Chimie
Réactions chimiques, stœchiométrie, structures moléculaires et propriétés.
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which of the situations below describes an ethical dilemma related to f…
B. One pesticide is used to protect a crop from being destroyed, but studies have linked it to thyroid disorders.
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which of these is an example of food engineering? a. buying organically…
C. Using glass containers to reheat food
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which of the following is the correct formula for cesium sulfide? a. cs…
C. $Cs_2S$
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which of the following is used to indicate the number of each type of a…
A. A prefix
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which of the following is the correct formula for nitrogen trifluoride?…
C. NF₃
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what is the oxidation number of an element? a. the group number for the…
C. The charge an element would have if it lost or gained electrons
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what is the oxidation state of cobalt(iii)? a. +2 b. -3 c. +3 d. +5
C. +3
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which of the following is the correct name for bacl₂? a. monobarium dic…
D. Barium chloride
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how are transition metals named in metal compounds? a. a roman numeral …
A. A roman numeral in parentheses follows the name of the metal.
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which of the following is the correct name for ccl₄? a. carbon chloride…
B. Carbon tetrachloride
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how are ionic compounds named? a. a number is given in parentheses afte…
B. The name of the first element is followed by that of the second element, the latter of which ends in -ide.
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7. describe what is going on with the molecules during the different ph…
| Water vapor | Ice | Water | |--|--|--| | Molecules are far apart, move freely with high kinetic energy. | Molecules are arranged in a fixed, regular lattice, vibrate in place wi…
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7 describe what is going on with the molecules during the different pha…
60000 ppt
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3. use models suppose a black ball represents a hydrogen atom and a yel…
Use 1 yellow ball (nitrogen atom) and 3 black balls (hydrogen atoms), and connect the 3 black balls to the 1 yellow ball.
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5. describe ionic bonding and what happens between na and cl when they …
5. Ionic bonding is electron - transfer. Na donates an electron to Cl, Na becomes $Na^+$ as it loses an electron and Cl becomes $Cl^-$ as it gains an electron, and they bond due t…
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48) most antidepressants work by increasing the levels of which of the …
D. All of the above
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modeling atoms and molecules how can you make models of simple molecule…
1. The four kinds of atoms were represented by colored - marked foam balls. Toothpicks represent a chemical bond. 2. 3
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draw three molecules of water with hydrogen bonding (make sure to use t…
The following is a simple sketch to represent three water molecules with hydrogen bonding: H - O - H ··· H - O - H ··· H - O - H (In a more proper Lewis - structure style, the oxy…
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select the correct answer. carlos is interested in pursuing a career th…
D. Agricultural science in the agriculture, food, and natural resources cluster
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the table below describes four atoms. atom a atom b atom c atom d numbe…
A. Atom A and Atom D B. Atom B and Atom C
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aqueous potassium nitrate and solid silver bromide are formed by the re…
$KBr(aq)+AgNO_3(aq) ightarrow KNO_3(aq) + AgBr(s)$
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this is the chemical formula for methyl tert - butyl ether (the clean -…
3.09 mol
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rank the following newman projections in order of decreasing energy, fr…
A > B > C > D
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rank the following newman projections in order of decreasing energy, fr…
A > B > C > D
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question 3 of 29 (1 point) | question attempt: 1 of 5 the measured dipo…
C. It exists entirely in the anti - conformation.
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this is the chemical formula for nickel tetracarbonyl (a powerfully poi…
32.8 mol
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the chemical formula for zinc nitrate is: zn(no3)2. calculate the molar…
189.4 g/mol
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silicon, which makes up about 25% of earths crust by mass, is used wide…
28.0855 amu
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cao calcium oxide k2o potassium oxide n2o dinitrogen oxide mgo magnesiu…
d. 4 ### 19.
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a chemist determined by measurements that 0.0150 moles of silver partic…
$1.62\ g$
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a penny has a mass of 2.50 g and the moon has a mass of 7.35×10²² kg. u…
$4.88\times 10^{1}$
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3. which answer most accurately defines a buffer system in chemistry? a…
A. A system that resists changes in pH when an acid or base is added
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choose the correct answer. how does chemical weathering occur? plants, …
by chemically breaking down rocks by water and gases
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choose the correct answer. which of these describes physical weathering…
rocks being broken down by freezing and thawing
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tree roots can break down rock into soil. which type of weathering is t…
B. Physical
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a robot spacecraft returned samples from the planetesimal 98765 aleks, …
97.96 amu
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question 25 please match the key word to the correct definition. column…
1. a 2. g 3. c 4. f 5. b 6. d 7. e
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question 14 the amount of energy needed for a reaction to occur is call…
d. activation energy
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a chemical test is used to measure reaction time blood alcohol content.…
Blood alcohol content.
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written response use the following information to answer the next two q…
1. $22.50$ g 2. $\%$ yield: $90.22\%$, $\%$ error: $9.78\%$
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consider the molecules (a - e) drawn below: which structure(s) is/are a…
A. structure A B. structure B C. structure D D. structure E
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chemistry 20 stoichiometry quiz name: ebtesam numeric response use the …
$3.03$
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chemistry 20 stoichiometry quiz name: ebtesari numeric response numeric…
17.3
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use the following information to answer the next question. __ca(oh)₂(aq…
1.10
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chemistry 20 stoichiometry quiz name: ebtesam multiple choice 7. how ma…
481 (corresponding to the third option in the multiple - choice list)
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use the following information to answer the next question. when reacted…
2.71
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5. a correct assumption that is made when using stoichiometry for a the…
the reaction goes to completion; the reactions are spontaneous
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chemistry 20 stoichiometry quiz name: ebtesam multiple choice 4. nabr(a…
B. \(CuBr_2(s)+Na_3PO_4(aq)\)
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chemistry 20 stoichiometry quiz name: ebtesam multiple choice 3. what i…
342.17 g/mol
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2. in a lab, a technician measures out 2.05 g of a compound which was f…
2.85 g/mol
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chemistry 20 stoichiometry quiz name: edesam multiple choice 1. how man…
0.461
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application questions: answer the following questions. show all work fo…
420 nm
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write down the oxidation state of each of the labeled atoms in this mol…
| atom | oxidation state | | ---- | ---- | | a | - 2 | | b | - 2 | | c | - 2 | | d | 0 | | e | - 2 |
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which of the following is insoluble in water? select all that apply. sm…
Small non - polar gases, Hydrophobic proteins
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question 2 of 5 when working with damaged or chemically treated hair, r…
True
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question 1 of 2 6 points fill in the blanks: hair spray, also known as …
1. spritz 2. serum 3. styling cream 4. styling lotion 5. gel 6. edge control
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8. write the balanced equation for the decomposition reaction of solid …
a. $6.00\ g$ b. $95.83\%$
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practice: 7. answer the following questions about this reaction: 2na(s)…
a. The limiting reactant is $Na$. b. The mass of the excess reactant ($H_2O$) left over is approximately $6.00$ g. c. The mass of $NaOH$ formed is $13.8$ g and the mass of $H_2$ f…
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write the systematic name of each organic molecule: structure name
2,5 - dimethylheptane 5 - ethyl - 3 - methyloctane 4 - methylhexane
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name the following organic compounds:
2,3,6 - trimethylheptane 2 - ethyl - 2,2 - dimethylhexane
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practice it what substances are blocked by the blood - brain barrier? o…
B. Antibodies and other immune system molecules; C. Harmful substances like bacteria, viruses, and toxins
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practice it what are neurotransmitters? proteins that transport oxygen …
D. Chemical messengers that bind to receptors on the next neuron, transmitting the signal across the synapse.
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1. why should an iron almirah be called solid? three marks questions : …
An iron almirah is called solid because it has a definite shape and volume, and its particles are closely - packed with strong intermolecular forces. ### 2. A truck starts from re…
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4. how does cork act as a protective tissue ? 5. to make a saturated so…
The concentration of the saturated solution of sodium chloride at 293 K is approximately 23.08%
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section - a tick the correct option : 1. which of the following is a tr…
- Tick the correct option: - 1. b) Sugar in Water - 2. None of the given options - 3. a) 3 - 4. a) C - 5. a) 100 N - Fill in the Blanks: - 1. cooling - 2. Tendons - 3. involuntary…
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list each substituent on the main chain of this organic molecule on a s…
| name | location | | ---- | ---- | | methyl | 3 | | methyl | 4 |
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ecdysone is a steroid hormone in insects that is involved in larval mol…
Carbon highlighted in red: Tertiary carbon Carbon highlighted in blue: Secondary carbon
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determine if the organic reactant is oxidized or reduced in the reactio…
The organic reactant is oxidized.
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rank the following compounds according to their heat of combustion. com…
2 - methylheptane: 2 2 - methylhexane: 1 Nonane: 4 Octane: 3
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rank the following compounds according to their heat of combustion. com…
Nonane > Octane > 2 - methylheptane > 2 - methylhexane
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match the boiling points with the appropriate alkanes from the list bel…
50 °C: 2,2 - dimethylbutane 60 °C: 2 - methylpentane 69 °C: hexane 98 °C: heptane
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provide the iupac name for the following compounds. part 1 of 3 ch₃(ch₂…
Part 1: pentatetracontane Part 2: 3,6 - diethyloctane Part 3: 4,8 - dimethylundecane
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provide an acceptable iupac name for the following branched alkane.
2,2,5 - trimethyloctane
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consider the branched alkane below and complete the following tasks bas…
$C_6H_{14}$
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part 2 of 2 what is the molecular formula for 2,6,10 - trimethyltrideca…
$C_{16}H_{38}$
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what type of orbital does the overlap of the two p orbitals shown below…
$\pi$
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part 2 of 2 what are the ccc bond angles? enter a value without units b…
∠abc = 120 ∠bcd = 120 ∠cde = 120
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using the highlight tool, assign the hybridization of each carbon as fo…
For the double - bonded carbons in the structure, use the green highlighter ( $sp^{2}$ hybridization). For the single - bonded carbons in the structure, use the blue highlighter (…
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consider the alkane with molecular formula c₃h₈. part: 0 / 2 part 1 of …
$CH_3CH_2CH_3$
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consider the molecular formula c₄h₁₀. part 1 of 2 write the condensed f…
A straight - chain zig - zag structure with 3 lines (representing C - C bonds) and no atoms labeled (since carbon atoms are at the ends and intersections and hydrogen atoms are as…
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consider the molecular formula c₄h₁₀. part 1 of 2 write the condensed f…
$CH_3CH_2CH_2CH_3$
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which of the hydrocarbons below are related as isomers of each other? c…
compound A, compound C
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question 3 of 32 (1 point) | question attempt: 1 of 5 part 3 of 3 the o…
Hybridization: $sp^{3}$ Molecular geometry: bent
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provide the hybridization and molecular geometry for the indicated atom…
Part 1: Hybridization: $sp^2$ Molecular geometry: trigonal planar Part 2: Hybridization: $sp^3$ Molecular geometry: trigonal pyramidal
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ch 2 question 2 of 32 (1 point) | question attempt: 1 of 5 part 1 of 4 …
C2 $sp^{3}$ - C3 $sp^{2}$
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what orbitals are used to form each indicated bond in the molecule show…
C3 $p$ - C4 $p$
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what orbitals are used to form each indicated bond in the molecule show…
$sp^{2}-sp^{2}$
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provide the molecular formula for each of the following compounds. part…
Part 1: $C_{7}H_{14}$ Part 2: $C_{6}H_{12}$
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5.46 aluminium chloride, alcl₃(s), is made by reacting scrap aluminium …
(a) Chlorine ($Cl_2$) is the limiting reactant. (b) The maximum mass of $AlCl_3$ is approximately $5.08\ g$. (c) The mass of the excess reactant ($Al$) remaining is approximately …
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16. a sample of n₂o₄(g) is placed in an empty cylinder at room temperat…
$K_p = 0.158$, $P_{N_2O_4}=0.674$ atm, $P_{NO_2}=0.326$ atm
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15. at 500 k, a 10.0 l equilibrium mixture contains 0.424 mol n₂, 1.272…
$0.38\ mol$
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14. explain how each of the following affects the amount of h₂ present …
a. The amount of $H_2$ decreases. b. The amount of $H_2$ increases. c. The amount of $H_2$ remains unchanged. d. The amount of $H_2$ remains unchanged. e. The amount of $H_2$ rema…
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13. consider the following reaction: mathrm{hconh}_{2}(mathrm{g})=mathr…
$5.62\ atm$
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12. equilibrium is established in a 2.50 l flask at 250 °c for the foll…
$[PCl_5]=0.191\ M$, $[PCl_3]=0.249\ M$, $[Cl_2]=0.0291\ M$
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what is the difference in energy (in joules) between the n = 5 and n = …
$4.90\times 10^{-20}$ ### Question 2
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11. lead metal is added to 0.100 m cr³⁺(aq). what are pb²⁺, cr²⁺, and c…
$[Pb^{2 + }]=0.050$ M, $[Cr^{2 + }]=0.100$ M, $[Cr^{3 + }]\approx0$ M
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question 14 organic chemistry is a science based on the study of: funct…
carbon compounds
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which molecule contains a carboxyl group and acts as an acid? od oa oc …
D.
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which molecule contains a carboxyl group and acts as an acid? a. molecu…
D. The molecule with -COOH group (It seems there was an error in the original answer choice selection in the question setup as the correct answer should be D if we are looking for…
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question 12 hydrocarbon molecules attract water are polar contain only …
C. contain only hydrogen and carbon atoms.