化學
化學反應、化學計量、分子結構與元素性質。
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a flask contains 0.410 mol of liquid bromine, br₂. determine the number…
\( 2.47\times10^{23} \) (or more precisely \( 2.46902\times10^{23} \)) molecules
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which orbital and electron can be designated for n=3, l=1, m=-1, s=-1/2…
D. 3py, spinning anti - clockwise
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at a ph of 7, which of the following would be true? multiple choice h⁺ …
A. \(\ce{H+}\) and \(\ce{OH-}\) concentrations would be equal.
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what is the term for a substance that causes a resistance to a change m…
C. Buffer
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there are ______ naturally occurring elements of which ______ are invol…
D. 92; 24 (assuming the last option is labeled D, with the text "92; 24")
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which of the following is an organic molecule? multiple choice naoh c₆h…
B. \( \boldsymbol{\text{C}_6\text{H}_{12}\text{O}_6} \) (assuming the options are labeled A: \( \text{NaOH} \), B: \( \text{C}_6\text{H}_{12}\text{O}_6 \), C: \( \text{NaHCO}_3 \)…
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which term describes a solution that contains more hydroxide ions than …
D. Basic
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water molecules are special. but what makes them so special? multiple c…
C. The bend in their structure (assuming the options are labeled A, B, C, D with A: Because they are liquid, B: Polar bonds, C: The bend in their structure, D: Their abundance)
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the process used to convert liquid vegetable oils to solids by changing…
B. hydrogenation (assuming the second option is labeled B; if the original labels were different, adjust the identifier, but the text is "hydrogenation")
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indicate whether each statement is true or false. 1. the ph scale is a …
False ### 2.
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as hydrogen ion concentration increases, the ph number ________. multip…
C. decreases (assuming the options are labeled A: increases, B: becomes negative, C: decreases, D: stays the same)
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how does a buffer help a solution maintain ph? multiple choice a buffer…
D. A buffer can act like a base if pH is acidic, and it can act like an acid if pH is basic. (Note: Assuming the last option is D as it's the fourth option. If the options were la…
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which of the following is an organic molecule? multiple choice salt (na…
B. Sucrose ($\ce{C_{12}H_{22}O_{11}}$)
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a solution that contains more hydrogen ions (h⁺) than hydroxide ions (o…
acidic (or acid)
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why? working in the science lab can be a lot of fun. mixing random chem…
Alka - Seltzer is added to 100.0 mL of vinegar (at 23.5 °C and 84 kPa); a reaction occurs with gas (bubbles) production, and after the reaction, a 100.0 mL solution is formed at 2…
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check all of the following that are characteristics of buffers. check a…
- $\boldsymbol{\square}$ Can pick up excess $\ce{H+}$ (should be checked) - $\boldsymbol{\square}$ Can release $\ce{H+}$ when $\ce{H+}$ is lacking (should be checked) - $\boldsymb…
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ter 2 exam, substances that do not contain carbon are ______ substances…
B. inorganic; organic
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based on this information, which type of bond is stronger — a covalent …
A covalent bond is stronger. Covalent bonds are intramolecular (within a molecule, e.g., O - H in $\ce{H_2O}$) and involve electron - sharing to hold atoms together. Hydrogen bond…
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multiple choice question how do the number of valence electrons and the…
D. same valence electrons, different number of energy levels (assuming the last option is labeled D; if the original options had labels like A, B, C, D with the last one being "sa…
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lets quickly review the differences between covalent bonds and hydrogen…
### Covalent Bond: - holds the atoms in a single water molecule together - formed when two atoms share electrons ### Hydrogen Bond: - formed from an attraction between a partial p…
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which gas forms 21% of earths atmosphere? a. argon b. carbon dioxide c.…
D. oxygen
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the number of in an atoms nucleus is equal to its atomic number.
protons
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true or false question true or false: atomic mass does not always incre…
True
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ionization energy is the energy required to remove an electron from an …
According to Coulomb’s Law (\( F = k\frac{q_1q_2}{r^2} \)), the force (\( F \)) between the nucleus (positive charge, \( q_1 \)) and the outermost electron (negative charge, \( q_…
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in the modern periodic table, elements are arranged by increasing . nee…
atomic number (or proton number)
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____, ____, and ____ are the three basic subatomic particles that make …
Protons, Neutrons, Electrons
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which is the weighted average mass of all naturally occurring isotopes …
B. average atomic mass
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for atoms to be different isotopes of an element, they must have differ…
B. neutrons
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what is the term for the small, positively charged center of an atom? ○…
A. nucleus
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a(n) is the smallest particle of an element that retains the element’s …
atom
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4. give five examples of chemical transformations (changes) that you ma…
1. Burning of Wood (Campfire) - New substances (CO₂, ash) formed. 2. Rusting of Iron (Bicycle Chain) - Iron oxide (rust) formed. 3. Cooking an Egg - Protein denaturation, new stru…
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adding a proton to the nucleus of an atom (or removing one), and an ele…
element
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unit examinations content page 26 of 51 question 25 which abbreviation …
B. CHF—cardiogenic heart failure
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(1 of 10) a 4.0 molar solution of glucose (c₆h₁₂o₆) would have an osmol…
an osmolarity of 4.0
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fred has been having severe memory difficulties of late, and his doctor…
A. PET
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lab questions 1. does a substance have to be water soluble to be classi…
No ### Question 2 #### Ionic
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the atomic weight of nitrogen is very near 14, indicating that most nit…
B. 7
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click to fix any capitalization errors below. click \submit answer\ if …
Whenever Luca Paguro's chemistry teacher sat in the dunking booth at the school's Spring Fling, ticket sales were huge.
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ch 2 chemistry reading quiz - chapter 2 question 5 part a ______ is an …
C. Carbon dioxide
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read each question. follow the instructions to answer the questions. 1.…
C. a combination of substances that keep their own properties ### Question 2
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part a which element do organic compounds always contain? ○ n ○ c ○ h ○…
B. C
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reading quiz - chapter 2 question 7 part a if a solution has a ph that …
A. acidic
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part a a solution containing more hydrogen ions than hydroxide ions is …
D. acidic (assuming the options are labeled as A. neutral, B. in equilibrium, C. basic, D. acidic)
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when would it be most appropriate to use chemical sterilization? ○ for …
C. For instruments that are sensitive to heat and steam
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multiple choice question chemical sterilization is also known as ______…
B. cold
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ionic bonds, such as in sodium chloride, ______ are bonds created by th…
are formed by the association of ions with opposite charge
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4. if you wait for a long time, what will happen to the color of the wa…
The water throughout the pie plate will be the same color as the initial drop.
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q3. you have a round pie plate filled with water. you carefully release…
A. Dye molecules move in all directions and since most directions take them away from the drop, they spread out.
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a covalent compound has the formula sebr₂. complete the table to determ…
- Selenium: 1 - Bromine: 2 - Compound name: Selenium dibromide
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which of the following works by permeating the instrument wrappings in …
O Moist heat (steam)
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n ionic compound is named rubidium arsenate. complete the table to dete…
(Table and Formula): ### Table: - Rubidium: Charge \( +1 \), Total Charge \( +3 \), Number \( 3 \) - Arsenate: Charge \( -3 \), Total Charge \( -3 \), Number \( 1 \) ### Formula: …
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an ionic compound is named ammonium phosphide. complete the table to de…
(Table Values and Formula): - Ammonium: Charge = $+1$, Total Charge = $+3$, Number = $3$ - Phosphide: Charge = $-3$, Total Charge = $-3$, Number = $1$ - Formula: $\ce{(NH4)3P}$
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why might a psychologist use an electroencephalogram (eeg)? to produce …
To explore the possibility of abnormal electrical activity within the brain
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select all that apply which of the following methods are used to steril…
B. Autoclaving, D. Chemical (cold) processes
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what is the primary method for sterilizing equipment and instruments? ○…
C. Autoclaving
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an ionic compound is named potassium hypobromite. complete the table to…
(Table and Formula): ### Table: | Ion | Charge of One Ion | Total Charge of Ion(s) in Compound | Number of Ion(s) in Compound | |--------------|-------------------|---------------…
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an ionic compound is named magnesium selenite. complete the table to de…
### Table Completion: | Ion | Charge of One Ion | Total Charge of Ion(s) in Compound | Number of Ion(s) in Compound | |------------|-------------------|---------------------------…
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a polyatomic ion has the formula mno₄⁻. what is the name of this ion?
Permanganate ion (or specifically, the permanganate anion)
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a polyatomic ion has the formula cn⁻. what is the name of this ion?
cyanide ion
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a polyatomic ion is named thiosulfate. what is the formula of this ion?
\(S_2O_3^{2-}\)
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a polyatomic ion has the formula c₂h₃o₂⁻. what is the name of this ion?
acetate ion (or ethanoate ion)
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a polyatomic ion is named ammonium. what is the formula of this ion?
$\boldsymbol{\text{NH}_4^+}$
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a polyatomic ion is named hydroxide. what is the formula of this ion?
The formula of the hydroxide ion is $\boldsymbol{\ce{OH^-}}$.
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which of the following apply to reprocessing equipment in a medical off…
- It should be routinely monitored. - It must be done according to the manufacturer’s recommendations. - Responsible personnel should wear appropriate PPE. - Equipment must be cle…
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an ionic compound has the formula scbr₃. complete the table to determin…
### Table Filling: - Scandium: Charge of One Ion = \( 3 \), Total Charge of Ion(s) = \( 3 \), Number of Ion(s) = \( 1 \) - Bromine: Charge of One Ion = \( -1 \), Total Charge of I…
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ionic compound has the formula mnbr₂. complete the table to determine t…
### Table Filling: - Manganese: Charge of One Ion = $2$, Total Charge = $2$, Number of Ions = $1$ - Bromine: Charge of One Ion = $-1$, Total Charge = $-2$, Number of Ions = $2$ ##…
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name 5 elements that we dont know what the state of matter is at room t…
Tennessine (Ts), Oganesson (Og), Moscovium (Mc), Nihonium (Nh), Livermorium (Lv)
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an ionic compound has the formula cu₃p₂. complete the table to determin…
# Explanation: ## Step1: Determine number of ions For \( \text{Cu}_3\text{P}_2 \), number of Cu ions: 3, number of P ions: 2. ## Step2: Find charge of P ion Phosphorus (P) in ioni…
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an ionic compound has the formula cu₃n. complete the table to determine…
(Table Completion): - Copper: Charge of One Ion = 1, Total Charge of Ion(s) = 3, Number of Ion(s) = 3 - Nitrogen: Charge of One Ion = -3, Total Charge of Ion(s) = -3, Number of Io…
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an ionic compound has the formula pbse. complete the table to determine…
### Table Values: - Lead: Charge of One Ion: \( +2 \), Total Charge: \( +2 \), Number of Ions: \( 1 \) - Selenium: Charge of One Ion: \( -2 \), Total Charge: \( -2 \), Number of I…
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for each of the following, circle the correct element. metal smallest i…
To solve these problems, we analyze each category based on periodic table properties: ### 1. Metal Metals are typically on the left/center. From options (Li, Si, S), **Li (Lithium…
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an ionic compound has the formula au₂se₃. complete the table to determi…
### For Gold (Au) and Selenium (Se) in $\boldsymbol{Au_2Se_3}$: #### Step 1: Determine charge of Selenium ion Selenium is in group 16, so its ion is $Se^{2-}$ (charge = $-2$). ###…
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for each of the following circle the correct element. li bi s metal n p…
Let's analyze each row: 1. **Li, Bi, S - metal**: Li (Lithium) is an alkali metal. Bi is a metalloid, S is a non - metal. So Li is correct (circled as in the image). 2. **N, P, As…
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element lewis structure bohr model # of valence e- ____ # of e- ____ be…
For Lewis Structure (number of valence electrons): 2 For Bohr Model (number of electrons): 4
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an ionic compound is named copper (i) oxide. complete the table to dete…
### Table Filling: - Copper (I): Charge of One Ion: \( +1 \) Total Charge of Ion(s) in Compound: \( +2 \) Number of Ion(s) in Compound: \( 2 \) - Oxygen: Charge of One Ion: \( -2 …
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19. based on the concept of periodic trends, answer the following quest…
F (Fluorine)
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an ionic compound is named tin (ii) phosphide. complete the table to de…
$\text{Sn}_3\text{P}_2$ ### Table Completion: | Element | Charge of One Ion | Total Charge of Ion(s) in Compound | Number of Ion(s) in Compound | |---------------|----------------…
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22 sur 32 tu utilises 20 g de dichlorure de magnésium pour la réalisati…
D. 2,12 mol/L
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an ionic compound is named iron (ii) bromide. complete the table to det…
- Iron (II) Charge: $+2$, Total Charge: $+2$, Number of Ions: $1$ - Bromine Charge: $-1$, Total Charge: $-2$, Number of Ions: $2$ - Formula: $\boldsymbol{\text{FeBr}_2}$
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an ionic compound is named chromium (ii) oxide. complete the table to d…
The formula for chromium (II) oxide is \( \text{CrO} \). Table filled: - Chromium (II) charge: \( +2 \), total charge: \( +2 \), number of ions: 1 - Oxygen charge: \( -2 \), total…
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chapter 10: skill - builder due sunday by 11:59pm points 10 submitting …
### Part (a) - HF - KF Buffer #### Brief Explanations: - A buffer consists of a weak acid and its conjugate base (or a weak base and its conjugate acid). Hydrofluoric acid (HF) is…
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18 based on the concept of periodic trends, answer the following questi…
Na
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1. locate the circled molecule of rsq in model 1. a. find a second rsq …
For the sub - question 1b (assuming the above analysis), the number of atoms in a molecule of RSq is 3. (Note: For other sub - questions, the approach would vary. For example, for…
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messages travel between neurons through bodily reflexes. a chemical tra…
B. a chemical transmission system.
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19. based on the concept of periodic trends, answer the following quest…
F (Fluorine) ### e. Which element has the least metallic character?
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an ionic compound is named cobalt (iii) phosphide. complete the table t…
The formula for cobalt(III) phosphide is $\boldsymbol{\text{CoP}}$. - Cobalt(III) charge: $+3$; Total charge from Co: $+3$; Number of Co ions: $1$ - Phosphide charge: $-3$; Total …
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20 based on the concept of periodic trends, answer the following questi…
s: a. $\boldsymbol{S}$ (Sulfur) b. $\boldsymbol{Au}$ (Gold) c. $\boldsymbol{Au}$ (Gold)
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18. based on the concept of periodic trends, answer the following quest…
Na ### Part b
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a chemical message that prevents or decreases the likelihood that a rec…
C. inhibitory
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which term correctly describes the relative position of the two substit…
ortho
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elements and compounds - 7.6a, 7.6b based on images, scientists believe…
Since no specific question is provided about this text, it's not possible to give a targeted answer. If you want to know about the scientific concepts (like elements/compounds in …
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unit 1 hw: atomic structure & properties part i: short response use the…
The empirical formula is \( \text{SiO}_4 \)? Wait, no—wait, recalculating: Wait, 14.0 g Si is \( 14 / 28.09 \approx 0.5 \) mol. 32 g O is \( 32 / 16 = 2 \) mol. So ratio Si:O is \…
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what product is formed in the hydration reaction shown below? alkene st…
The first option (the one with \(OH\) attached to the carbon with two methyl groups in the product structure)
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what is the structure of 3-methylcycloheptene? options with chemical st…
The second option (the one with the 7 - membered ring, a double bond, and a $CH_3$ group attached to the appropriate carbon)
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14. milk souring p/c c 15. gasoline burning p/c c 16. ice melting p/c p…
**: C ### 15. Gasoline burning Burning gasoline (hydrocarbons + O₂ → CO₂ + H₂O) produces new substances.
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the contents on a box of cupcakes lists partially hydrogenated soybean …
B. It decreases the percent of unsaturation that is present.
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2. a cup of metal beads was measured to have a mass of 430 grams. by wa…
The metal is Copper (density calculated as $\approx 8.96\ \text{g/mL}$, matching copper's density).
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the molecules cis-2-pentene and trans-2-pentene are an example of a pai…
B. stereoisomers
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3. the gas state of a substances that is usually a solid or a liquid at…
vapor
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8. calculate the density in g/l if a block of silver (ag) has a mass of…
\( \approx2.04\times10^{-5}\space g/L \) (rounded to three significant figures)