerator, three on the kitchen counter, and three outside in the hot sun. Five hours later, …
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the passage below describes a process of scientific inquiry. select the…
Finding that the crushed tablets had dissolved quicker than the whole ones, she concluded that her dad was correct.
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the passage below describes a process of scientific inquiry. select the…
Sofia now predicted that citric acid was more effective than sugar at preserving lemonade's color and freshness.
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the passage below describes a process of scientific inquiry. select the…
He found that the rock candy made with white sugar had larger crystals than those made with pure cane sugar.
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the passage below describes a process of scientific inquiry. select the…
Layla already knew that ice floats to the top of water because ice is less dense, so she reasoned that liquids must get less dense when they freeze.
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the front of a house on a snowy day on a cold winter morning, clare ope…
If they were both out in the same temperature, why did one feel colder?
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the passage below describes a process of scientific inquiry. select the…
She concluded that mineral spirits are the best cleaner for oil paints since they are both nonpolar.
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this passage describes a chemical reaction. read the passage. then, fol…
| Substance | Reactant | Product | |--|--|--| | aluminum (Al) | ✔️ | | | aluminum oxide (Al₂O₃) | | ✔️ | | ferric oxide (Fe₂O₃) | ✔️ | | | iron (Fe) | | ✔️ |
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this passage describes a chemical reaction. read the passage. then, ans…
soda ash (\(Na_2CO_3\)), calcium chloride (\(CaCl_2\))
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9. justify why the number of valence electrons stays the same within a …
A. valence electrons; B. full valence shell
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note: to answer some of the questions, it may help to reference a perio…
\(2H_2(g)+O_2(g)\to 2H_2O(l)\) (the third option)
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its time for the unit exam. this is your opportunity to show how much y…
\(2,1,2\)
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drag the tiles to the correct boxes to complete the pairs. identify the…
- Water breaks down into hydrogen and oxygen: decomposition - Leaves make starch using chlorophyll and carbon dioxide: synthesis
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in addition to having a unique name and atomic number, every chemical e…
The atomic symbol \(Ni\) represents the chemical element \(nickel\).
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the diagram below is a model of two solutions. each ball represents one…
Solution B
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the diagram below is a model of two solutions. each pink ball represent…
Solution B
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the diagram below is a model of two solutions. each blue ball represent…
Solution B
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some chemical compounds are listed in the first column of the table bel…
- \(HC_2H_3O_2\): molecular, weak acid - \(NaBr\): ionic - \(NH_3\): molecular, weak base - \(KOH\): ionic, strong base
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the chemical formulae of some acids are listed in the first column of t…
| acid | strong or weak? | species present at \(10^{-6}\text{ mol/L}\) or greater when dissolved in water | | ---- | ---- | ---- | | \(HBrO_4\) | strong | \(H^{+},BrO_4^{-}\) | | …
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which statement is true about all the atoms of a given element? a they …
d. They all have the same number of protons.
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pregunta 6 (4 puntos) (01.06 mc) what type of solution contains more so…
d. Supersaturated
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pregunta 5 (4 puntos) (01.06 mc) during an experiment, iron powder and …
d. Iron powder and sulfur powder combined physically, therefore they retained their individual properties.
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pregunta 4 (4 puntos) (01.06 mc) what process would best separate a sol…
C. Distillation, because these liquids evaporate at different temperatures
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pregunta 3 (4 puntos) (01.06 mc) what type of mixture is chicken noodle…
b. A heterogeneous mixture, because the different components are mixed unevenly within the substance
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pregunta 2 (4 puntos) (01.06 lc) which of the following correctly descr…
B. The atoms have no set ratio for how the atoms can combine, and they are not chemically bonded together.
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steel is an example of a pure substance because it is made up of two di…
b. False
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pregunta 13 (1 punto) (01.06 mc) the contents of two petri dishes are d…
b. The final substances in both petri dishes are pure substances.
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pregunta 12 (1 punto) (01.06 lc) which of the following is a property o…
A. It can be chemically separated if it is a compound.
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pregunta 11 (1 punto) (01.05 hc) in science class, the teacher, mr. phi…
B. This is correct because the ice only changed phases, not composition.
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pregunta 10 (1 punto) (01.05 mc) while modeling a volcano using two sub…
C. Chemical change, because bubbling and fizzing indicate production of a gas, which is a new substance
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pregunta 9 (1 punto) (01.04 mc) a student wants to examine a substance …
a. Ductility, because it can be observed by altering the shape of the substance
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pregunta 8 (1 punto) (01.04 lc) the following properties are either phy…
B. Flammability
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pregunta 7 (1 punto) (01.04 mc) in making a phase transition from a liq…
b. Energy must be added, particles must move faster
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pregunta 6 (1 punto) (01.04 mc) the table shows the range of the amount…
a. \( P > R > Q \)
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pregunta 5 (1 punto) (01.04 lc) this state of matter is characterized b…
A. Gas
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(01.01 lc) which of these statements best explains why chemistry is tes…
A. It can measure data by experiments.
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pregunta 11 (5 puntos) (02.03 mc) calcium (ca) has an atomic number of …
A. \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\)
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the diagram shows four different locations in an atom. which locations …
a. 1 and 4
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pregunta 8 (5 puntos) (02.02 mc) which of the following groups of eleme…
A. Actinides
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pregunta 7 (5 puntos) (02.02 lc) a neutral oxygen atom has ______ elect…
B. 8
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pregunta 6 (5 puntos) (02.02 lc) ________ is a metalloid in the periodi…
A. Arsenic
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(02.01 lc) which of the following provides evidence to support rutherfo…
A. Gold foil experiment
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the three types of energy hank is categorizing things into include all …
mass
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pregunta 4 (4 puntos) (03.06 mc) what is the strongest intermolecular f…
D. London dispersion
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pregunta 3 (4 puntos) (03.06 lc) what type of intermolecular force occu…
A. Dipole - dipole force
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pregunta 2 (4 puntos) (03.06 mc) consider the molecules h₂o, h₂s, h₂se,…
a. \(H_2O\), because it experiences hydrogen bonding.
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pregunta 1 (4 puntos) (03.06 lc) an instantaneous dipole occurs when a …
a. True
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(04.01 mc) a chemical equation is shown: c₂h₄ + o₂ → co₂ + h₂o accordin…
C. 6
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pregunta 4 (3 puntos) (04.01 mc) which of the following laboratory proc…
C. Heating 32 g of S and 56 g of Fe to produce 88 g of FeS and unused reactants
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pregunta 3 (3 puntos) (04.01 mc) for the reaction ( nh_3 + no \to n_2 +…
C. Reactants: \(4NH_3\) and \(6NO\); products: \(5N_2\) and \(6H_2O\)
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pregunta 2 (2 puntos) (04.01 lc) fill in the blank with the correct num…
2
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pregunta 1 (3 puntos) (04.01 lc) match each term to a correct example f…
1. \( B_2 \) corresponde a **b. Reactant** (es un reactivo). 2. \( AB \) corresponde a **a. Product** (es un producto). 3. \( 2 \) corresponde a **c. Coefficient** (es un coeficie…