化学
化学反応、化学量論、分子構造、元素の性質。
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11. which of the following statements is true of hypertrichosis? a) it …
11. C. It is treated using methods such as photoepilation, electrolysis, and laser hair removal. 12. D. trichoptilosis 13. D. cutting split ends 14. C. Trichorrhexis nodosa near t…
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for each chemical formula, classify as a pure compound, pure element, o…
NaCl(aq): mixture Br₂(g): pure element S₈(s): pure element HCl(aq): mixture
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which best explains why nuclear reactions release more energy than chem…
The forces holding the nucleus together are much stronger than the forces binding electrons to atoms.
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question 2 1 pts using improved chemistry equipment in the late 1700s, …
C. conservation of mass
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write an unbalanced equation to represent the following reaction. do no…
$Al + O_2 ightarrow Al_2O_3$
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which is evidence that the single replacement reaction shown below is a…
Silver is in a compound as a reactant, but is a pure element as a product.
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sections 3.1 & 3.2 the atom question started: oct 8 at 1:17pm quiz inst…
B. cannot be broken down further
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how does the movement of molecules inside a solid block of iron change …
The molecules move faster.
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silicon (si) exists in earths crust as sio₂. calculate the percent comp…
The percent composition by mass of O in $SiO_{2}$ is 53.26% and of Si is 46.74%.
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barium nitrate has the formula ba(no₃)₂. which statement is true about …
Each molecule contains six oxygen atoms.
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calculate the molecular mass or formula mass (in amu) of each of the fo…
N₂O: 44.02 amu NO₂: 46.01 amu
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2) scientists used to believe that chemical reactions fueled the sun. w…
2) Initially, chemical reactions were thought to fuel the sun due to their known energy - releasing nature. We now think nuclear fusion powers the sun as it can sustain the sun's …
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a student thinks that halogens are highly reactive because their electr…
Halogens tend to attract electrons when bonding.
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molecules on an acid - base indicator react chemically with ions in a s…
C. Hydrogen ions
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a solution has a ph of 2.4. what happens to the solution if the hydroni…
The pH decreases.
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how many electrons does phosphorous (p) need to gain to have a stable o…
C. 3
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part v. life on moons? using habitability of natural satellites - ident…
1. Europa (Jupiter) - Has a subsurface ocean of liquid water beneath its icy crust, which is a key ingredient for life as we know it. Water can provide a medium for chemical react…
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question 19 (multiple choice worth 3 points) (06.06r mc) which event al…
D. Transmutation
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directions: below are the essay questions on your test. please prepare …
1. The reaction $_{86}^{219}Rn ightarrow_{84}^{215}Po+\alpha$ is an alpha - decay and is balanced because the atomic number and mass number are conserved. 2. Scientists now think …
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convert moles to grams in each of the following: 11. 1.5 moles nh₃ n: 1…
11. 25.6 g 12. 63.8 g 13. 172 g 14. 106 g 15. 103 g 16. 100 g
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question 17 (multiple choice worth 3 points) (06.03r mc) why can the su…
The space between the sun and Earth contains almost no matter.
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question 16 (multiple choice worth 3 points) (06.01r lc) which molecule…
B. $Al(OH)_3$
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what is the difference between a neutralization reaction and a double -…
C. Neutralization reactions always produce water and a salt.
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why do chemical reactions not produce radioactive particles? chemical r…
Only electrons are involved in chemical reactions.
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(06.06r mc) which would you most expect to be an unstable atom? a carbo…
D. A curium (Cm) atom with 96 protons and 85 neutrons
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a student dips a strip of metal into a liquid. which is evidence that o…
The metal bends more easily.
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a physical science student is describing the characteristics of endothe…
C. Example is photosynthesis.
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calculate the molar mass for each of the following molecules: 1. koh k …
1. 56.11 g/mol 2. 76.0 g/mol 3. 223.1 g/mol 4. 452.8 g/mol 5. 0.499 mol 6. 3.499 mol 7. 1.509 mol 8. 0.456 mol 9. 3.734 mol 10. 1.505 mol
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question 10 (multiple choice worth 3 points) (06.02r mc) which is proof…
In a synthesis reaction, two reactants combine to form a new compound.
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how does increasing the temperature generally affect the rate of a chem…
It increases the rate of the reaction.
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true or false: chemical reactions change one item into another. select …
True
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a scientist carries out a reaction twice. in trial a, the scientist com…
It will have a lower activation energy than Trial A.
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increasing the concentration and increasing the temperature both increa…
Increasing the frequency of molecular collisions
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(06.03r mc) which statement identifies a difference between endothermic…
Endothermic reactions store energy and exothermic reactions release energy.
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a chemist has two compounds that do not chemically react. he thinks tha…
A. Catalysts can only increase the rate of reaction for compounds that do react.
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a student measures the concentration of the product of a reaction over …
A. Line graph
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14. (fill - in - the - blank) the acronym ghs stands for ______ harmoni…
14. Globally 15. True 16. C. Provide PPE 17. chemical (o tóxico) 18. True 19. B. Keeping walkways clear 20. Safety
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question 2 (multiple choice worth 3 points) (06.02r mc) which reaction …
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂
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question 1 (multiple choice worth 3 points) (06.01r lc) which molecule …
Al₂(SO₄)₃
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the most widespread source of water contamination in developing countri…
A. raw sewage
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select the correct answer. identify the element from the periodic table…
Sulfur (S)
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worksheet 3 1. (multiple choice) what does ppe stand for? a. personal p…
1. A. Personal Protective Equipment 2. True 3. 1970 4. A. Falling tools 5. 85 6. True 7. A. Trench collapse 8. monthly 9. True 10. B. Shoring/shielding 11. 24 12. True 13. D. Vent…
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oxygen is perhaps the most important atom on earth. it is responsible f…
C. $n_i = 3 ightarrow n_f=2$
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1. in a nuclear reaction, which quantity is the same before and after t…
1. Total number of nucleons 2. Mass number decreases by 4, atomic number decreases by 2 3. Conserve mass - number and atomic number 4. Fusion involves nuclear change of elements, …
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periodic table high school reference sheet how many electrons are locat…
C. 3
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which of the following are true regarding this elements electron dot st…
This element has three valence electrons. This element is in period three on the periodic table.
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periodic table high school reference sheet if the hydrogen atom emits r…
C. 5
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when baking soda (solid sodium bicarbonate or sodium hydrogen carbonate…
$83.2\ g$
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periodic table high school reference sheet the state is the lowest poss…
First blank: ground Second blank: excited
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given that sulfurs atomic mass is 32.06 amu, what isotope of sulfur is …
Sulfur-32
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question 1 kente cloth, a sacred textile woven by african artists has w…
D. bright colors, with geometric designs
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48 multiple choice 1 point alcoholic beverages form when yeasts act upo…
48. B. fermentation 49. A. distillation 50. A. twice the percentage of alcohol
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which of the following are compounds that contain a covalent bond? sele…
CO, SO₂
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39 multiple choice 1 point provigil (modafinil) was recently approved f…
39. narcolepsy 40. Amphetamines are used as mostly as an adjunctive therapy. 41. ephedrine
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4. what is the formula for sodium fluoride? clear all ○ na2f2 ○ naf2 ○ …
D. NaF
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3. true or false (circle one) 1. john dalton proposed that atoms of the…
1. True 2. False
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36 multiple choice 1 point the group of psychoactive drugs called stimu…
36. C. cocaine 37. A. brand name 38. A. True
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which of the following are true for the compound cacl₂? select two corr…
It forms an ionic bond. Its name is calcium chloride.
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2. which of the following chemical formulas contains the greatest numbe…
HNO₂
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1. which of the following represents a single atom? select two correct …
Mn, I
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chemistry exit ticket: early ideas about matter name: madison clarke pe…
1. c) Antoine Lavoisier 2a. Matter is made up of tiny, indivisible particles called atoms. 2b. A compound has a fixed chemical composition and is formed by chemical reactions, whi…
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in \the author to her book\, the main reason bradstreet uses inversion …
enhance the poem's overall structure.
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when electrons are transferred between atoms, an ionic bond forms. an i…
| | Sodium atom | Chlorine atom | Sodium cation | Chloride anion | |--|--|--|--|--| | Number of valence electrons | 1 | 7 | 0 | 8 |
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12. graph the dataset below. make sure to label everything that is requ…
| Element | Atomic Number | Mass | Protons | Neutrons | Electrons | |---|---|---|---|---|---| | Chlorine - 35 | 17 | 35 | 17 | 18 | 17 | | Chlorine - 37 | 17 | 37 | 17 | 20 | 17 |…
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sodium metal (na), chlorine gas (cl₂) and table salt (nacl) have differ…
In table salt, electrons are transferred between atoms to form chemical bonds. In chlorine gas, electrons are shared between atoms to form a chemical bond.
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when two atoms with different electronegativities form a bond, the more…
When sodium and fluorine react, valence electrons are transferred between the atoms because their EN difference is greater than two. When sulfur and fluorine react, valence electr…
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when forming chemical bonds, metal atoms tend to lose electrons, while …
Nonmetal atoms tend to have higher electronegativities than metal atoms. When forming a chemical bond, atoms with low electronegativities tend to lose electrons.
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chemical bonds form when atoms share valence electrons or when one atom…
Fluorine atoms tend to gain or share electrons when forming chemical bonds: True Strontium atoms tend to lose electrons when forming chemical bonds: True Atoms with five or more v…
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because atoms in each substance are held together by a different type o…
bond in chlorine gas - electrons are shared bonds in table salt - electrons are transferred
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when forming chemical bonds, metal atoms tend to lose electrons, while …
Atoms with high electronegativities tend to gain or share electrons when forming chemical bonds. When sulfur bonds to oxygen, electrons are more strongly attracted to the oxygen a…
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6. what are isotopes? a. atoms that have the same # of electrons but di…
6. D. atoms that have the same # of protons but different # of neutrons 7. D. change the charge of an atom 8. TRUE 9. D. there are different atoms together 10. 6 g/mL
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part ii. for each of the following isotopes, write the number of proton…
| Isotope | # of Protons | # of Neutrons | # of Electrons | |--|--|--|--| | Carbon - 12 | 6 | 6 | 6 | | Carbon - 13 | 6 | 7 | 6 | | Carbon - 14 | 6 | 8 | 6 | | Chromium - 58 | 24 …
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isotopes the number of protons in a nucleus determines the identity of …
1. Isotopes of a given element have the same atomic number but a different atomic mass, meaning they have the same number of protons but a different number of neutrons. 2. The num…
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b) suppose maya spilled hydrosulphuric acid onto the counter! using you…
The teacher should use sodium bicarbonate. The products formed are sodium hydrogen sulphide, carbon dioxide and water. The balanced chemical equation is $H_2S + NaHCO_3=NaHS+CO_2 …
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2. a) three unlabeled bottles containing solutions were found in the ch…
Solution A: Sodium Chloride Solution B: Sodium Hydroxide Solution C: Hydrochloric Acid
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1. what is an element? 2. what is a compound? 3. what is a molecule?
1. A pure - substance made of one kind of atom, not breakable by chemical means. 2. A pure substance formed by chemical combination of different elements in a fixed ratio. 3. A gr…
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read the following scenario and answer the questions below. (10 marks) …
A. Mercury (II) nitrate + Sodium sulfate → Mercury (II) sulfate + Sodium nitrate B. $Hg(NO_3)_2 + Na_2SO_4 ightarrow HgSO_4+NaNO_3$ C. $Hg(NO_3)_2 + Na_2SO_4 ightarrow HgSO_4 + 2N…
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2. answer the following questions based on the balanced equation provid…
$20\ g$
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part d: balancing equations (10 marks) 01. balance the following equati…
a) 2K + Br₂ → 2KBr b) 4Al + 3O₂ → 2Al₂O₃ c) BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl d) 2HCl + Ca(OH)₂ → CaCl₂ + 2H₂O
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3. the atomic number tells you the number of ____________ in one atom o…
3. Protons; Electrons; Same 4. Atomic mass; Relative abundances 5. Mass number; Nucleus 6. Neutrons; Atomic number; Mass number 7. Lithium: Li, 3; Bromine: Br, 35; Iron: Fe, 26; C…
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why does each element have a unique emission spectrum? varying electron…
Unique spacing of energy levels
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1. name the three particles of the atom and their respective charges ar…
1. a. Proton, Positive charge b. Neutron, No charge c. Electron, Negative charge 2. Atomic number, Chemical properties
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part c: types of reactions (5 marks) | chemical equation | type of reac…
1. Single - replacement reaction 2. Decomposition reaction 3. Double - replacement reaction 4. Combination (synthesis) reaction
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20.) the ph scale is used to measure how acidic or basic a substance is…
20a.) $0.2$ 20b.) $0.0631$
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explain your understanding by showing your work in writing the formulas…
Sodium nitride has the formula $Na_3N$ and is composed of sodium and nitride ions. Sodium nitrate has the formula $NaNO_3$ and is composed of sodium and nitrate ions.
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2. calculate the atomic mass of boron using the isotopes listed below. …
= 10.82amu
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extra credit: the horizontal rows of the periodic table of elements are…
B. Periods
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professor flores has been teaching introduction to chemistry for three …
C. automatic
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by changing the number of protons in an element you can change the? ¿al…
name of the element
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ions are atoms with a charge. one charge is positive, one is negative. …
B. Cation, D. Anion
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which element has the largest atomic radius in each pair? 1. lithium or…
1. Potassium 2. Phosphorus 3. Calcium 4. Carbon
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2025 chemistry unit test shaughnessy part a: multiple choice choose the…
(e) 2.
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the passage below describes an experiment. in each of three bowls, tom …
Does water mixed with salt evaporate faster than water mixed with sugar?
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the passage below describes an experiment. lemon juice can cause milk t…
Does the type of milk affect the size of clumps formed when the milk curdles?
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worksheet 2 1. (multiple choice) which of the following is not part of …
# Breve Explicación: 1. Los peligros Focus Four son las caídas, ser atrapado - en / entre, la electrocución y las lesiones por impactos con objetos. El fuego no es parte de ellos.…
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part b. instructions: for each of the following changes, identify it as…
1. Physical change 2. Chemical change 3. Physical change 4. Physical change 5. Physical change 6. Chemical change 7. Chemical change 8. Chemical change 9. Chemical change 10. Phys…
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#7 chemistry a schoology 2025 12. explain what ionization energy is mea…
Ionization energy is the energy needed to remove an electron from a gaseous species. The pattern is an increase across a period and a decrease down a group. Arrows on the periodic…
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the passage below describes an experiment. franklin remembered hearing …
Does the temperature of a soda affect how much carbonation it loses over time?
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b. play around, and write down three examples of atoms that have a stab…
| Number of particles in your nucleus: | Take a Screenshot of your atom | What element is it? | | ---- | ---- | ---- | | Protons: 1<br>Neutrons: 0 | (Screenshot not provided here,…
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i dont understand the periodic table of elements. can you explain why t…
Elements on the left side of the periodic table have low ionization energy and few valence - electrons, so they give away electrons. Elements on the right side have high electrone…