化学
化学反应、化学计量、分子结构与元素性质。
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which statement is false for an electrolytic system with the given $e_{…
The false statement is: The cathode gains mass.
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a current of 20.0 a is applied to a zn⁺² solution. how many seconds wil…
\( \approx 2210\) (or more accurately, using precise calculations: first, moles of Zn: \( \frac{15.0}{65.38} \approx 0.2294\), moles of \( e^- \): \( 0.2294\times2 = 0.4588\), cha…
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solid zn is reduced from znso₄ solution. how many moles of electrons ar…
2 moles of electrons are transferred during the reduction of \(Zn\) (from \(Zn^{2+}\) to \(Zn\)).
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how many minutes will it take to plate the spoon with 0.25 g silver? $\…
$\boxed{0.93}$ (or approximately 0.93 minutes; if there was a miscalculation, maybe I messed up, but according to the steps, this is the result) Wait, no, wait, I think I see the …
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a current of 6.00 a is applied to the chromium(iii) nitrate solution fo…
\( 4.85 \)
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chrome plating is commonly used in vehicle manufacturing for both corro…
3
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practice h₃po₄ h=3 p=4 o=4 pcl₅ p=1 cl=5 c₂h₆o c=2 h=6 o= na₃po₄ na=3 p…
To solve for the number of oxygen atoms in each compound, we use the subscripts and coefficients (if present) to calculate the total number of O atoms. Let's go through a few exam…
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2 points h₃po₄ + koh → k₃po₄ + h₂o k + b₂o₃ → k₂o + b c + s₈ → cs₂ na +…
To solve these chemical equations, we need to balance them by ensuring the number of each type of atom is the same on both sides of the arrow. Let's take one equation as an exampl…
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1. $3 f_{2(g)} + 2 alcl_{3(aq)} \ ightarrow 2 alf_{3(aq)} + 3 cl_{2(g)}…
Approximately \( 2.5 \) moles (or \( \boldsymbol{\frac{1.5 \times 10^{24}}{6.022 \times 10^{23}} \approx 2.5} \) mol) ### Problem 2
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12. draw lewis structures for the following: magnesium phosphide alumin…
To solve this, we determine the chemical formulas by balancing the charges of the ions. ### Magnesium phosphide - Magnesium ion: \( \text{Mg}^{2+} \) - Phosphide ion: \( \text{P}^…
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14. write the molecular formulas of the molecules magnesium chloride po…
To solve this, we determine the chemical formula for each compound by balancing the charges of ions (for ionic compounds) or using prefixes (for covalent compounds) to indicate th…
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which best describes the structure of the poem \safari day in kenya\? f…
free verse with varied line lengths
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i am a halogen. i am a gas at room temperature. and of those halogens t…
Chlorine (Cl)
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i am a main group or representative element. i am located the second pe…
B. Boron (B)
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analyze and extend part a did the result match your predictions about t…
If the prediction was that blowing into water would lower its pH (increase acidity) because exhaled \( \text{CO}_2 \) forms carbonic acid, and the measured pH decreased, then the …
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i am definitely not a halogen. but if all you knew about me was my atom…
Tellurium (Te)
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i am the least massive of all the alkaline earth metals. who am i? view…
Beryllium (Be)
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i am a group 15 element. i am a gas at room temperature. and i am most …
Nitrogen (N)
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of all the group 13 metals, i am the one with the least mass who am i? …
Boron (B)
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i am the only non - metal in group 14. who am i? view periodic table ta…
B. Carbon (C)
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of all the group 13 metals, i am the one with the least mass who am i? …
B. Boron (B)
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of all the group 13 metals, i am the one with the least mass. who am i?…
B. Aluminum (Al)
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3) \\((\\text{nh}_4)_3\\text{po}_4\\) | element | \\(\\#\\) of atoms | …
The number of atoms for N is 3, H is 12, P is 1, O is 4, and total is 20 (as shown in the table above).
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i am the only non - metal in group 14. who am i? view periodic table ta…
B. Carbon (C)
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5) al(oh)₃ element | # of atoms total |
| Element | # of Atoms | |---------|------------| | Al | 1 | | O | 3 | | H | 3 | | Total | 7 |
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of all the group 13 metals, i am the one with the least mass. who am i?…
Boron (B)
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i am the only non - metal in group 14. who am i? view periodic table ta…
Carbon (C)
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of all the group 13 metals, i am the one with the least mass. who am i?…
Boron (B)
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i am the only non - metal in group 14. who am i? view periodic table ta…
Carbon (C)
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i am the halogen located in the second period of the periodic table. wh…
Fluorine (F)
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of all the group 13 metals, i am the one with the least mass. who am i?…
A. Boron (B)
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two different cars, the model s and model t, use different substances i…
The Model T's substance changed phase because the attraction of the molecules was able to overcome their slower movement. Its molecules now move in place.
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when a substance is melting energy is? added taken away
A. Added
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what do we call the way molecules in a substance move around relative t…
○ freedom of movement
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i am the only non - metal in group 14. who am i? view periodic table ta…
Carbon (C)
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when an object freezes, what happens to the energy? ○ it gains energy ○…
It looses energy
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i am a main group or representative element. i am located in the second…
Boron (B)
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i am the least massive metalloid of period 5. who am i? view periodic t…
Antimony (Sb)
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forces shaping earth’s surface – true/false 1. weathering is the proces…
1. A. True 2. A. True 3. A. True 4. B. False 5. A. True 6. A. True 7. A. True 8. B. False 9. A. True
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i am the transition metal that has five more protons than the halogen f…
Titanium (Ti)
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1. choose the sentence in which capital letters are used correctly. (a)…
A. This afternoon, you and I will play basketball with Kathleen and Beth. ### Question 2
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use the periodic table to select the element that best fits each of the…
chromium, calcium, osmium ### Sub - question 2: Which element below is least reactive?
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the half - life of a radioactive kind of americium is 7,380 years. how …
23540
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use the periodic table to select the element that best fits each of the…
A. chromium, D. calcium, E. osmium
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read the claim below. people should eat more fermented foods. select th…
Fermented foods contain helpful organisms that our bodies need to function normally.
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i am the least massive of all the alkaline earth metals. who am i? view…
Beryllium (Be)
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of all the group 13 metals, i am the one with the least mass. who am i?…
Boron (B)
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i am an alkali metal located in the second period of the periodic table…
Lithium (Li)
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part b nomenclature 9. for each of the following molecular compounds, w…
To solve the nomenclature of these molecular compounds, we follow the rules for naming molecular (covalent) compounds: use prefixes (mono-, di-, tri-, tetra-, etc.) to indicate th…
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i am a noble gas. you wont find a member in my family that is lighter t…
Helium (He)
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i am an alkaline earth metal. you will find me in the same period as th…
Barium (Ba)
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7. fill in the blank 1 point 7. type your answer... cucl₂ + type your a…
1, 1, 1, 2 (The coefficients in order for \(CuCl_2\), \(H_2S\), \(CuS\), \(HCl\))
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i am the halogen located in the second period of the periodic table. wh…
Fluorine (F)
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5 fill in the blank 1 point 5. type your answer... zn + type your answe…
The coefficients (from left to right) are 1, 2, 1, 1. So the blanks should be filled with 1, 2, 1, 1 respectively.
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i am an alkali metal located in the second period of the periodic table…
D. Lithium (Li)
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4 fill in the blank 1 point 4. type your answer... h₂o₂ → type your ans…
First blank: 2, Second blank: 1, Third blank: 2
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i am a noble gas. you wont find a member in my family that is lighter t…
Helium (He)
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3 fill in the blank 1 point 3. type your answer... n₂ + type your answe…
The balanced equation is \( \boldsymbol{1}\text{N}_2 + \boldsymbol{3}\text{H}_2 ightarrow \boldsymbol{2}\text{NH}_3 \), so the coefficients (from left to right) are 1, 3, and 2.
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term | information (definition, examples) | picture atom | | sodium ato…
- **Definition**: The smallest unit of a chemical element that retains the element’s properties, consisting of a nucleus (with protons and neutrons) and electrons orbiting the nuc…
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2 fill in the blank 1 point 2. type your answer... h₃po₄ + type your an…
First blank: 1 (coefficient of $\ce{H3PO4}$) Second blank: 3 (coefficient of $\ce{KOH}$) Third blank: 1 (coefficient of $\ce{K3PO4}$) Fourth blank: 3 (coefficient of $\ce{H2O}$) S…
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quiz choose the correct answer for the question. when finished, select …
C) Chemical splash goggles
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life requires about 25 chemical elements. matter is anything that takes…
Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N) ### Sub - Question 2
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question 3 of 12 how did george washington carver use chemistry to help…
- He made other products, like soap and molasses, out of unwanted crops. - He tested the soil and found that Nitrogen needed to be added.
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part b the image models what happened after each cup was placed over an…
- **Water Level**: The water level in the bowl with red liquid (left) and the bowl with yellow liquid (right) may be similar or show a slight difference (e.g., left has a bit more…
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i) vsepr. draw the lewis structure for each of the following and determ…
1. $\text{CBr}_4$: Lewis structure: Central C with 4 single bonds to Br; each Br has 3 lone pairs. No resonance. VSEPR Geometry: Tetrahedral 2. $\text{H}_2\text{S}$: Lewis structu…
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when a formula unit of magnesium sulfide, mgs, is separated into magnes…
ions.
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when a formula unit of magnesium sulfide, mgs, is separated into magnes…
C. ions.
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36 am use the table, along with dimensional analysis, to convert the gi…
\(6000\)
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what is the correct electron dot formula for sodium chloride?\ \ \\(\\b…
$\boldsymbol{[Na]^+ \ [:\ddot{Cl}:]^-}$ (the second option)
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compounds can be classified as covalent or ionic by noting the location…
☑ sodium chloride ☑ potassium bromide ☑ magnesium chloride
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type the correct answer in the box. given: 8co + 17h₂ → c₈h₁₈ + 8h₂o in…
27.8
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select the correct answer. how many moles are contained in $3.131 \\tim…
A. 5.199 mol
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select the correct answer. what is the molar mass of babr₂? a. 217.2 g/…
B. 297.1 g/mol
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select the correct answer. how many particles are in one mole? a. $6.02…
A. $6.022 \times 10^{23}$
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1 type the correct answer in the box. sarah measures out 151 grams of s…
2.36
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given: 2libr + i₂ → 2lii + br₂ calculate the mass of bromine produced w…
239.7 grams
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10 multiple choice 1 point barium (ba) is in which group/ family? trans…
alkaline earth metals
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radon (rn) is in which group/ family? transition metals alkaline earth …
1. noble gases 2. halogens
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nickel (ni) is in which group/ family? alkaline earth metals noble gase…
1. Nickel (Ni): transition metals 2. Potassium (K): alkali metals
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determine if each element below is a metal, nonmetal, or metalloid. eac…
Xenon (Xe): Nonmetal Antimony (Sb): Metalloid Strontium (Sr): Metal
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which of the following is not a condition required by the government to…
95% organic ingredients (option A), outdoor access for livestock (option B), and prohibition of conventional pesticides (option C). There is no requirement for crops to be harvest…
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13 multiple choice 1 point which of the following elements is a metallo…
B. germanium (Ge)
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1 mol sio₂ \\times \\frac{1 mol h₂o}{1 mol sio₂} = 30.0 g h₂o the total…
The total mass of the reactants is $\boldsymbol{140.0\ \text{g}}$ (from $60.0\ \text{g }\ce{SiO2} + 80.0\ \text{g }\ce{HF}$) The total mass of the products is $\boldsymbol{140.0\ …
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the chemical basis of life: atomic structure through chemical reactions…
To complete the table, we define the terms "Element" and "Compound" and provide examples: ### For "Element": - **Definition**: A pure substance consisting of only one type of atom…
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11 multiple choice 1 point alkali metals typically bond with which grou…
11. halogens 12. noble gases
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select the correct answer from each drop - down menu. read this sonnet,…
To solve this, we analyze the sonnet: ### 1. Sonnet Form Edmund Spenser’s sonnets follow the **Spenserian** form (a variant of the sonnet, with a unique rhyme scheme and structure…
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based on the information in the diagram, which conclusion is accurate?t…
A faster rate of physical weathering happens in dry climates
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85 rb 37 use the information for rubidium (rb) provided above. a neutra…
37 protons, 48 neutrons, and 37 electrons.
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6. draw an energy level diagram, as shown in question 5, for each ion. …
7. Metals and nonmetals 8. 1. Alkali metals have 1 valence electron; halogens have 7. 2. Alkali metals form +1 ions; halogens form -1 ions. 3. Alkali metals are soft solids; halog…
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quiz choose the correct answer for the question. when finished, select …
C) Easy to repair
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part e in a lab, strontium (sr) and oxygen (o₂) are combined to produce…
23.2
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how does a food pyramid help individuals eat a healthy diet? a. a food …
healthy diet and what percentage of the diet each group should make up. # Brief Explanations: Food pyramids are visual guides that outline core food groups for balanced eating, al…
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9. complete the following table to write the chemical formula for each …
| Name of compound | Cation | Anion | Chemical Formula | |---------------------------|-----------|-----------|------------------| | (a) copper(I) oxide | $\text{Cu}^+$ | $\text{O}…
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balance the chemical equation. based on the equation, how many grams of…
Balanced equation: $\boldsymbol{\text{Cl}_2 + 2\text{KBr} ightarrow 2\text{KCl} + \text{Br}_2}$ Mass calculation sequence: $\boldsymbol{11.0\ \text{g KBr}} \times \boldsymbol{\fra…
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7. complete the following table to find the charge on the cation in the…
| Compound | Charge on cation | |----------|------------------| | (a) $\text{Cu}_2\text{S}$ | +1 | | (b) $\text{Cr}_2\text{O}_3$ | +3 | | (c) $\text{PbO}_2$ | +4 | | (d) $\text{Ni…
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Question was provided via image upload.
1. Alkali metals have 1 valence electron, halogens have 7 valence electrons. 2. Alkali metals form +1 cations; halogens form -1 anions. 3. Alkali metals are soft, metallic solids …
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given: $2\\ce{c8h18} + 25\\ce{o2} \ ightarrow 16\\ce{co2} + 18\\ce{h2o}…
$84.00\ \text{g}\ \text{CO}_2 \times \frac{1\ \text{mol}\ \text{CO}_2}{44.009\ \text{g}\ \text{CO}_2} \times \frac{25\ \text{mol}\ \text{O}_2}{16\ \text{mol}\ \text{CO}_2} \times …
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21. substance which contains carbon (1 point) inorganic substance micro…
21. D. Organic Substance 22. C. Complete Protein 23. A. Complementary Protein 24. B. Carbohydrate
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13. nutrient levels set for nutrients which lack evidence to develop an…
13. B. AI (Adequate Intake) 14. C. Vitamin 15. D. Inorganic Substance 16. B. Nutrient Toxicity
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5. average daily nutrient intake level for half of the healthy individu…
5. EAR (Estimated Average Requirement) 6. Mineral 7. Non-Essential Nutrient 8. Essential Nutrient