化學
化學反應、化學計量、分子結構與元素性質。
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which of the following molecules is polar? 1. bh₃ 2. cf₄ 3. nh₃ 4. h₂ 5…
3. $NH_3$
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a venn diagram is used to compare and contrast different topics. the it…
Endothermic: ice melting into water, and an instant ice pack turning cold Exothermic: fireworks exploding, and gasoline burning
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an atom will form a chemical bond with another atom if 1. ions can be f…
2. the resulting molecule is more stable.
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which is evidence that a chemical reaction has likely occurred? a liqui…
the formation of a precipitate
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when baking soda and vinegar react, the surface bubbles. what does this…
a chemical change, because a gas is being formed
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consider the following reaction: ch₄(g) + 4cl₂(g) → ccl₄(g) + 4hcl(g) w…
$42.7\ g$
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pedro wants to create a chemical reaction between oil and water. he add…
No, because no new substances were formed.
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which is an example of a chemical reaction? paper folded into tiny piec…
paper burned and turned into smoke
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theresa creates an experiment where she mixes two red - colored substan…
A. A chemical change started immediately and finished at eight minutes.
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consider the following chemical reaction: 4 al + 3 o₂ -------> 2 al₂o₃.…
C. 75.86%
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question 1 so₂ reacts with h₂s as follows: 2h₂s + so₂ ⇌ 3s + 2h₂o when …
10.6 g of sulfur are formed.
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pure sodium metal placed in water will spark and ignite, as well as for…
Heat is produced. Light is produced. Bubbles appear.
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14. using the symbol readout box, figure out which particles affect eac…
|Position in symbol box|Term to describe this information|Particle used to determine this|How the value is determined| |----|----|----|----| |a|Chemical symbol|Protons|Based on nu…
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theo mixes cake batter and places it in the oven at 350°f for 45 minute…
Baking a cake is an endothermic reaction as it absorbs heat energy from the oven to undergo chemical changes.
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a food item that is left out of the refrigerator turns brown and forms …
C. Bubbles appear, E. The color changes
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identify the chemical reactions as endothermic, exothermic, or neither.…
- An egg cooking: Endothermic - A candle burning: Exothermic - Plaster and water combining and becoming warm: Exothermic - Salt being added to water, with no change in temperature…
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when potassium iodide liquid is poured into lead nitrate solution (both…
A precipitate forms. The color changes.
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karina strikes a match to light a candle. explain what type of reaction…
The burning match represents an exothermic reaction, where chemical energy is converted into heat and light energy.
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which indicator of a chemical reaction is shown in the picture? the for…
the formation of a gas
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2. explain what is incorrect with respect to the following set of quant…
The value of \(l = 3\) is incorrect for \(n=3\) as \(l\) ranges from \(0\) to \(n - 1\).
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identifying indicators of a chemical reaction write a description of ho…
Common indicators of a chemical reaction include color change, gas production, precipitate formation, temperature change, and odor change.
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1. what are the substances to the left of the arrow in a chemical equat…
1. The substances to the left of the arrow in a chemical equation are called reactants. 2. The substances to the right of the arrow in a chemical equation are called products. 3. …
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* please submit your answers on a separate sheet of paper. you do not n…
1. Reactants; Products; Yields or reacts to form 2. $HCl(g)$, $O_2(g)$; $H_2O(g)$, $Cl_2(g)$ 3. Makes the number of atoms of each element the same on both sides of the equation 4.…
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4. explain what is meant by the conservation of mass and how it is usef…
The conservation of mass means that in a closed - system, the total mass before and after a chemical reaction is the same because atoms are conserved. It helps scientists balance …
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1. a student was performing the test for chloride in his unknown. when …
1. No, chloride was not indicated. Chloride does not react with $HNO_{3}$ to produce bubbles. 2. No, she is not correct. Barium forms precipitates with other anions too, not just …
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write the electron configuration for a neutral atom of aluminum.
$1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}$
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use the simulation again. now go to \systems\ and create 5 different ty…
4. Chemical energy (input) to Light energy (output) 5. Electrical energy (input) to Mechanical energy (output) 6. Chemical energy (input) to Thermal and Light energy (output) 7. L…
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(a) a certain solution has a hydrogen ion concentration of 6.53×10⁻⁴ mo…
(a) $0.000653$ (b) $4.2\times 10^{5}$
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calcium - 44 contains ____ protons, ____ neutrons, & ____ electrons. a.…
A. 20, 24, 20
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how many neutrons are in the isotope carbon - 14? a. 8 b. 12.01 c. 6 d.…
A. 8
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the mass number indicates the number of ______ in an atom. a. protons b…
D. protons and neutrons
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a neutral atom has an equal number of ______ and ______. a. protons, el…
A. protons, electrons
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aluminum-27 has a mass number of ________. a. 26.982 b. 27 c. 14 d. 13
B. 27
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chlorine-37 has an atomic number of ______. a. 20 b. 35.45 c. 37 d. 17
D. 17
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the atomic number indicates the number of ______ in an atom. a. protons…
A. protons
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nitrogen-15 contains ______ protons, ______ neutrons, and ______ electr…
A. 7, 8, 7
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draw the lewis structure for the nitronium (no₂⁺) ion.
O=N=O The nitrogen atom is in the center, with double - bonds to each of the oxygen atoms. Each oxygen has two lone - pairs of electrons.
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molecular geometry made easy: vsepr the shape of a molecule to determin…
18
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multiple - choice question how many \things\ are on the central atom of…
C. 2
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lone pairs occupy more space than bonds. false true
True
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multiple - choice question how many electron domains surround the centr…
B. Four
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what type of intermolecular forces is/are present in hf? * london dispe…
E. dipole - dipole, hydrogen bonding, and London dispersion forces
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the ph scale is used to tell if a substance is an acid or base. substan…
an acid
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6. select your favorite hobby or activity. list all the items you use i…
(Answer will vary depending on the chosen hobby. For instance, if the hobby is baking: Items used are flour, sugar, baking powder. Chemistry helps in the leavening process with ba…
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what type of intermolecular forces is/are present in so3? london disper…
London Dispersion Forces only
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which of these is the most acidic? bleach apple chemicals inside a batt…
chemicals inside a battery
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which of the following is a base? baking soda vinegar lemon juice
Baking soda
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what type of intermolecular forces is/are present in c3h8? * london dis…
London Dispersion Forces only
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what type of intermolecular forces is/are present in tecl4? london disp…
C. London Dispersion forces and dipole - dipole forces
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the ph scale how is pure water (in between the red and blue boxes with …
It is neither an acid nor a base because it is neutral.
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write the name of the element family to which each of the elements in t…
Fluorine: Halogen Rubidium: Alkali - metal
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5. give two examples of chemistry in your everyday life
1. Cooking food (Maillard reaction). 2. Rusting of iron objects.
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the ph scale how are substances on the low end (ph 1 - 6 in the red box…
they are acids
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what type of intermolecular forces is/are present in hbr? * h——br: lond…
C. London Dispersion forces and dipole - dipole forces
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choose the correct answer. which of these are acidic? tomatoes, lemon j…
tomatoes, lemon juice, vinegar, limes
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4. drug testing of athletes and other individuals is big business. comp…
4. Bioanalytical chemistry 5. One example is cooking. Chemical reactions occur when we cook food, like the Maillard reaction which gives browned food its flavor. Another example i…
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here are four sketches of substances. each sketch is drawn as if a samp…
Substance Z: compound Substance X: compound Substance T: mixture Substance Y: element
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what do acids taste like? bitter sour
sour
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what type of intermolecular forces is/are present in ch3br? * london di…
C. London Dispersion forces and dipole - dipole forces
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3. some chemists are interested in studying the rates of chemical react…
Physical Organic chemistry
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question 43 the word part atelo - means: o incomplete o arteriole o blo…
- Question 43: incomplete - Question 44: decrease in normal RBC numbers, iron, or hemoglobin levels - Question 45: embolism
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which of these do bases release in water? hydroxide ions (oh -) hydroge…
hydroxide ions (OH-)
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what type of intermolecular forces is/are present in br2? br2 :br - br:…
London Dispersion Forces only
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choose the correct answer. which of these do acids release in water? hy…
hydrogen ions (H+)
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2. enzymes are large molecules that are present in most living things a…
Bioanalytical chemistry
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how many protons and neutrons are in an atom of k - 39? number of proto…
Number of protons = 19 Number of neutrons = 20
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what type or types of intermolecular forces exist or exists in the mole…
A. London Dispersion forces only
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here are four sketches of pure substances. each sketch is drawn as if a…
Substance A: compound Substance B: compound Substance C: element Substance D: compound
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what type or types of intermolecular forces exist or exists in the mole…
London Dispersion forces, dipole dipole, & H bonding
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what type or types of intermolecular forces exist or exists in the mole…
London Dispersion forces & ionic bonding
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1. what produces the sensation of sound? 2. what is ultrasound? 3. what…
1. Vibrations. 2. Sound waves with frequencies above 20,000 Hz. 3. A material that can return to its original shape after being deformed and transmit mechanical waves; air, water,…
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what type or types of intermolecular forces exist or exists in the mole…
London Dispersion forces & dipole dipole
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here is a graph of the molarity of butyl chloride (c₄h₉cl) in a reactio…
Is $C_4H_9Cl$ being created or destroyed by the chemical reaction? destroyed If $C_4H_9Cl$ is being created or destroyed, what is the rate at which it is being created or destroye…
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what type or types of intermolecular forces exist or exists in the mole…
London Dispersion forces & dipole dipole
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what type or types of intermolecular forces exist or exists in the mole…
London Dispersion forces only
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what type or types of intermolecular forces exist or exists in the mole…
A. London Dispersion forces only
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what type or types of intermolecular forces exist or exists in the mole…
A. London Dispersion forces only
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question 3 determine if the following is an element, molecule, compound…
Both
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what type or types of intermolecular forces exist or exists in the mole…
D. London Dispersion forces, dipole dipole, & H bonding
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question 2 1 pts determine if the following is an element, molecule, co…
A. Molecule
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question 1 ischemia of the myocardium may result in: aneurysm angina pe…
- Question 1: angina pectoris - Question 2: smoking, obesity, lack of exercise, and hyper/cholesterol/emia - Question 3: apoplexy
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what type or types of intermolecular forces exist or exists in the mole…
A. London Dispersion forces only
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answer the following. (a) a certain solution has a hydrogen ion concent…
(a) $4.48\times 10^{-5}$ (b) $47000$
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what type or types of intermolecular forces exists or exist in the mole…
A. London Dispersion forces only
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classify as polar or nonpolar. ch3cl * polar molecule nonpolar molecule…
polar molecule
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classify as polar or nonpolar. so2 * polar molecule nonpolar molecule
polar molecule
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classify as polar or nonpolar. co2
Nonpolar molecule
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here is a graph of the pressure of oxygen (o₂) in a reaction vessel dur…
1. O₂ is being destroyed. 2. - 0.025 atm/s 3. - 0.017 atm/s
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¿cuál es el segundo número cuántico de uno de los electrones en el subn…
D. $l = 1$
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según el diagrama de fases del h2o ¿qué sucede con las fases del agua a…
# Explicación breve: Al observar el diagrama de fases del agua a 0 °C, cuando la presión aumenta de 0 atm a 10 atm, el agua pasa de estado gaseoso (vapor de agua) a estado sólido …
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¿qué es un alqueno? a. un hidrocarburo que contiene todos los enlaces s…
A. Un hidrocarburo que contiene todos los enlaces simples
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¿en qué diferencias se basa la cromatografía para separar partes de una…
B. Diferentes tamaños moleculares
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¿cuál de los siguientes es un ácido carboxílico? a. h - c - c - c - c =…
# Explicación breve: Un ácido carboxílico tiene la estructura funcional -COOH. Analizando las estructuras dadas, solo la opción D tiene el grupo -COOH. # Respuesta: D. H - C - C -…
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¿qué se sabe sobre una reacción con entalpía positiva? a. se desprende …
B. Se requiere calor para que se produzca la reacción.
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¿qué caracteriza una reacción ácido - base de arrhenius? a. forma una s…
A. Forma una sal y agua.
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¿en qué condiciones se encuentra?δ¿g para una reacción siempre positiva…
D. Cuando $\Delta H$ es positivo y $\Delta S$ es negativo
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¿qué es un ácido débil? a. un ácido que ha sido diluido con agua. b. un…
# Breve explicación: Los ácidos débiles son compuestos químicos que no se disocian completamente en una solución acuosa. Un ácido diluido no es lo mismo que un ácido débil. Los ác…
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¿qué describe mejor lo que indica el número de ph sobre una solución? a…
DO. ¿Qué tan ácida es la solución?
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¿qué es un sólido iónico? a. un sólido cristalino unido por enlaces cov…
# Breve explicación: Los sólidos iónicos son sólidos cristalinos formados por iones positivos y negativos unidos por fuerzas de atracción electrostática (atracciones de carga). La…
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9. if you want a darker stain, what can you do after the first coat dri…
9. Apply a second or additional coat. 10. Oil - based and water - based stains. 11. Advantage: better durability and richer color; Disadvantage: longer drying time and stronger od…