化学
化学反应、化学计量、分子结构与元素性质。
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where is the best place to find detailed information about a hazardous …
B. On the safety data sheet (SDS)
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which statement best describes the purpose of your organizations hazard…
To provide important safety information about hazardous chemicals to workers
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based on periodic trends, rank the elements in order of increasing elec…
Li < H < C < N
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common personal protective equipment (ppe) used to protect against expo…
B. Latex or nitrile gloves, C. Splash - resistant disposable gowns, D. Safety glasses or goggles
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what information is contained on a safety data sheet (sds)? (select all…
PPE to wear when using the chemical, Instructions for cleaning up an accidental spill or leak of the chemical, First aid measures to take if you are exposed to the chemical
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according to the occupational safety & health administration (osha), wh…
A. Whenever new hazardous chemicals are introduced in your work area D. During orientation to your work area
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(a) which is the limiting reactant when 0.300 mol co and 0.400 mol fe₃o…
$CO$ is the limiting reactant.
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how does osha define a hazardous chemical? select the correct answer an…
A. A chemical that is classified as a physical or health hazard
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what metalloid has commonly been used as an insecticide due to its effe…
# Breve explicación: El arsénico es un metalloide que históricamente se ha usado ampliamente como insecticida y como veneno debido a su efectividad. Las otras opciones, el boro, e…
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what is the purpose of a safety data sheet (sds)? select the correct an…
To provide important safety information about a hazardous chemical
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name ______________________ sept 19 be prepared for a quiz on friday (s…
4, 1, 3, 4
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what information should your organizations hazard communication program…
How to identify hazardous chemicals in your work area
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select the correct answer then click submit. where should you obtain in…
A. Safety Data Sheet (SDS)
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which example of medication administration is considered chemical restr…
B. Medications that are not a standard part of the patient's treatment that are given to control behavior
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question 1 of 9 carbohydrates are organic compounds that primarily serv…
B. Carbon, hydrogen, and oxygen.
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26. garter snake the garter snake is a common species in north america.…
\(|x - 88|\leq42\)
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read the lines from act ii, scene ii of romeo and juliet. juliet: o rom…
hopefulness and longing.
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multiple choice 1 point hydrogen bonds between water molecules are caus…
A. Polarity
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name olivia bettis date 8/15/25 class welding 5th instructor instructor…
1. fused 2. B 3. D. All of the above 4. cold welding 5. tensile strength 6. Resistance spot welding passes an electric current through the metal pieces at the contact point. The r…
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answer each question about the following atom when it becomes an ion. s…
1. Sulfide 2. $S$, $2 - $ 3. $2 - $, gains, 2
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phosphorus determine the ionic name. ion write the chemical symbol and …
Ion name: Phosphide Chemical symbol and charge: $P^{3 - }$ The ionic charge of 3 - is achieved when the atom gains 3 electrons.
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magnesium determine the ionic name. write the chemical symbol and charg…
1. Magnesium 2. Mg, 2+ 3. +2, loses, 2
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which compares the gases most commonly released by fertilizers and gase…
Chemicals from fertilizers can release nitrous oxide, while landfills release methane.
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fluorine determine the ionic name. fluoride ion write the chemical symb…
1. Chemical symbol and charge: F, - 1 2. The ionic charge of - 1 is achieved when the atom gains 1 electron.
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like mercury and lead. atmosphere high levels of methane gas detected. …
They will deny the company's drilling permit. Fracking reduces the soil, air, and water quality of an area.
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an oil and gas company plan to expand its fracking area. the company re…
deny
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nitrogen determine the ionic name. write the chemical symbol and charge…
1. Ionic name: Nitride ion 2. Chemical symbol and charge: $N^{3 - }$ 3. The ionic charge of $N^{3 - }$ is achieved when the atom gains 3 electrons.
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this is according to the ancient chaldean doctrine of two creations of …
C. malign
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you might have never seen the structure of this molecule before, but yo…
d) Freshly squeezed orange juice
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so if you only know the chemical formula of a sugar, you cannot tell wh…
B. Arrangement of functional groups
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answer each question about the following atom when it becomes an ion. b…
1. Ionic name: Beryllium ion 2. Chemical symbol and charge: $Be^{2 + }$ 3. The ionic charge of +2 is achieved when the atom loses 2 electrons.
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answer each question about the following atom when it becomes an ion. i…
- Ionic name: Iodide - Chemical symbol and charge: $I^-$, - 1 - The ionic charge of - 1 is achieved when the atom gains 1 electron.
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what is the chemical formula of fructose? have a look at the molecular …
A. $C_{6}H_{12}O_{6}$
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when dissolved in water, most glucose molecules form into 6 - membered …
B. Oxygen atoms
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what is the difference between a mixture and a compound? a mixture must…
B. A compound can only be separated into its components by chemical means.
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part 2b 10 marks choose 5 of 6 (lesson 2a) write the atomic notation fo…
a) $\ce{_{93}^{237}Np}$ b) $\ce{_{95}^{241}Am^{1 -}}$ c) $\ce{_{110}^{281}Ds}$ d) $\ce{_{118}^{292}Og^{3 -}}$ e) $\ce{_{69}^{169}Tm}$ f) $\ce{_{107}^{269}Bh^{3 -}}$
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beaker a beakers a & c beaker b beaker c which of the beakers above con…
D. Beaker C
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25. a chemical property of silver wire would be its _____. reactivity w…
reactivity with chlorine
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24. a sheet of paper is torn into several small pieces. which type of c…
Physical change only
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23. you are doing an evaporation experiment of an unknown liquid. when …
A. A mixture because you separated it physically and it is a solution.
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a sample of an unknown pure substance x is analyzed and found to contai…
| substance | mass of $E_1$ | mass of $E_2$ | pure substance? | |--|--|--|--| | A | 13.8 g | 5.24 g | mixture | | B | 18.1 g | 23.9 g | mixture | | C | 26.4 g | 7.55 g | mixture |
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22. which of the following is evidence that a chemical change has taken…
B. All of the above
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21. what is the correct method to separate salt from sand? dissolve the…
dissolve the salt in water - filter off the sand - evaporate the water
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20. melting, evaporating and sublimation ______ heat. nothing happens r…
require
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18. three ice - cubes are mixed into a glass of water. classify the mix…
A. A heterogeneous mixture of a solid and a liquid
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18. which of following is a compound? k ch₄ h₂ o₂
CH₄
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17. which of the following is a homogeneous mixture? chex mix orange ju…
C. a glass of salt water
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16. which of the following is heterogeneous, has the tyndall effect, an…
B. colloid
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1. which of the following is a physical property of a substance in the …
D. definite volume
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14 which of the following is an example of a homogeneous mixture? pure …
Pure air
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13. which of the following is a chemical reaction involving grass? a co…
A patch of grass turning yellow due to lack of sunlight.
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12. how can you distinguish a pure substance from a mixture? a pure sub…
A pure substance has a fixed composition; a mixture has a composition that may vary.
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11. which of the following shows a physical change?
D. (assuming the blue object is ice and represents melting which is a physical change)
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10. calcium hydroxide ca(oh)₂ meets the definition of which of the foll…
O compound
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which picture is the best example of an element?
B. Picture B
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pregunta de opción múltiple ¿por qué no hay fósforo en la atmósfera? el…
Ninguna de las opciones es correcta. El fósforo es un sólido en condiciones normales y reacciona fácilmente con oxígeno y otros elementos, por lo que no se encuentra libre en la a…
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select the correct answer to the question below. which of the following…
A. A person using a pipette to transfer chemicals
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which is the main difference between physical changes and chemical chan…
B. A chemical change forms one or more new substances but a physical change does not.
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an incomplete lewis structure is shown below. the structure only shows …
The oxygen atom will have a positive charge, 3 bonds (C - O, O - H) and 2 lone pairs. The left - hand carbon has 4 single bonds (3 to H and 1 to C), the right - hand carbon has 4 …
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22. you are allowed to enter the chemical preparation/storage area any …
22. B. False 23. B. False 24. A. True
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4. which of the following is a chemical property for sodium (na)? densi…
D. reacts with water
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18. never remove chemicals or other equipment from the laboratory * tru…
18. True 19. False 20. True 21. True
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isotope practice problems element with same # protons, and # of neutron…
- Atom with 15 protons and 17 neutrons: Number of electrons: 15, Atomic number: 15 - Zinc - 64: Number of protons: 27, Number of neutrons: 37 - Zinc - 66: Number of protons: 27, N…
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isotopes - notes and practice introduction how are the hydrogen atoms t…
1. $\frac{37}{17}\text{Cl}$ 2. Isotope notation: $\frac{35}{17}\text{Cl}$, Protons: 17, Neutrons: 18, Electrons: 17 3. Isotope notation: $\frac{14}{6}\text{C}$, Protons: 6, Neutro…
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14. eating hot cheetos is allowed in the lab * true false 15. hot glass…
14. B. False 15. A. True 16. A. True 17. B. False
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11. horseplay or practical jokes in the laboratory are * always against…
11. always against the rules 12. the science instructor 13. wash hands thoroughly with soap and water
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7. personal eyeglasses provide as much protection as * face shield safe…
7. none of the above 8. tied back or kept entirely out of the way with an elastic band, clips, or other confining device
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question 3 what determines a minerals unique characteristics? chemical …
Chemical composition and crystal structure
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3. after completing an experiment, all chemical wastes should be * left…
3. B. disposed of according to your instructor's directions 4. A. discuss the issue with your instructor
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how can the ratio of different elements affect matter? a it affects the…
C. It affects the physical and chemical properties of matter.
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what is formed when two or more atoms link up? a element b molecule c p…
B. molecule
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a molecule of water contains one atom of hydrogen and two atoms of oxyg…
FALSE
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a nucleus contains protons and electrons. true false
FALSE
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choose the correct answer. which atmospheric gas is being described? a …
D. argon
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an atom that loses or gains electrons to become either negatively or po…
ion
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the nucleus of an atom contains protons and what other particle? enter …
neutrons
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which of the following make up the nucleus of an atom? select all that …
A. neutron C. proton
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unit 3 comprehensive quiz l how many moles are in 54.3 grams of na? o 5…
2.36 moles
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what conversion factor should be used to convert 2.48 moles of ca to gr…
$2.48\text{ moles Ca}\times\frac{40.078\text{ grams Ca}}{1\text{ mole Ca}}$ (The third - option you provided has an incorrect value in the numerator, and the correct one is not am…
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match the following particle diagrams to their correct terms. element c…
First diagram: mixture Second diagram: compound Third diagram: element
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which of the following best describes isotopes of an element? atoms wit…
Atoms with the same number of protons but different numbers of neutrons
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how many moles are in 5.2 x 10^{23} atoms of barium? 0.864 mol 3.1 x 10…
0.864 mol
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why is radioactive dating important when approximating the age of earth…
Scientists can determine the order of when rocks formed on Earth.
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which of the following quantities is best represented by a mole? the nu…
The number of particles of water in a lake
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unit 3 comprehensive quiz e possible points 5 which element has a molar…
D. Al
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the english chemist john dalton formulated an atomic theory based on hi…
1. All elements are made up of tiny indivisible particles called atoms.
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unit 3 comprehensive quiz l possible points: 5 which statement correctl…
Protons and neutrons have nearly the same mass, while electrons are much lighter.
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unit 3 comprehensive quiz e possible points 5 a sample composed only of…
C. an element
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identify whether longhand notation or noble - gas notation was used in …
Potassium (K): longhand notation Iron (Fe): noble - gas notation Argon (Ar): noble - gas notation
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unit 3 comprehensive quiz l where in the atom are protons located? nucl…
A. nucleus
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4. which of the following describes the difference between weathering a…
4. weathering is the breaking down of rocks while erosion is the movement of the rocks by wind, ice, or water from one place to another 5. the sand component of soil
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match each atomic model to its description. possible points: 5 daltons …
- Dalton's Model (first atomic model): Atoms of any one element are identical to each other but different from atoms of other elements. Atoms combine in different whole number rat…
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which energy level (orbit) has electrons with least amount of energy? p…
The innermost orbit
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review questions: 1. why is the water molecule so important to organism…
1. Water is a universal solvent, participates in biochemical reactions, helps in temperature - regulation, and provides turgor pressure in plants. 2. Hydrogen ions ($H^+$) and hyd…
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the complete lewis electron - dot diagram for hconh₂ is shown above. id…
B. $sp^{2}$ hybridized and $120^{\circ}$
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in the reaction represented above, which of the following sets correctl…
B. $sp^{2}$, $sp^{3}$
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18. __________________ fluids are acid in the body and must be ________…
18. Some; neutralized; bases 19. bitter; slippery 20. The reaction between an acid and a base. 21. Salt and water. 22. neutral (around 7); homeostasis
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13 mark for review contains 1 sigma (σ) and 2 pi (π) bonds a b2 b n2 c …
B. $N_2$
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12 mark for review resonance is most commonly used to describe the bond…
B. $O_3$
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11 mark for review which of the following molecules has an angular (ben…
B. $O_3$