Chimie
Réactions chimiques, stœchiométrie, structures moléculaires et propriétés.
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which of the following solvents would be disposed in the halogenated so…
B. Dichloromethane
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imagine the two following scenarios: 1. you pour a small amount of non …
d) 2. is worse than 1.
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well done! how should you dispose of the remaining methanol solution? a…
B. Into organic solvent waste
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there is some remaining sodium hydroxide - methanol solution that we ha…
d) Explosive
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part 3 (1 point) predict which of the two orders is preferred. choose o…
HOCl is the preferred arrangement.
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why is it important to work in the fume hood during this step? a) metha…
a) Methanol gets very volatile at high temperature
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3. ¿cómo hacen las compañías de refrescos para mantener más dióxido de …
3. c) Aumentando la presión 4. Aumentar la temperatura 5. Disminuye 6. Falso (El refresco se embotella a baja temperatura para mantener el dióxido de carbono disuelto)
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tarea de ciencias de séptimo grado tema: cambio de solubilidad pasaje d…
# Explicación breve: 1. Según el texto, para la mayoría de los solutos sólidos, la solubilidad aumenta a medida que aumenta la temperatura del disolvente. 2. El texto menciona que…
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24/34 adding soap to water ... increases the cohesion and hydrogen bond…
C. decreases the surface tension of the water by breaking hydrogen bonds, so the water can clean the greasy dishes.
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small insects can walk across the surface of calm water. their feet pus…
The insects are light enough so that they do not break the hydrogen bonds creating cohesion that hold the water molecules together
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all of waters unique properties (cohesion, adhesion, universal solvent,…
water is polar with a partial positive end and a partial negative end that attract other molecules.
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which of the following hazards does not apply for methanol? a) flammabl…
c) Oxidizing
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how would you write the conversion reaction from oil to biodiesel? a) o…
B. oil + alcohol + catalyst → biodiesel + glycerol + catalyst
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42) the name of kno₃ is potassium nitratide. 43) the law of constant co…
44) C. N = 1, H = 7, C = 2, O = 2 45) A. molecular compound 46) B. MgS 47) D. 16
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the table shows the number of students in each grade at prairie middle …
1. 80 students in the 8th grade study chemistry. 2. There are 100 students in the 8th grade. 3. First, find $\frac{1}{5}$ of the number by dividing the number by 5. Then multiply …
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a student draws this lewis structure for the neutral covalent species s…
Sulfur and oxygen have nonzero formal charges.
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when will the central atom in a covalent structure typically have an ex…
Surrounding atoms are much smaller than the central atom. Nonzero formal charges on individual atoms can be reduced. Surrounding atoms, for example oxygen or a halogen, are highly…
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multiple choice. choose the one alternative that best completes the sta…
24) C 25) C 26) A 27) D 28) A 30) B
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a) provide the names for the following organic compounds: a) ch3c=chch=…
a) 6 - bromo - 2 - ethyl - 3,5 - octadiene b) 4 - fluoro - 2 - methyl - 1 - propylcyclopentene c) 5 - bromo - 6 - chloro - 2 - (phenyl) - 3,7 - decadiyne d) 2 - (tert - butyl) - 1…
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16) the standard si unit for temperature is: a) atmospheres. b) kelvin.…
16) B. Kelvin 17) B. 33.6 18) A. $1.75\times 10^{4}$ 19) A. 4.82 mL 20) A. $10^{-3}$ 21) T 22) F 23) T
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exam 1 chapters 1 - 5 please, turn off your cell phone and use only pen…
1. T 2. T 3. F 4. A 5. C 6. C 7. B
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48) choose the pair of names and formulas that do not match. a) calcium…
48) E. Potassium sulfate: $(NH_4)_2SO_4$ 49) B. iodic acid 50) B. $I_2S_5$
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40) what is the atomic mass of the hydrogen isotope that contains 2 neu…
40) C 41) T 42) F 43) T 44) C 45) A 46) B 47) D
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true/false. write t if the statement is true and f if the statement is …
31. F 32. T 33. T 34. C. an anion 35. D. K⁺ 36. E. none of the above 37. C. 2 - 38. D. 8 protons and 10 electrons 39. B. atoms of the same element that have different number of ne…
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multiple choice. choose the one alternative that best completes the sta…
24) C. A substance composed of two or more pure elements in fixed, definite proportions. 25) C. those that a substance displays without changing its composition. 26) E. none of th…
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16) the standard si unit for temperature is: a) atmosphere, b) kelvin, …
16) B. Kelvin 17) B. 33.6 18) A. $1.75\times 10^{4}$ 19) A. 4.82 mL 20) A. $10^{-3}$ 21) T 22) F 23) T
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8) a sample of wood with a mass of 3.0 grams was burned in an open dish…
8. B 9. E 10. C 11. T 12. T 13. F 14. E 15. B
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please, turn off your cell phone and use only pencil. write your name o…
1. T 2. F 3. F 4. A. The carbon dioxide is forced to mix with the water by the presence of sugars. 5. C. a model that explains the underlying reasons for observations and laws 6. …
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at what temperature does iron turn into a gas? what does this tell you …
Iron turns into a gas at 2862 °C (5182 °F or 3035 K). This high boiling - point indicates that the attraction between iron's particles (atoms) is strong due to the presence of str…
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oxygen and nitrogen are both gases at room temperature. explain why oxy…
Oxygen has a greater molar mass than nitrogen. The greater number of electrons in oxygen molecules leads to stronger London - dispersion forces between its particles compared to n…
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a student was randomly given compounds i and f from the group of compou…
Brady's test (2,4 - DNP)
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a student was given from the list of the compounds below a, b and d bli…
A = Brady, B = haloform
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multiple answer 10 points from the list of structures below, which of t…
F
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1. provide the structural formulas for the following organic compounds:…
a) $CH_3C(CH_3)=C(CH_3)CH_3$ b) A 5 - membered ring with a Br on one carbon and an I on an adjacent carbon c) A benzene ring with $-CH_2CH(CH_3)_2$ attached to one of its carbons …
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marina is heating a solution in her chemistry lab. the temperature of t…
C. (4, 32)
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provide the structural formulas for the following organic compounds: a)…
a) $CH_3C(CH_3)=C(CH_3)CH_3$ b) Cyclopentane ring with Br at C - 1 and I at C - 2.
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what causes the styrofoam to disappear into the acetone?
Styrofoam (polystyrene) is soluble in acetone, and acetone breaks down its structure causing it to dissolve.
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what causes the styrofoam to disappear into the acetone? your answer wh…
1. Acetone dissolves the polystyrene in Styrofoam. 2. Iron oxide or other magnetic particles.
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what is it called when something dissolves into something else? liquidi…
D. Solubility
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2.4 atomic lewis structures name: directions: answer the following ques…
Elements in Group 1 have 1 valence electron and their Lewis - dot diagrams have 1 dot. Elements in Group 18 have a full outer shell (2 for He and 8 for others) and their Lewis - d…
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6. what is the schematic symbol for the toggle switch?
B.
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2. which of the following is not a schematic symbol for a switch?
B. The wavy - line symbol (b) is not a schematic symbol for a switch.
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select the schematic symbol for a fuse.
The second symbol from the top (the wavy - line element between two straight lines)
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additional details were added for this assignment. 4. because bunsen bu…
Personal and other protective equipment: goggles, laboratory coat Physical hazards: burns from hot equipment, electrical, open, exposed flame Chemical Hazards: none Environmental …
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read the text. air pressure is the pressure in a given area caused by t…
Altitude is lower, such as at sea level. - Air pressure is higher. Altitude is higher, such as at the top of Mount Everest. - Air pressure is lower.
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give the complete common name, including aleks data resource.
Glucose
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select the schematic symbol for a rotary switch.
The first schematic symbol (with multiple circular contact points and a moving element between them)
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select the schematic symbol for a slide switch.
The second option (the symbol with a slanted line connecting two circular terminals and another terminal below).
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read the text. you have probably heard of the ph scale, which measures …
Hydronium ions form in the solution - The solution becomes more acidic. Hydroxide ions form in the solution - The solution becomes more basic.
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17. boron has two naturally occurring isotopes boron - 10 and boron - 1…
Boron - 11 is more abundant on Earth.
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recall that all isotopes of an element have the same physical and chemi…
The average atomic mass of oxygen is approximately $15.9992$ amu.
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question 5.4.1 select all special safety considerations present for thi…
Personal and other protective equipment: goggles, laboratory coat Physical hazards: burns from hot equipment, electrical, open, exposed flame
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name: passion rose date: 10/1/25 why is water so freaking cool? how muc…
1. Water is cool because of its unique physical and chemical properties such as high heat - capacity, hydrogen - bonding, and solvent capabilities. 2. Only a small fraction of the…
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select the correct name: 10. na₂s sodium sulfate (purple) sodium sulfid…
10. sodium sulfide (orange) 11. magnesium nitride (yellow) 12. aluminum chloride (purple) 13. iron (II) oxide (pink) 14. copper (II) bromide (magenta) 15. potassium phosphide (gre…
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question 5.3.6 use the five lighting the bunsen burner with a first lig…
a. safety lighter, Bunsen burner b. closed, yellow
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no additional details were added for this assignment. base - wide and h…
Air intake collar - 1, Air ports - 3, Gas intake - 2
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when naming an acid comprised of an anion such as perchlorate, the pref…
C. perchloric acid
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which of the following generally specifies the name of an oxyacid where…
1. <modified anion name>ous acid 2. <sulfur>, <phosphor>
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which of the following generally specifies the name of a binary acid su…
Question 1: Hydro<modified element name>ic acid Question 17: <modified anion name>ic acid
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question 5.2.3 there are two solutions, each containing cations of only…
First solution: Potassium cations Second solution: Strontium cations
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when naming binary molecular compounds, the name of the more__________ …
1. metallic, -ide 2. hydrogen ions
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question 12 1 pts the roman numeral in iron(ii) chloride specifies ____…
Question 12: the charge on the metal cation Question 13: True
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iron is a metal with variable ionic charges and can exist as either a _…
Question 1: D. 2+, 3+ Question 2: False
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most of the and some main group metals can form two or more cations wit…
1. D. transition metals 2. B. Roman numeral
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most of the____ and some main - group metals can form two or more catio…
1. D. transition metals 2. B. Roman numeral
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question 5.1.10 an element in an electrical discharge produced this bri…
Sr
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match the following everyday ionic compounds with their common uses. so…
sodium chloride: ordinary table salt sodium hypochlorite: active ingredient in household bleach calcium carbonate: ingredient in antacids sodium hydroxide: lye; used as drain clea…
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in a binary ionic compound, the name of the anion is given as the name …
For the first question: C. -ide For the second question: D. cation, anion
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question 3 when naming ionic compounds the ______ name is followed by t…
Question 3: A. cation, anion Question 4: C. metal cation
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which line do you draw if the atom is coming in front of the atom? norm…
Wedged line
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the rules for naming chemical compounds are known collectively as monik…
Question 1: D. nomenclature Question 2: B. binary
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how are the masses on the periodic table determined? why? most elements…
The masses on the periodic table are average atomic masses, calculated as weighted - averages of the masses of an element's naturally - occurring isotopes based on their relative …
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how much pure acid should be mixed with 6 gallons of a 50% acid solutio…
4
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pregunta 1 de 25 ¿qué dice el principio de le châtelier acerca de alter…
A. Un sistema cuyo equilibrio se ha alterado se desplazará para restablecer el equilibrio.
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¿qué es una constante de equilibrio? a. la cantidad de energía necesari…
B. La relación entre las concentraciones de equilibrio de los productos y las concentraciones de los reactivos.
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¿cuál de las siguientes es la base conjugada de h₃po₄? a. hpo₄²⁻ b. h₂p…
# Explicación breve: La base conjugada de un ácido se obtiene cuando el ácido dona un protón ($H^+$). El ácido $H_3PO_4$ al donar un protón se convierte en $H_2PO_4^-$. # Respuest…
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si el ph de una solución es 5,3 ¿cuál es el poh? a. 9.3 b. 4.7 do. 5.3 …
D. 8.7
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pregunta 1 de 25 ¿cuál de las siguientes es una característica de un ác…
# Breve explicación: Los ácidos fuertes se disocian completamente en agua, liberando iones H⁺. Conductividad en agua es alta debido a la presencia de iones. No reaccionan con agua…
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¿cómo afecta el aumento de temperatura a las colisiones entre moléculas…
B. El número de colisiones con suficiente energía para reaccionar aumenta.
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¿cuál de los siguientes valores de k<sub>a</sub> representa el ácido má…
DO. $K_a = 1.62\times10^{-12}$
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determinar la velocidad de una reacción que sigue la ley de velocidad: …
D. 5,4 (mol/L)/s
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¿qué hacen los ácidos en solución? a. aumentan el ph. b. forman iones h…
D. Aumentan la [H⁺]
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¿cuál es k<sub>eq</sub> para la reacción 2hcl( g)? = h2 ( g)+ cl2 ( g)?…
# Explicación: ## Paso1: Definir constante de equilibrio Para una reacción química general $aA + bB ightleftharpoons cC + dD$, la constante de equilibrio $K_{eq}=\frac{[C]^c[D]^d}…
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multiple choice question some suspected causes of ______ intellectual d…
C. cultural - familial
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¿qué ecuación se utilizaría para calcular la constante de velocidad a p…
# Explicación: ## Paso1: Analizar cada ecuación La ecuación A es la ecuación de Arrhenius para la constante de velocidad en función de la energía de activación, pero no se basa di…
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¿qué es un buffer? a. un par conjugado ácido - base que cambia la veloc…
# Breve Explicación: Un buffer es una solución que contiene un par conjugado ácido - base y su función principal es resistir cambios en el pH cuando se agregan pequeñas cantidades…
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¿cómo se comparan los cambios de temperatura y energía de activación en…
D. Los cambios de temperatura y energía de activación tienen efectos opuestos en la velocidad de reacción.
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¿cómo se calcula el ph de una solución? a. el ph es el logaritmo negati…
# Breve explicación: El pH de una solución se define matemáticamente como el logaritmo negativo de la concentración de iones hidronio [H⁺]. Esto se utiliza para cuantificar la aci…
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pregunta 1 de 25 ¿qué hace que la velocidad de reacción disminuya a med…
# Breve Explicación: La velocidad de una reacción química está directamente relacionada con la concentración de los reactivos. A medida que la reacción progresa, los reactivos se …
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¿qué significa si $k_{eq}=1$? a. los productos y los reactivos se favor…
A. Los productos y los reactivos se favorecen por igual en la reacción.
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¿cuál es $k_a$ para $hno_2(aq)? ightleftharpoons h^+(aq)+no_2^-(aq)$? a…
D. $K_a=\frac{[H^+][NO_2^-]}{[HNO_2]}$
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¿cuál de las siguientes opciones describe mejor una reacción ácido - ba…
D. Ácido + base ⇌ base conjugada + ácido conjugado
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pregunta 1 de 26 ¿cuál de las siguientes opciones define mejor una solu…
D. Una solución con un pH inferior a 7
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what do these two changes have in common? baking cookies cellular respi…
C. Both conserve mass. D. Both are chemical changes.
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what do these two changes have in common? a log decomposing in the wood…
C. Both are chemical changes. D. Both conserve mass.
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what do these two changes have in common? water evaporating from a pudd…
Both are changes of state.
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what do these two changes have in common? stapling an envelope shut usi…
# Brief Explanations: Stapling an envelope and using a magnet to pick up iron are physical changes. They don't change the chemical composition of substances, so mass is conserved.…
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what do these two changes have in common? a dinosaur bone turning into …
C. Both are chemical changes.
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what do these two changes have in common? boiling sugar to make caramel…
Both are chemical changes. Both conserve mass.
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what do these two changes have in common? mixing sand and water mixing …
Both are only physical changes.