化學
化學反應、化學計量、分子結構與元素性質。
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select the correct answer. iron reacts with atmospheric oxygen to form …
A. \( 4\text{Fe} + 3\text{O}_2 ightarrow 2\text{Fe}_2\text{O}_3 \)
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select all the correct answers. a colorimeter is an instrument used for…
A. The first colorimeter is reliable but not valid. B. The second colorimeter is valid and reliable.
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unit: dimensional analysis \one, two, and more step problems\ direction…
\(7650\space mL\) ### Problem 2:
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what is wrong with this picture? there are many unsafe situations in th…
To solve this, we analyze the lab image for unsafe actions and their consequences: ### Unsafe Situation 3: Eating/Drinking in Lab - **Explanation**: Consuming food/drinks near che…
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for the molecule below, choose the image that accurately does all of th…
The first option (with \( \boldsymbol{\delta^+} \) on \( \boldsymbol{\text{C}} \), \( \boldsymbol{\delta^-} \) on \( \boldsymbol{\text{O}} \), and labeled "Polar Molecule") is cor…
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for the molecule below, choose the image that accurately does all of th…
The second option (with $\delta^-$ on O, $\delta^+$ on C, electrons closer to O, and asterisks on the C=O bonds)
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question 4 1 pts for the molecule below, choose the image that accurate…
(Assuming the correct image (not fully shown) follows the above; if choosing between given, the first option is incorrect (polar label), the second has wrong charges. But ethane i…
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1. what is an acid? 2. why do we say vinegar is acidic? 3. what is h+ a…
An acid is a substance that donates $\ce{H+}$ (protons) in solution (Arrhenius/Bronsted - Lowry) or accepts electron pairs (Lewis). It shows properties like sour taste, pH < 7, an…
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1. what is an acid? 2. why do we say vinegar is acidic?
An acid is a substance that (by Arrhenius: dissociates in water to give $H^+$ ions; by Brønsted - Lowry: donates $H^+$ ions in solution; by Lewis: accepts an electron pair). It ha…
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this image shows multicolored stacks of blocks with uneven heights and …
C. It has a variety of proportions and a dynamic color scheme.
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alquenos 1. nombre los siguientes compuestos: ch₂=ch—c—ch=ch—ch₃ (with …
### Primer compuesto (cadena alifática con dobles enlaces y sustituyentes): #### Paso 1: Identificar la cadena principal (longitud y dobles enlaces) La cadena principal es la que …
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what are the masses of the four different brcl molecules? express the m…
117.882, 115.885, 115.884, 113.887
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34 classify the following as a physical property or a chemical property…
chemical property ### Question 35
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31 if you have 100 particles of hydrogen and 100 particles of oxygen, h…
50
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30 classify iron. * □ (0.5 points) pure substance homogeneous mixture h…
A. pure substance
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28 name the separation method illustrated here. * (0.5 points) enter yo…
Distillation ### Question 29
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27 what kind of mixture is pictured here? * (0.5 points) trail mix: a m…
Heterogeneous mixture (or specifically, a heterogeneous mixture as the components of the trail mix are visibly distinct and not uniformly distributed)
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how does ionization energy change across a period? 1. label your x-axis…
Across a period (left to right), ionization energy **generally increases** (with minor exceptions). For the elements Lithium (Li), Boron (B), Oxygen (O), and Fluorine (F) (in peri…
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26 all of the following are indicators that a chemical change has proba…
Change of state
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24 name the separation method illustrated here. * (0.5 points)
Filtration
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______ properties are dependent on the amount of substance present. * (…
Extensive ### Question 2 (Blank 22)
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18 a ___ is a form of matter that has its own definite shape and volume…
solid ### Question 19
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17 classify the following as a physical property or a chemical property…
physical property
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16 by what method could you use to separate the components of ink? * (0…
Paper Chromatography (or Chromatography)
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perform the calculation to the correct number of significant figures. 0…
121.0
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perform the calculation to the correct number of significant figures. 3…
\( 0.381 \)
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11 what kind of mixtures are pictured here? * (0.5 points) enter your a…
Homogeneous (or Solution) ### Question 12
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9 a student performs an experiment to measure the boiling point of pent…
3.05%
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8. butter melts and burns in a hot frying pan. which of these changes i…
- Melting of butter is a physical change (as it involves a change in state without altering the chemical composition of butter). - Burning of butter is a chemical change (as it in…
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each of the following statements about carbon is true except which one?…
Carbon can form strong hydrogen bonds with other elements.
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part c what determines the types of chemical reactions that an atom par…
the number of electrons in the outermost electron shell
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part b which of these relationships is true of an uncharged atom? optio…
The number of protons is equal to the number of electrons.
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part a molecules such as water are referred to as ____ because they are…
A. polar molecules
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what are the molecular and empirical chemical formulas of a compound ma…
Molecular formula: $\boldsymbol{C_2H_4O}$; Empirical formula: $\boldsymbol{C_2H_4O}$
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how is a poems rhyme scheme marked and identified? upper or lowercase l…
A. upper or lowercase letters, such as "ABAB"
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compound | sketch of molecules in it | group a | h—c≡c—o—h | select (gr…
To solve this, we analyze the molecular structures: ### Compound A The structure is \( \ce{H - C\equiv C - O - H} \) (ethynol). It has a triple bond (\( \ce{C\equiv C} \)) and a h…
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sort the molecular compounds in the table into groups with the same emp…
To solve this, we first need the molecular formulas of all compounds (but since only Compound A is shown here, we assume we need to analyze its empirical formula. However, the pro…
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what are the molecular and empirical chemical formulas of a compound ma…
Molecular formula: $C_6H_{12}O_3$ Empirical formula: $C_2H_4O$
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what are the molecular and empirical chemical formulas of a compound ma…
# Explanation: ## Step1: Count the number of each atom First, we count the number of carbon (C), hydrogen (H), and oxygen (O) atoms in the molecule. - Carbon (C): Let's look at th…
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complete the table below, using the diagram of an atom shown at right. …
To solve this, we recall the properties of subatomic particles: protons, neutrons, and electrons. ### First Row (Charge +1, Mass 1.0 amu, Location A): - **Name**: Proton - **Symbo…
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part a when sugar is dissolved in water, sugar is the ______ and water …
solute; solvent
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complete the table below, using the diagram of an atom shown at right. …
To solve the table about subatomic particles, we use knowledge of protons, neutrons, and electrons: ### First Row (Symbol \( \boldsymbol{\ce{n^0}} \)): - **Name**: Neutron (neutra…
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part e consider two solutions. solution a has a ph of 2, and solution b…
Solution A is 100 times more acidic than solution B.
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complete the table below, using the diagram of an atom shown at right. …
| name | symbol | charge (in multiples of e) | approximate mass (amu) | location on diagram | |------------|--------|----------------------------|------------------------|--------…
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drag the appropriate items to their respective bins. view available hin…
Homogeneous mixture: rum, bronze, honey Heterogeneous mixture: pizza, gravel
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part d when comparing an acid and a base, which statement is true? an a…
An acid has a higher concentration of hydrogen ions and a lower pH than a base. (The option with this description, likely the second option in the list provided in the problem's c…
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une solution dacide sulfurique (h₂so₄) a une concentration de 49 g/1,2l…
D. 0,42 mol/L
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blue vitriol is commonly used in industrial dyeing processes. what is t…
$\boldsymbol{CuSO_4}$
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fahrenheit 451 – reading assignment 6 analysis questions for pages 76-8…
Montag says his wife is dying because Mildred is emotionally and spiritually vacant. She is consumed by the parlor walls (TV - like devices) and lacks real human connection or dep…
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fahrenheit 451 – reading assignment 6 analysis questions for pages 76-8…
Montag says "My wife’s dying" to Faber because Mildred is spiritually and emotionally lifeless. She is consumed by shallow, mind - numbing entertainment (like her parlor - wall "f…
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complete the table below, using the diagram of an atom shown at right. …
To solve this, we recall properties of subatomic particles: ### Step 1: Identify the first particle (charge 0, mass ~1 amu, location A) This is a **neutron**? Wait, no—wait, charg…
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read each description in the first column of the table below. if any ch…
s for each row: 1. An element in Period 2 and Group 1A: Does any element with Z ≤ 92 match? $\boldsymbol{\text{Yes}}$ Symbol: $\boldsymbol{\text{Li}}$ 2. A nonmetal in Group 6A: D…
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using the rules for naming molecular compounds described in the introdu…
Nitrogen dioxide ### Part B
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decide which element probably has a boiling point most and least simila…
Most similar to calcium: magnesium Least similar to calcium: argon
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decide which element probably forms a compound with hydrogen that has a…
- Most similar to oxygen: sulfur (select the radio button for sulfur in the "most similar to oxygen" row) - Least similar to oxygen: potassium (select the radio button for potassi…
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write the chemical formula for this molecule: drag the slider to get a …
\( \text{CH}_4\text{S} \) (or \( \text{CH}_3\text{SH} \))
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write the chemical formula for this molecule: drag the slider to get a …
$C_2H_4O_2$
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write the chemical formula for this molecule:
$\boldsymbol{C_3H_6O_2}$
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fill in the missing information: | symbol | atom or ion? (check all tha…
### For $\boldsymbol{\ce{Mg^{2+}}}$: # Explanation: ## Step1: Determine atom/ion type $\ce{Mg^{2+}}$ has a positive charge, so it's a cation (not neutral atom or anion). ## Step2:…
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after watching a show about submarines, jamil wants to learn more about…
D. What substances dissolve in ocean water?
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fill in the missing information: | symbol | atom or ion? (check all tha…
(for $\ce{Mg^{2+}}$): - atom or ion: cation (check cation box) - number of protons: 12 - number of electrons: 10 ### For $\boldsymbol{\ce{Ru}}$:
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match each diagram to the atom or ion it represents. drag each item to …
- P: Diagram with \(15^+\) and \(15^-\) - \(P^{3+}\): Diagram with \(15^+\) and \(12^-\) - \(P^{3-}\): Diagram with \(15^+\) and \(18^-\) - Mg: Diagram with \(12^+\) and \(12^-\) …
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fill in the missing information: table with columns: symbol, atom or io…
### For $\boldsymbol{\ce{Mg^{2+}}}$: ## Step1: Determine type (cation) $\ce{Mg^{2+}}$ has a positive charge, so it's a cation (not neutral atom or anion). ## Step2: Find protons (…
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which of the following elements is not a metal? view available hint(s) …
D. phosphorus ### Second Question (Which of the following is not an element?):
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what is the atomic number of the element located in group 16, period 2 …
8 ### Part B
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classify the following elements as metal, nonmetal, or metalloid (semim…
- Metal: Mn, Na - Nonmetal: Xe, S - Metalloid: Ge, As
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elements: w, sr, h, ti, be, si, fr; periods: period 1, period 2, period…
Period 1: H Period 2: Be Period 3: Si Period 4: Ti Period 5: Sr Period 6: W Period 7: Fr
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fill in the missing information! | symbol | atom or ion? check all that…
s for each missing cell: - First row protons: $\boldsymbol{5}$, electrons: $\boldsymbol{3}$ - Second row symbol: $\boldsymbol{\text{Mg}}$, protons: $\boldsymbol{12}$ - Third row s…
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classify the following elements as halogens, alkali metals, alkaline ea…
- Halogens: Br, F - Alkali metals: Li, K - Alkaline earth metals: Sr - Noble gases: Ar
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classify the following elements as main group elements, transition meta…
- Main group elements: P, Pb, Ba - Transition metals: Fe, Pt - Inner transition metals: Th
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12. consider the following three step mechanism: cl₂(g) ⇌ 2 cl(g) fast …
Overall reaction: $\boldsymbol{\ce{Cl2(g) + CHCl3(g) -> HCl(g) + CCl4(g)}}$ ### Part 2: Identify Intermediates
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a certain element x has four isotopes. - 94.93% of x has a mass of 31.9…
S
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12. consider the following three step mechanism: $ce{cl2(g) <=> 2 cl(g)…
s: - **Overall Reaction**: $\boldsymbol{\ce{Cl_{2}(g) + CHCl_{3}(g) ightarrow HCl(g) + CCl_{4}(g)}}$ - **Intermediates**: $\boldsymbol{\ce{Cl(g)}}$ and $\boldsymbol{\ce{CCl_{3}(g)…
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part c what is the identity of element x from part b? express your answ…
### Part C To determine the identity of element \( X \), we typically use the atomic number (the subscript in the isotope notation \( _Z^A X \), where \( Z \) is the atomic number…
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part b a certain element x has four isotopes. - 94.93% of x has a mass …
32.07
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how many neutrons are found in one atom of ( ^{16}\text{n} )? express y…
9
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what is the relative atomic mass of the element that consists of the fo…
58.7 amu
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what is the relative atomic mass of a hypothetical element that consist…
Value: $89.8$, Units: amu
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give the nuclear symbol for the isotope of argon for which ( a = 38 )? …
$\ce{_{18}^{38}Ar}$
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part d an atom of sulfur is represented by $\\ce{^{33}_{16}s}$. how man…
17 ### Part E
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part b the atomic number of fluorine is 9. what is the mass number of a…
17 ### Part C
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the atomic number z is the number of protons in the nucleus of an atom …
proton, neutron
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2 select the correct texts in the passage. which two details best shape…
1. Many historical events have occurred at the presidential retreat: the planning of the Normandy invasion, Eisenhower - Khrushchev meetings, Camp David Accords with Menachem Begi…
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food safety many people often ask, \how do i know if foods in the freez…
keep food safe for longer periods
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food safety many people often ask, \how do i know if foods in the freez…
First dropdown: how freezing food
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2. explica por qué la masa permanece constante en una reacción química.…
### Pregunta 2: # Breve Explicación: La ley de conservación de la masa establece que en una reacción química, los átomos no se crean ni destruyen, solo se reorganizan. Esto signif…
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6 sur 32 lors dune neutralisation, 30 ml dune solution de h₂so₄ ont neu…
E. 0,15 mol/L
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respuesta corta: 1. describe cómo se aplica la conservación de la masa …
Al derretirse el hielo (cambio de estado de sólido a líquido), la masa se conserva: la masa del hielo original es igual a la masa del agua resultante, ya que las moléculas de H₂O …
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2. en un ______ cambio, la apariencia de la sustancia puede cambiar, pe…
### Pregunta 2: # Breve Explicación: En química, un cambio físico es aquel en el que la sustancia no pierde su identidad química, solo su apariencia (como estado de agregación, fo…
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2. en un ____ cambio, la apariencia de la sustancia puede cambiar, pero…
### Pregunta 2: # Breve Explicación: En un cambio **físico**, la apariencia de la sustancia puede cambiar, pero su identidad (la naturaleza química de la sustancia) permanece igua…
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completa los espacios: 1. según la ley de conservación de la masa, la m…
destruida
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dans la réaction suivante : 2 al + 3 cl₂ → 2 alcl₃ calculez la masse de…
C. 266 g
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emparejamiento: preguntas | opciones de respuesta 1. ley de conservació…
To solve this matching problem, we analyze each question and option: ### 1. Ley de Conservación de la Masa The Law of Conservation of Mass states that matter is neither created no…
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preguntas de opción múltiple: 1. ¿qué establece la ley de conservación …
b) La masa no es creada ni destruida ### Pregunta 2
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4 sur 32 calculez la masse de 2 moles de dioxyde de carbone (co₂). 2 po…
D. 88 g
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3 sur 32 dans la réaction suivante : caco₃ + 2 hcl → cacl₂ + co₂ + h₂o …
C. 1 mol/L
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sugar will take less time to dissolve in: ○ ice cold lemonade ○ iced te…
hot cup of coffee ### Second Question (Diffusion Rate):
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an example of an atom that has no charge is one that has a) 2 protons, …
A) 2 protons, 2 electrons, and 1 neutron.
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2 sur 32 vous avez 98 g d’acide sulfurique (h₂so₄). calculez le nombre …
D. 1 mol
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graded qu... 0:10:01 elapsed which nonmetal makes up diamond, graphite,…
D) Carbon