Chimie
Réactions chimiques, stœchiométrie, structures moléculaires et propriétés.
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2h₂ + o₂ → 2h₂o synthesis decomposition single displacement double disp…
A. Synthesis
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select the true statements. sucrose and lactose have different chemical…
All the statements are true.
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why are the alkaline earth metals less reactive than the alkali metals?
Alkaline earth metals are less reactive than alkali metals because they have higher ionization energies (harder to lose electrons as they have two valence electrons to lose compar…
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multiple choice 1 point which pair forms an ionic compound? two metals …
A metal and a nonmetal.
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ionic compounds are made when metals join with nonmetals. me the name o…
The ending is changed to “-ide”
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which list includes only physical properties? density, reactivity, and …
Boiling point, conductivity, and color (the second option).
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25 multiple choice 1 point a snowball thrown at an ice cream truck at v…
thermal energy
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which is an intensive property of a substance? o density o volume o len…
density
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a geochemist examines a piece of metal that he found in the soil. he pe…
He is identifying the metal using physical properties only.
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which statement describes a physical property of copper? it reacts with…
It can be reshaped by a force.
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which of these is an example of investigating an intensive property? we…
C. determining if a rock is magnetic
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a student performs the following experiment. step 1: she pours a colorl…
a chemical change in step 1 and a physical change in step 2
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the table below shows the freezing points of four substances. substance…
butane
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which of these is an example of a physical change? sugar dissolving in …
sugar dissolving in warm water
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question 7 (03.03 mc) benzene and pcbs were among many toxins that were…
True
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explain why phospholipids dropped in water form a micelle. complete the…
The phospholipid **tails** face away from the water because they are **hydrophobic**. The phospholipid **heads** face toward the water because they are **hydrophilic**.
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read these instructions carefully. to ensure full credit, show all corr…
\(2Fe^{2 + }(aq)+Cu^{2 + }(aq)\to 2Fe^{3 + }(aq)+Cu(s)\)
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a molecule contains 24.36 g n and 62.64 g ag. what is its empirical for…
\(AgN_{3}\)
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what is the empirical formula for a compound containing 37.5% carbon, 1…
$CH_{4}O$
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exam 3 fall 2025 your initials nt (vi) (10 points) the following (figur…
VI. a VII. Gas particles engage in elastic collisions between each other and the walls of the container (similar to billiard balls)
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a compound is analyzed as 17.6% na, 39.7% cr, and 42.7% o. what is the …
\(Na_{2}Cr_{2}O_{7}\)
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a compound sample contains 53.7 g fe and 46.3 g s. what is the empirica…
$Fe_2S_3$
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a compound is analyzed as 33.9% ge and 66.1% cl. what is the empirical …
\(GeCl_{4}\)
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multiplying each value by two gives the ratio below. what is the empiri…
\(C_{5}H_{8}O_{2}\)
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2.49375 c : 3.9901 h : 1.000 o the ratio does not give whole numbers, s…
\(2\)
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d. everything around us is made up of different elements. the air has o…
- A. A neutral atom has an equal number of protons and electrons. - B. A + ion has more protons than electrons. - C. A - ion has more electrons than protons.
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there are 4.9875 mol c, 7.9802 mol h, and 2.00 mol o in the sample. div…
\(2.49375\) \(C:3.9901\) \(H:1\) \(O\)
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lucite contains 59.9 g c, 8.06 g h, and 32.0 g o. you want to determine…
\(2.00\space mol\)
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using your periodic table, choose the element whose neutral atoms have …
Mg
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lucite contains 59.9 g c, 8.06 g h, and 32.0 g o. you want to determine…
\(7.996032\)
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given only the information from the periodic table entry shown below an…
It has 14 protons, It has 14 electrons.
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lucite contains 59.9 g c, 8.06 g h, and 32.0 g o. you want to determine…
\(4.9875\)
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using your periodic table, give the number of electrons present in a ne…
56
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the ratio is 1 c: 2 s. what is the empirical formula of the compound? 1…
2) \(CS_{2}\)
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1 multiple choice 1. select the best answer. (1) (5 points) heat is bes…
(I) energy transferred as the result of a temperature difference. (II) an endothermic process. (III) \(20\space kJ\) (IV) \(0.104\space L\) (V) \(26.2\space mL\)
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changing the number of protons in an atom will change which of the foll…
The atom's mass, The identity of the element, The charge of the atom
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check each particle that is used to form bonds. protons neutrons electr…
electrons
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there are 0.657785 mol c and 1.31275 mol s in the sample. what is the w…
1 (for \(C\)) and 2 (for \(S\))
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check each particle that is used to form bonds. protons neutrons electr…
electrons
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why does the na+ ion have a +1 charge? it has gained an extra proton. i…
It has lost an electron.
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a sample contains 7.90 g c and 42.1 g s. you want to determine the empi…
\(1.313\space mol\) (calculated as \(\frac{42.1}{32.065}\approx1.313\))
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2. sketch in the \stairstep\ line that separates the metals from the no…
a. Alkali metal b. Radioactive metal (actinide) c. Noble gas d. Transition metal e. Post - transition metal f. Alkaline earth metal g. Post - transition metal h. Transition metal …
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why does the na+ ion have a +1 charge? it has gained an extra proton. i…
It has lost an electron.
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a sample contains 7.90 g c and 42.1 g s. you want to determine the empi…
\(0.657785\)
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the ratio is very close to 1 c to 2 h. what is the empirical formula? c…
\(CH_2\)
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there are 7.16 mol c and 13.9 mol h in the sample. divide by smallest: …
$1C:2H$
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there are 7.16 mol c and 13.9 mol h in the sample. divide by smallest: …
carbon
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the sample has 86 g c and 14 g h. mass to mole: how many moles of h are…
13.9 mol
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the sample has 86.0 g c and 14.0 g h. mass to mole: how many moles of c…
7.16 mol
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polyethylene is 86.0% c and 14.0% h. determine the empirical formula of…
86.0 g C and 14.0 g H
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what radioactive element has the lowest atomic number? how many of the …
- The radioactive element with the lowest atomic number is technetium (Tc). - There are 38 radioactive elements.
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how many elements are gaseous at room temperature? where do the gaseous…
- There are 11 elements (He, Ne, Ar, Kr, Xe, Rn, H₂, N₂, O₂, F₂, Cl₂) that are gaseous at room temperature. - Gaseous elements tend to be located on the right - hand side of the p…
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question 18 of 20 the subscript in a chemical formula represents the nu…
A. molecules of reactants, D. 24
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question 17 of 20 what type of reaction is this? (5 points) extra conte…
D. double replacement
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question 16 of 20 what is a large number written before a compound in a…
A. coefficient
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which of the following sets of coefficients will balance the reaction b…
B. \(1/2\), \(1\), \(1/2\), \(1\)
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question 13 of 20 what type of reaction is this? (5 points) extra conte…
B. decomposition
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a compound has the empirical formula given below. c₃h₄o₃ which compound…
\(C_6H_8O_6\)
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check each particle that is found in the nucleus. protons neutrons elec…
protons, neutrons
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what is the empirical formula of this compound? na₂s₂o₈ naso₄ na₂so₄ na…
\(NaSO_4\)
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a compound has the empirical formula given below. ch which compound rep…
\(C_6H_6\)
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what type of reaction is this? (5 points) ethan content ch4 + o2 → co2 …
E. combustion
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a compound has the empirical formula given below. no₂ which compound re…
\(N_2O_4\)
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what is the empirical formula for this compound? al₆o₉ al₃o₂ al₂o₃ al₆o₉
\(Al_2O_3\)
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question 10 of 20 what type of reaction is this? (5 points) extra conte…
D. double replacement
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question 9 of 20 which of the following sets of coefficients will balan…
A. \(2,2,1\)
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question 7 of 20 which of the following sets of coefficients will balan…
B. 2,3,2
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question 6 of 20 how many molecules of carbon dioxide are in following …
A. 6
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true=10 points false=5 points 1. mechanical energy requires movement 2.…
1. True 2. False 3. False 4. False 5. False 6. True 7. False 8. True 9. True 10. False 11. True 12. False 13. False 14. True 15. True
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question 4 of 20 what does the arrow in a chemical reaction represent? …
D. all of the above
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which of the following has a \\( \\delta h^{\\circ}_{f}=0 \\mathrm{~kj}…
## Question 1 C. \(N_2(g)\) ## Question 2 \(-90.5\) ## Question 3 \(52.4\)
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which phases change are occurring at point b? melting and freezing free…
Melting and freezing
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which phase change is occurring from point c to point e? a solid is cha…
A liquid is changing into a gas.
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based on the data presented, what can james conclude about how adding a…
Adding heat decreases the amount of time it takes molecules to spread thoroughly.
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a sample of h2so4 is found to contain 1.05 g of h, 16.67 g of s, and 33…
$65.25\%$
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select the answer that explains why the balloon in hot water inflates. …
When heat is added to the bottle, air molecules move faster and spread farther apart.
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a sample of ca(c₂h₃o₂)₂ is found to contain 40.08 g of ca, 48.04 g of c…
$25.34$
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a 50.00 g sample of an unknown compound is found to contain 17.97 g of …
\(35.94\%\)
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a 43.40 mg sample of an alcohol contains 15.10 mg of o, 22.60 mg of c, …
\(34.8\%\)
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exam 3 fall 2025 your initials nt 5. for the following mixtures/combina…
(I) \(2HCl(aq)+Ba(OH)_2(aq)=BaCl_2(aq)+2H_2O(l)\) (II) \(2C_4H_{10}(g)+13O_2(g)=8CO_2(g)+10H_2O(l)\) (III) \(NR\) (IV) \(3Zn^{2+}(aq)+2Al(s)=2Al^{3+}(aq)+3Zn(s)\) (6) \(5Fe^{2+}(a…
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a 43.40 mg sample of an alcohol contains 15.10 mg of o, 22.60 mg of c, …
\(52.1\%\)
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the molar mass of nh3 is 17.04 g/mol. what is the percent h in nh3? (h …
\(17.8\%\)
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the molar mass of nh3 is 17.04 g/mol. what is the percent n in nh3? (h …
\(82.22\%\)
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what is the molar mass of nh3? (h = 1.01 g/mol, n = 14.01 g/mol)
\(17.04\ g/mol\)
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name: tanahah grey date: 11/17/25 p:3 types of mixtures and methods for…
1. B. Boiling point 2. C. A solvent is used to dissolve the ink solutes so that as they wick up a strip of filter paper the pigments separate. 3. A. Beans in water 4. C. Distillat…
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18. when vinegar and baking soda are combined, bubbles begin to form. i…
C. show that a new gas is forming
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how many formula units (f.un.) are in 35.0 g kno₃? (1 mol kno₃ = 101.11…
Coefficient (green): \(2.08\) Exponent (yellow): \(23\)
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iclicker what is the buffer capacity of 0.8l of a 0.1m ch3coona / 0.1m …
D. \(0.06\ mol\)
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how many formula units (f.un.) are in 12.5 g nh4cl? (1 mol nh4cl = 53.5…
Coefficient (green): \(1.4\) Exponent (yellow): \(23\)
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8. which of the following is a characteristic of all chemical changes? …
D. a new material is formed
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what is the mass of 3.01×10²³ molecules of c₆h₁₂o₆? (1 mol c₆h₁₂o₆ = 18…
\(90.09\text{ g}\)
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13. according to the law of conservation of mass, * a. matter is always…
13. D. matter is not created or destroyed in a chemical reaction 7. D. baking the dough to form the crust
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what is the mass of 2.40 × 10²⁴ molecules of c₃h₈? (1 mole c₃h₈ = 44.11…
\(176\) g
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15. substances that start a chemical reaction are known as the * a. rea…
15. A. reactants 24. D. the formation of magnesium oxide
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a student is asked to organize colored pencils for a class project. the…
- First question: Hand - picking. - Second question: Filtration. Hot water passes through coffee grounds (solid) and filter, liquid coffee passes through, coffee grounds are retai…
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20. which activity is an example of a chemical change? * a. dissolving …
20. D. burning wood to produce ashes 5. A. physical
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14. crushing large stones into smaller stones is an example of a * a. p…
A. physical change
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22. the equation below shows the products formed when a solution of sil…
22. B. equal to the total mass of the product 19. B. equal to the mass of the carbon plus the oxygen
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23. the flask and its contents had a mass of 120 grams before the exper…
C. 120g
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how many molecules of methane, ch4, are in 125 g ch4? (1 mol ch4 = 16.0…
Coefficient (green): \(4.7\) Exponent (yellow): \(24\)