化學
化學反應、化學計量、分子結構與元素性質。
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6. atoms with the same number of protons but different number of neutro…
Isotopes
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1 which represents a chemical reaction? (1 point) hydrogen burning stea…
1. A. hydrogen burning 2. C. A substance that cannot be broken down
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4. what part of the element does the \8\ refer to in the diagram? 8 o o…
The atomic number
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which term is defined as the energy required to remove an electron from…
D. ionization energy
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which option is an example of a chemical property? color density reacti…
C. reactivity
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which option is an example of a chemical property? o density o color o …
ability to decompose
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what conditions can result in secondary gout? please select your answer…
D. All of the above
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which option is an example of a physical property? ph flammability free…
freezing point
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which option is an example of a physical property? flammability toxicit…
melting point
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which properties do not change the composition of a substance? physical…
physical properties
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question 5 1 pts a chemical reaction that has a positive δg is best des…
A. endergonic
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definition: attraction formed between atoms when they share electrons. …
Covalent bonds are the attraction formed between atoms when they share electrons, enabling atoms to reach a stable electron - configuration. Examples include the double - bond in …
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question 2 1 pts which of the following is an example of potential rath…
a molecule of glucose
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choose the best answer. how are ionic bonds formed? a electrons are tra…
A. Electrons are transferred between atoms
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question 1 1 pts a system in chemical equilibrium ... consumes energy a…
can do no work.
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definition: charged particle that has either more or fewer electrons th…
A. negative
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read the first two stanzas of the poem. which rhyme scheme is used, and…
B. AABB - It creates a steady, musical rhythm similar to jazz.
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analyze the two models below. model a model b which statement explains …
A. Model A, because the particles are uniformly mixed together.
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separating mixtures 7. in general, what is used to separate mixtures? d…
7. Various methods based on physical properties. 8. Filtration. In filtration, a heterogeneous solid - liquid mixture is poured through filter paper, with liquid passing through a…
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entropy is a measure of the kinetic energy in the random movement of mo…
a measure of the disorder or energy dispersal in a system.
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four different liquid compounds in flasks at 20°c are represented above…
C. The strength of the intermolecular forces between the particles in the liquids
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substance normal boiling point hf 293 k f₂ 85 k the electron cloud of h…
D. Liquid $F_2$ has weak dispersion force attractions between its molecules, whereas liquid HF has both weak dispersion force attractions and hydrogen bonding interactions between…
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the diagram above is a molecular model of a gaseous diatomic element th…
D. It does not show how the temporary fluctuating dipoles of the molecular electron clouds result in a net force of attraction between the molecules.
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an equimolar mixture of n₂(g) and ar(g) is kept inside a rigid containe…
D. 2.25 atm, because doubling the number of moles of Ar doubles its partial pressure.
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diagram 1 above shows equimolar samples of two gases inside a container…
C. The partial pressure of each gas in the mixture is half its initial pressure; the final total pressure is half the sum of the initial pressures of the two gases.
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a gas mixture at 0°c and 1.0 atm contains 0.010 mol of h₂, 0.015 mol of…
C. About 0.20 atm, because $H_2$ comprises 20% of the total number of moles of gas.
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the graph above shows the distribution of molecular speeds for four dif…
D. The molecular masses of the gases, because the gas molecules have the same average kinetic energy and mass can be calculated using the equation $KE_{avg}=\frac{1}{2}mv^{2}$.
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a 1 l sample of helium gas at 25 °c and 1 atm is combined with a 1 l sa…
D. The average kinetic energy of the helium atoms and neon atoms do not change when the gases are combined.
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the structure of one form of boron nitride is represented above. this f…
B. Boron nitride is a network solid of atoms connected by covalent bonds with fixed bond angles.
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2 mark for review the ionic compounds nacl and mgs are represented by t…
Diagram 1 represents $NaCl$, and $NaCl$ has the lower melting point because it has ions with lower charges ($Na^+$ and $Cl^-$ with + 1 and - 1 charges respectively) compared to $M…
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which of the following is not found on a veci label? a. engine family a…
C. Gross vehicle weight
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which statement best helps to explain the observation that nh₃(l) boils…
C. $NH_3$ has hydrogen bonding that is stronger than the dipole - dipole forces in $PH_3$
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name per date chemistry writing & classifying mixtures class activity a…
1. **Answer**: True. Most samples of matter in our daily - life are mixtures. For example, air is a mixture of nitrogen, oxygen, carbon - dioxide and other gases; ocean water is a…
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name per date chemistry visiting & classifying mixtures class activity …
1. True. Most everyday substances are mixtures, e.g., air. 2. A combination of two or more substances not chemically combined, separable by physical means, e.g., sand - water mixt…
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name per date chemistry visiting & classifying mixtures class activity …
1. # Brief Explanations: Most samples of matter we encounter in daily[SSE Completed, Client Connection Error][SSE Completed, Client Connection Error][LLM SSE On Failure]
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12 what is the difference between an element and a compound?
An element consists of one - type of atom and is indivisible chemically. A compound is made of different elements combined chemically in a fixed ratio and can be decomposed chemic…
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in a lab, the temperature of various chemical reactions is changing by …
$4 + dm$
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20. what does the acronym chnops stand for? carbon, hydrogen, sulfur, p…
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur.
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11. explain why the properties of a pure substance do not vary from sam…
The properties of a pure substance do not vary from sample to sample because a pure substance has a fixed and definite composition. All samples are made up of the same type of ato…
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select the correct answer from each drop - down menu. 2naoh + h₂so₄ → n…
The equation is un - balanced because the number of hydrogen atoms and oxygen atoms is not equal in the reactants and in the products. After balancing, the equation is $2NaOH + H_…
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25-26 unit 1 assessment physical science s8p1a-f which of the following…
Elements can combine into compounds with new properties.
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answer the questions in the table below about the shape of the triiodid…
How many electron groups are around the central iodine atom? 5 What phrase best describes the arrangement of these electron groups around the central iodine atom? Trigonal bipyram…
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30. design a concept map that summarizes the relationships among matter…
Matter |-- Pure Substances | |-- Elements | |-- Compounds |-- Mixtures | |-- Homogeneous Mixtures | |-- Heterogeneous Mixtures
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answer the questions in the table below about the shape of the nitrosyl…
How many electron groups are around the central nitrogen atom? 3 What phrase best describes the arrangement of these electron groups around the central nitrogen atom? Trigonal pla…
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answer the questions in the table below about the shape of the borate (…
How many electron groups are around the central boron atom? 3 What phrase best describes the arrangement of these electron groups around the central boron atom? Trigonal planar
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select the correct boxes. which two elements have the same number of va…
Silicon, Carbon
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29. describe the separation technique that could be used to separate ea…
a. Distillation b. Filtration c. Manual separation
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to determine whether a chemical reaction has taken place, a scientist c…
A. density
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select all the correct answers. copper is listed in the 29th position i…
A. a metal E. an element
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select the correct answer. which chemical reaction absorbs energy? a. p…
A. photosynthesis
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drag the tiles to the correct boxes to complete the pairs. identify the…
methane + oxygen → water + carbon dioxide + heat: combustion reaction of fossil fuels glucose + oxygen → carbon dioxide + water + energy: respiration water + carbon dioxide + sunl…
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assignment: key terms in chemistry name: celianyu scharaga date: 10/3/2…
1. liquid, solid 2. flammability 3. chemical reaction 4. density 5. gas 6. reactant 7. state of matter 8. product 9. states of matter 10. chemical reaction
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select the correct answer. darryl finds a bottle of what looks like cle…
C. heterogeneous mixture
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14) explain the 2 steps to measure the ph level of a substance. your an…
1. Prepare sample and indicator. 2. Observe and read the result.
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drag each label to the correct image. each label can be used more than …
Lemon juice: acidic Salt solution: neutral Baking soda: alkaline
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4 mixtures of matter (continued) check your progress 27. classify each …
a. Homogeneous mixture b. Homogeneous mixture c. Heterogeneous mixture
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12.) which of the following does ph not measure? * the acidity of a sub…
12. The number of electrons in a substance 13. 1
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choose the image where a chemical reaction has not taken place.
The image of water waves or the image of plant leaves (assuming there are such images not fully shown in the provided partial picture but they would be the correct ones as they do…
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the sudden earthquake was a ______, destroying homes and infrastructure…
1. B. cataclysm 2. C. imperative
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unit 2 - lec 3 hw - mole conversions 1 mol = 6.02 x 10²³ atoms (\\frac{…
1. $4236\ mol$ 2. $1.806\times 10^{25}\ atoms$ 3. $2.709\times 10^{23}\ atoms$ 4. $12.96\ mol$
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sequence the steps (1 - 4) of separating a mixture of sand, salt, and i…
1. Separate the iron filings from the sand and salt by using a magnet. Physical property used: Magnetism of iron. 2. Mix the sand and salt mixture with water. Physical property us…
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unit 2 - lcc 3 hw - mole conversions 1 mol = 6.02 x 10^23 atoms (1 mole…
4236 mol 2.
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select the correct answer from each drop - down menu. steel is an alloy…
First drop - down menu: iron and carbon Second drop - down menu: stronger
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select the correct answer. in this equation, stands for carbon, stands …
D. \(2CO + 2NO ightarrow2CO_{2}+N_{2}\)
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4) ____ is the amount of energy needed to start a chemical reaction. * …
4. B. Activation energy 5. A. mass 6. D. bonds
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choose the correct answer. what kinds of substances can leaching carry …
nutrients, pesticides, and potentially harmful chemicals
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complete the table. element name chemical symbol atomic number strontiu…
| Element name | Chemical symbol | Atomic number | | ---- | ---- | ---- | | strontium | Sr | 38 | | zinc | Zn | 30 |
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“the lantern path” in the quiet town at dusk, lanterns flicker on the l…
They make each image and idea stand out, giving the reader time to reflect.
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complete the table. element name chemical symbol atomic number strontiu…
| Element name | Chemical symbol | Atomic number | | ---- | ---- | ---- | | strontium | Sr | 38 |
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choose the correct answer. what is the largest component of soil by per…
mineral matter
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wounds. the chemical symbol for iodine is i. determine the number of pr…
53
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you might need: periodic table complete the table. element name chemica…
| Element name | Chemical symbol | Atomic number | | ---- | ---- | ---- | | cobalt | Co | 27 | | bromine | Br | 35 |
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select all the correct answers. which changes will increase the rate of…
Adding more oxygen to the reaction, Changing the reactants from solid form to powdered form
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you might need: periodic table complete the table. element name chemica…
| Element name | Chemical symbol | Atomic number | | ---- | ---- | ---- | | cobalt | Co | 27 |
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type the correct answer in each box. the atomic number of sodium (na) i…
15; 15
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a. ¿cuál es el porcentaje de abundancia del bromo - 81? escribe tu resp…
# Explicación: ## Paso 1: Encontrar el porcentaje de abundancia del bromo - 81 Sabemos que los isótopos del bromo son el bromo - 79 y el bromo - 81, y la suma de sus porcentajes d…
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a. ¿cuál es el porcentaje de abundancia del bromo - 81? escribe tu resp…
# Explicación: ## Paso 1: Encontrar el porcentaje de abundancia del bromo - 81 Sabemos que el bromo tiene dos isótopos importantes: bromo - 79 y bromo - 81. Si el porcentaje de ab…
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classify the sentences based on the chemical reactions they describe. w…
Decomposition reactions: - When a clam shell ($CaCO_3$) is heated, carbon dioxide ($CO_2$) is given off and a white powder, calcium oxide ($CaO$), forms. - Nitrogen pentoxide ($N_…
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1. el bromo tiene dos isótopos naturales: bromo - 79 y bromo - 81. las …
a. El porcentaje de abundancia de bromo - 79 es 49.31%. El porcentaje total de los isótopos es 100%.
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reviewing content choose the letter that best answers the question or c…
1. a. water 2. d. a mixture 3. b. suspension 4. b. flammability 5. c. wood 6. c. malleable 7. a. solid 8. d. baking a cake 9. a. reactivity 10. b. a chemical change 11. A pure sub…
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select the correct number. the equation shows neutralization of an acid…
2
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which term refers to a property that depends only on the amount of a su…
B. extensive
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name: date: q1 chemistry u1l7 unit 1 review 3. **which statement correc…
3. c. A mixture can be separated by physical means. 4. c. Consist of two or more substance 5. Distillation and fractional distillation. Distillation for large boiling - point diff…
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name: chemistry: u1l4 mixture types q1 part 3: multiple choice question…
1. C. Filtration 2. C. Boiling point 3. B. Colored pigments in ink 4. C. Evaporation 5. B. Removing water from cooked pasta 6. C. Density
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q1 chemistry. u1l7 unit 1 review prepwork: u1 review 1. *carbon dioxide…
Diagrams should be drawn as described above for carbon - dioxide and nitrogen phases with appropriate molecule arrangements and labels for each phase.
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40. how does water velocity affect chemical weathering? it slows down t…
It accelerates the transport of dissolved minerals
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analysis and questions: 1. was the mass of 20 pennies equal to 20 times…
$63.618$
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38. which factor most significantly affects frost wedging? wind velocit…
Freeze - thaw cycles
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37. how much does a chemical reaction rate typically increase for every…
It doubles
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6. name the following compound: s₄n₂ 7. name the following compound: cf…
6. Tetrasulfur dinitride 7. Carbon tetrafluoride 8. Carbon dioxide 9. Diphosphorus pentoxide 10. Sulfur trioxide
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introduction to atomic structure fausto santos what are atoms made of? …
How many Protons they have
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when you plug in a blender and make a smoothie, how is the energy trans…
The electrical energy from the blender is transformed into mechanical and sound energy.
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what type of energy transfer occurs when a helicopter is flying in the …
The chemical energy from the fuel is transformed into mechanical and sound energy.
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what are atoms made of? stated clearly nitrogen atom multiple - choice …
Neutrons, Protons
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how should all chemicals be stored? in a plastic container in the shop’…
In a clearly marked and approved container or cabinet
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schoology practice: naming covalent compounds 1. name the following com…
1. c. sulfur trioxide 2. c. tetraphosphorus decasulfide 3. c. silicon tetrachloride 4. c. Dihydrogen Monoxide 5. d. Hexabromine decafluoride
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sue was a chemistry student who liked to cook. one day she noticed that…
The addition of salt to water increases its boiling point. This causes the water to take longer to boil but also allows food to cook faster due to the higher temperature at which …
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what is the best example of chemical energy? vibrations energy stored i…
energy stored in chemical bonds
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when a person pushes a large load up an inclined plane, where does the …
Chemical energy
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while freight rail companies have recorded record multibillion - dollar…
1. C. 5.2 billion $ 2. B. 25%