Química
Reacciones químicas, estequiometría, estructuras moleculares y propiedades.
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an element has the following characteristics. • ductile • malleable • u…
C. magnesium
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question 4 of 10 what does percent composition tell you about a substan…
B. It tells you what the substance is made of.
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what is the mass of co₂ in atomic mass units? a. 22 amu b. 12 amu c. 44…
C. 44 amu
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which conversion factor would be used to convert g/mol to g/l? a. l/g b…
D. mol/L
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what are the units of molarity? a. grams/mole b. liters/mole c. grams/l…
D. Moles/liter
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what is scientific notation? a. scientific notation is a way of organiz…
C. Scientific notation is a way of writing large and small numbers.
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part a the reaction here shows a simple chemical reaction involving the…
Part A: B. 2, 7, 4, 6 Part B: C. Hydrogen atoms in ethane ($C_2H_6$) form new bonds with oxygen to form water.
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how many moles of kcl would be dissolved in 4 l of water to make a 2 m …
C. 8 moles
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material or object,observation,physical or chemical property? chalk,for…
# Explicación: ## Paso 1: Comprender la diferencia entre propiedades físicas y químicas Las propiedades físicas se pueden observar sin que cambie la composición química del materi…
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what is avogadros number? a. 6.02×10 b. 6.02×10^{-23} c. 6.02×10^{23} d…
C. $6.02\times 10^{23}$
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write a balanced chemical equation for the decomposition of solid sodiu…
D. $Na_2S(s) ightarrow2Na^+(aq)+S^{2 - }(aq)$
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as part of an experiment, a student burns propane (c3h8) to produce car…
D. $C_3H_8+5O_2 ightarrow3CO_2 + 4H_2O$
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question 2 of 10 what does molarity measure the concentration of? a. th…
C. The amount of a substance dissolved in a liquid
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sodium oxide (na₂o) can react with hydrochloric acid (hcl) to produce s…
D. 7 before and 7 after
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question 1 of 10 how many atoms does 32 g of sulfur contain? a. 6.02×10…
A. $6.02\times 10^{23}$
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the term \3 fecl₂\ in a balanced equation says a that there are three i…
C. that there are three formula units, each consisting of two chloride ions bonded to an iron(II) ion
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consider the incomplete chemical equation. co₂(g) + h₂o(l) →? assuming …
C. 20 oxygen atoms
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physical versus chemical properties it is important to remember the dif…
El cambio que happens en la tela es un cambio químico. Esto se debe a que el blanqueador reacciona químicamente con el tinte de la tela, lo que provoca una pérdida de color y un c…
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whats the verdict on vaping the smoke from regular cigarettes contains …
True
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a student draws a picture of the products and reactants of a chemical r…
D. The drawing is correct because there are 12 atoms of each type on each side of the arrow.
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question 7 of 8 which term describes this molecular shape? a. bent b. l…
C. Tetrahedral
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question 6 of 8 which molecule or ion has a bent shape? a. pcl5 b. clo4…
C. $OF_2$
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listed in the item bank are some important labels for sections of the i…
First equation: 2 Second equation: 12, 6 Third equation: 5 Fourth equation: 3 Fifth equation: 4, 7
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which of the following is an example of a chemical name using prefixes?…
D. Carbon dioxide
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question 4 of 8 how is the name of the second element in a covalent mol…
D. The ending is changed to -ide.
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6. identify give two examples of chemical properties.
# Breve explicación: Las propiedades químicas son características de una sustancia que se manifiestan durante o después de una reacción química. La combustibilidad se refiere a la…
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what is the correct formula for the compound formed by ca²⁺ and no₂⁻? a…
B. $Ca(NO_{2})_{2}$
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question 2 of 8 how does a lone pair distort the molecular shape? a. th…
D. The lone pair forces bonding atoms away from itself.
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question 1 of 8 how should you indicate that there are multiple polyato…
B. Put parentheses around the atoms in the ion and then add a subscript.
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lee and celia are lab partners. while celia pours a chemical into a gra…
Celia should stand in the safety shower while Lee tells the teacher.
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d. what do you observe when you lower the voltage to around 20 volts? e…
- d. Observation: Spectral lines become less intense and fewer types of transitions occur. Explanation: Less electron excitation due to lower voltage. - 3a. Notice: Hydrogen has m…
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which of the following elements is considered a metalloid: * he mg rn s…
1. Si 2. None of the above (as U, W, Ca, Ne are not rare - earth elements)
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name section 2 review section vocabulary boling point the temperature a…
Color, olor, densidad, punto de fusión, punto de ebullición 2.
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physical change: the physical properties change but the type of substan…
What are some examples of physical changes? Melting ice, cutting paper. The physical properties change but the type of substance: Remains the same in physical changes. There is no…
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d. group 3, period 16 3. below are 2 models for oxygen. determine the d…
The first model has a single - circle nucleus with 6 electrons around it. The second model has a two - circle nucleus and two electron - shell regions with electrons distributed b…
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examples of chemical properties reacting with oxygen (oxidation): the a…
1. burn, oxygen 2. react 3. chemical reactions
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5. usually involves the substances with another specific substance exam…
5. reaction; Reacting with Oxygen: react with oxygen; Reacting with Acids: react; Reactivity: a chemical reaction
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5. a 15.0 g - sample of a liquid has a density of 0.875 g/ml. a. what i…
a. $17.1\ mL$ b. $30.3\ g$
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student name______ class period______ date______ physical and chemical …
without
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student name class period date physical and chemical properties and cha…
1. without 2. color, density, melting - point 3. chemical reaction 4. identify 5. reaction Reacting with Oxygen: react with oxygen Reacting with Acids: react Reactivity: a chemica…
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select the text from the paragraph that best helps you understand that …
After working as a field doctor during World War I and witnessing how many soldiers died needlessly from bacterial infections, Fleming recognized the exigency of finding a chemica…
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3. why do only certain colors appear in the emission spectra of element…
3. Electrons transition between discrete energy levels, emitting photons of specific energies. 4. Single electron can make multiple transitions to different energy levels. 5. Rela…
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who was the first person to suggest all matter is made of tiny, indivis…
Democritus
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20. what is a half - life? 21. how much of a 64 mg sample of i - 123 is…
The time required for half of the atoms of a radioactive substance to decay. ### Question 21
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who was the first person to suggest all matter is made of tiny, indivis…
Democritus
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3. define the following terms and then give an example of each term. a.…
a. Definition: Anything that has mass and takes up space. Example: A book. b. Definition: A substance with a constant composition. Example: Gold. c. Definition: A substance that c…
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complete the following homework assignment. you will have 5 attempts to…
Solids have strong forces that hold the particles together. ### 2.
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7 completar el espacio en blanco 1 punto express 0.0931 in scientific n…
$9.31\times10^{-2}$ ### 8
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14. which element has the greater atomic radius? (circle) a. as or br b…
14. a. As; b. As; c. Li 15. a. Kr; b. Li; c. S 16. a. Cl; b. F; c. Mg 17. Fluorine (F) 18. Metals: Good heat/electricity conductors, malleable, ductile; lose electrons. Non - meta…
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4. at saturation, the rate at which the molecules of the solute are bei…
B. False
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atomic composition quick check which option is an isotope with 6 proton…
D. carbon - 14
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20. electrons that have the highest energy are _. valence electrons clo…
# Breve explicación: Los electrones de valencia son los electrones ubicados en la capa externa del átomo y tienen la mayor energía en comparación con los electrones de capas inter…
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atomic composition quick check a nitrogen ion has a mass of 14 and a ch…
7 protons, 7 neutrons, and 5 electrons
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atomic composition quick check which atom would be neutral? (1 point) a…
an oxygen atom with 8 electrons, 8 protons, and 9 neutrons
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atomic composition quick check how is the mass number of an atom calcul…
protons plus neutrons
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18. the force of attraction that holds two atoms together is which type…
# Breve explicación: La fuerza de atracción que mantiene dos átomos juntos es un enlace químico. Los enlaces químicos se forman a partir de la interacción entre los electrones de …
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17. what makes the group 1 elements the most reactive metals? they have…
# Breve explicación: Los elementos del Grupo 1 de la tabla periódica son metales alcalinos y tienen 1 electrón de valencia. Este electrón de valencia se puede perder fácilmente en…
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16. when are larger atoms least likely to be reactive? when they have m…
# Breve explicación: Los átomos son menos reactivos cuando tienen una capa de valencia llena. La regla de octeto establece que la mayoría de los átomos buscan tener 8 electrones e…
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12. give two examples for energy transformation in your everyday life.
1. In a light - bulb, electrical energy is transformed into light and heat energy. 2. In a car engine, chemical energy from fuel is transformed into mechanical energy.
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5. an object has a mass of 57.7 grams and occupies a volume of 21.65 cm…
### 5. # Explicación: ## Paso 1: Recordar la fórmula de densidad La densidad ($ ho$) se define como $ ho=\frac{m}{V}$, donde $m$ es la masa y $V$ es el volumen. Dados $m = 57.7\ g…
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15. which particles in an atom are in the nucleus? protons and neutrons…
# Breve explicación: En un átomo, los protones y neutrones se encuentran en el núcleo. Los electrones giran en orbitales alrededor del núcleo, y los iones son átomos cargados que …
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14. what is the greatest number of valence electrons an atom can have? …
C. 8
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12. what is the smallest particle that can be called an element? proton…
D. atom
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11. which occurs whenever valence electrons are shared or transferred b…
B. A chemical reaction
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2. the density of a liquid is 0.739 g/ml. what is the mass of 125 ml of…
### 2. # Explicación: ## Paso 1: Identificar la fórmula La fórmula de la densidad es $ ho=\frac{m}{V}$, donde $ ho$ es la densidad, $m$ es la masa y $V$ es el volumen. Re - arregl…
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10. what is a mixture? two or more things that are in the same place th…
D. Two or more things that are in the same place but not chemically combined
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9. which is a column running up and down in the periodic table? cluster…
C. family
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8. if atoms of a halogen nonmetal (group 17) gain one electron, how man…
# Explicación: ## Paso 1: Recordar la configuración de electrones de los halógenos Los átomos de halógenos en el grupo 17 tienen 7 electrones de valencia. ## Paso 2: Considerar la…
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7. all of the noble gasses have 8 valence electrons except ___. neon ar…
C. helio
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6. what is true about valence electrons? they are those electrons that …
# Explicaciones breves: Los electrones de valencia son los electrones ubicados en la capa externa del átomo, es decir, los más alejados del núcleo. Estos electrones son los que pa…
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5. what is matter? only those things that are either a solid or a liqui…
Only those things that have mass and take up space.
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4. which of the following statements is a part of john daltons atomic t…
All elements are composed of atoms that cannot be divided.
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5. define the term isotope. 6. draw the energy level diagram for each i…
5. Atoms of the same element with same protons but different neutrons. 6. Cannot draw diagrams in text, but electron in n = 1 for all hydrogen isotopes. 7. Sub - script: Atomic nu…
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1. what is a substance made of two or more elements that are chemically…
D. compound
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question 13 (5 points) air is a(n) heterogeneous mixture. element. comp…
Question 13: D. homogeneous mixture Question 14: B. energy
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which one of these would be considered an investigation? a measuring th…
A. Measuring the pH of common household chemicals., B. Observing the effects of different track surfaces on the speed of a go - cart., C. Investigating the effects of different am…
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question 11 (5 points) which one of the following substances will float…
Question 11: balsa wood (density = 0.16 g/mL) Question 12: 424
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when solid ice cream becomes a liquid, what happens to the particles? t…
The particles gain energy and move faster.
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isotopes and average atomic mass 1. using the chart below, describe the…
1. | Name | Location in Atom | Charge | Mass (heavy or light) | |--|--|--|--| | Proton | Nucleus | Positive | Heavy | | Neutron | Nucleus | Neutral | Heavy | | Electron | Outside …
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when a solid is converted directly to a gas, the change of state is cal…
Question 7: sublimation Question 8: \(4.0\times10^{-12}\) Question 9: \(37.8\ cal\)
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question 1 (5 points) which of the following is an example of a physica…
Question 1: Grinding coffee beans Question 2: Steam at 110 °C
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question 1 of 10 ella thought that all birds could do was tweet. then h…
D. accommodation
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5. fill in the table with the correct name for each acid formula name h…
| Formula | Name | | ---- | ---- | | HI | Hydroiodic acid | | $\text{HClO}_4$ | Perchloric acid | | $\text{H}_2\text{CrO}_4$ | Chromic acid | | $\text{HClO}$ | Hypochlorous acid |…
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5. which of the following represents a molecule with one carbon atom an…
5. D. $CO_2$ 6. D. 1
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substance a and substance b are mixed together. to separate the mixture…
Substance A is rice, and substance B is sugar.
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the boiling point of water is 100°c. the boiling point of acetone is 56…
Acetone will vaporize from the mixture before water.
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which method separates components of a mixture according to how quickly…
D. chromatography
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1. when sugar is dissolved into a glass of water, what is the solute? 2…
1. Sugar 2. C. element 3. C. solution 4. 2
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mixtures quick check which method of separation would be most appropria…
distillation
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what is weathering? what is mechanical weathering? what is chemical wea…
Weathering: The breakdown of rocks, soil, and minerals by contact with the Earth's atmosphere. Mechanical Weathering: Physical breakdown of rock into smaller pieces by processes l…
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mixtures quick check filtration is useful for separating: (1 point) sol…
solids from liquids or gases
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physical vs. chemical change quick check which comparison of the educat…
Physician assistants require a lower degree because they act under the close supervision of a doctor.
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physical vs. chemical change quick check which term best describes a mi…
heterogeneous mixture
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physical vs. chemical change quick check while camping, you make a snac…
The toasting of the marshmallow is a chemical change.
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physical vs. chemical change quick check why is it difficult to classif…
Some substances keep the same molecular structure when they break down, and others do not.
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physical vs. chemical change quick check which property of matter is an…
mass
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6. in the chemical equation shown, what are the reactants? 4 al + 3 o₂ …
C. Al and O₂
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construct the chemical structure of deoxyadenylic acid. drag the approp…
To accurately answer, we would need to know the specific labels and their correct placement areas. But in general, you would drag the deoxyribose sugar structure, the adenine base…
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which of the following is an allusion? when i won the science fair i wa…
Professor Anderson is such a Scrooge.
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7. sep use models you run an experiment in which two substances chemica…
The mass of the products in the closed - system will be greater than or equal to the mass of the products in the open - system. This is because in an open - system, some of the pr…