化学
化学反応、化学量論、分子構造、元素の性質。
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clemence began studying a sample of the chemical element einsteinium-25…
Every day, the mass of the sample shrinks by a factor of $0.96$.
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what is the major organic product obtained from the following sequence …
b. pentane
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hich of the following elements has the largest atomic mass? a. oxygen (…
b. Chlorine (Cl)
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5) choose the best answer. which compound contains the highest percent …
$\text{Cu}_2\text{SO}_3$
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c) choose the best answer. a scientist discovers the percent compositio…
For every 100 g of FeSO₄, there are 36.7 g of Fe.
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which sentence better matches the image? bobs mother took him, at four …
Bob's mother took him, at four years of age, to visit the chemistry lab where she worked.
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5. how many atoms are there in 0.55 moles of argon (ar)? a. 3.31x10²³ b…
a. $3.31 \times 10^{23}$ --- For the second question (identifying the element with the largest atomic mass):
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pour brûler une certaine masse de méthane, on a utilisé 125litres d’air…
Volume de méthane brûlé (et donc de $\ce{CO2}$ produit) : $\boldsymbol{12,5\ \text{L}}$ ; Masse de $\ce{CO2}$ : $\boldsymbol{24,55\ \text{g}}$
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question 6 consider an electrolytic cell formed by two half reactions b…
- 0.226 V (corresponding to the option - 0.226 V)
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a scientist discusses the percent composition for iron oxide (fe₃o₄) sh…
For every 100 g of FeSO₄, there are 36.7 g of Fe. --- ### Second Question (Invalid Percent Composition)
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9. ___ (nh₄)₃po₄ + ___ pb(no₃)₄ → ___ pb₃(po₄)₄ + ___ nh₄no₃ 10. ___ se…
9. $4\text{(NH}_4\text{)}_3\text{PO}_4 + 3\text{Pb(NO}_3\text{)}_4 ightarrow \text{Pb}_3\text{(PO}_4\text{)}_4 + 12\text{NH}_4\text{NO}_3$ 10. $\text{SeCl}_6 + \text{O}_2 ightarro…
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1) choose the best answer. what is used to determine the percent compos…
1. molar mass 2. 92%
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1) choose the best answer. what is used to determine the percent compos…
1. B. molar mass 2. A. 92%
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according to the text, which of the following best describes the result…
C. President Nixon removed American troops from Vietnam after several years of protest.
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8. benzene (c6h6) consists of a six membered ring of carbon atoms with …
The Lewis structure of benzene (\(C_6H_6\)) has a six - membered carbon ring with one hydrogen atom attached to each carbon. The two main resonance (Kekulé) structures are: 1. A h…
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name exothermic and endothermic – practice instructions: identify which…
The egg ### 2)
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6. a river flowing through soft rock dissolves some of the rock and car…
6. Chemical weathering, then erosion by water 7. Physical weathering, then erosion by water and gravity
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3. a river carries mud and dirt out of the land it runs through. this i…
3. Erosion 4. Plant roots grow into cracks in rocks 5. Erosion by ice
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u4 - d1 (weathering, erosion and deposition) hi jotsch. when you submit…
1. B. Mechanical weathering 2. D. Deposition
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part 3: solving for neutrons sometimes the periodic table doesnt give y…
1. 4 2. 10
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a chemist has an empty cylinder with a height of 30 cm and a cone - sha…
10 cm
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3. water 1 what type of drinking water should be available for school k…
The right part of the image (the multiple - choice question) is not fully visible, so the specific question and the complete options are unclear. However, based on the left - hand…
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which one of the following reactions is a redox reaction? none of these…
Pb + 2Cl → PbCl₂
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write the formula / formula unit for the following compounds determinin…
| # | Name | Cation (+) | Anion (-) | Formula | |---|--------------------|------------|-----------|---------------| | 1 | Sodium Chloride | $\text{Na}^{1+}$ | $\text{Cl}^{1-}$ | $…
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2) how are fossil fuels formed? what is required?
Fossil fuels (coal, petroleum, natural gas) form from the remains of ancient plants/animals. Over millions of years, organic matter is buried under sediment, then transformed by h…
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the scarcest natural element is ______. astatine uranium francium quest…
1. francium 2. Actinium
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this is the study of measurements. mythology metrology engineering ques…
1. metrology 2. Corson
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20. which of the following lewis dot formations is correct from the opt…
d) $:\ddot{\text{O}}-\ddot{\text{S}}-\ddot{\text{O}}:$
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question 3 1 pts number 137, hypothetically the last element, has alrea…
Question 3: feynmanium Question 4: Oklo
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counting atoms the formula for a compound indicates the elements that m…
1. Aspirin: C = carbon 9, H = hydrogen 8, O = oxygen 4 2. Magnesium hydroxide: Mg = magnesium 1, O = oxygen 2, H = hydrogen 2 3. Paradichlorobenzene: C = carbon 6, H = hydrogen 4,…
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you can become more familiar with the atomic structure of some common s…
| Valence Electrons | Substance | Symbol | Atomic Number | Mass Number | Number of Protons | Number of Neutrons | Number of Electrons | |-------------------|------------|--------|…
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valence electrons & energy levels name ______________________ period __…
| Element | number of valence electrons | number of energy levels used | |---------|------------------------------|-------------------------------| | H | 1 | 1 | | Na | 1 | 2 | | …
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restoration: ased on the data you have collected, who is guilty of degr…
The Factory, The Power Plant, Big Sky Ranch
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ecodetectives: peril river restoration: based on the data you have coll…
The Factory, The Power Plant, Big Sky Ranch, Paradise Organic Farm (select the checkboxes for these entities).
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determine the percentage composition of manganese (mn) in kmno₄. find t…
The percentage composition of manganese (Mn) in \(KMnO_4\) is approximately 34.76%. ### Filling the boxes: - For K: \(39.098\) (atomic mass) \(\times\) \(1\) (number of atoms) \(=…
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a coin contains 0.253 moles of silver (ag). how many silver (ag) atoms …
The number of silver atoms in the coin is \( \boldsymbol{1.52 \times 10^{23}} \) (when calculated as \( 0.253 \, \text{mol} \times 6.02 \times 10^{23} \, \text{atoms/mol} \)).
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4 c. aluminum-27 (atomic number = 13) 4. although electrons have mass, …
1. (For question 4) Electrons are excluded because their mass is negligible compared to protons and neutrons. 2. (For question 5) No, the atom is not neutrally charged; it has a +…
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how many moles of ca(co₃) - (calcium carbonate) are present in a 135.20…
The number of moles of \( \text{Ca(CO}_3\text{)} \) is \( 1.35 \) moles (or more precisely, using the given molar mass approximation \( \frac{135.20}{100.09}\approx1.35 \)). Filli…
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3 use a periodic table of the elements to answer these questions. 1. th…
1. | What the nucleus looks like | What is this element? | How many electrons does the neutral atom have? | What is the mass number? | |------------------------------|------------…
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3 use a periodic table of the elements to answer these questions. 1. th…
### Question 1 (Table Filling) #### Row 1 (First Nucleus) ## Step1: Count Protons and Neutrons Protons (P) = 3, Neutrons (N) = 4. Atomic number = number of protons = 3. So the ele…
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how many molecules are there in 3.36 grams of $nh_3$? calculate the mol…
\( 1.18 \times 10^{23} \) molecules of \( NH_3 \)
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practicing ionic bonding i. writing lewis dot structures a. for each of…
### Part I.a: Writing Lewis Dot Structures for Elements #### Element: Li (Lithium) ## Step 1: Electron Configuration Lithium has an atomic number of 3. The electron configuration …
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mark the following statements as true or false. once text is erased, th…
s: - "Once text is erased, there is no way to see what was written there.": False - "There is no way to detect chemical erasure.": False - "Physical abrasion erasure can be detect…
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2 carbon has three isotopes: carbon - 12, carbon - 13, and carbon - 14.…
6 protons ### Part b
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c. determine what charge the following elements would form if they beca…
### Part c: Determine Ion Charges To determine the charge of each element when forming ions, we use their group number (for main - group elements) or common oxidation states: - **…
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which of the following can be removed by using light at various wavelen…
D. Obliterations
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find the % composition of n and h in nh₃ n blank / blank × 100 = blank …
For N: \(\frac{14.007\ \text{g/mol}}{17.031\ \text{g/mol}} \times 100 = 82.24\%\) For H: \(\frac{3.024\ \text{g/mol}}{17.031\ \text{g/mol}} \times 100 = 17.76\%\)
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how many grams are there in $5.52 \\times 10^{23}$ molecules of $\\ce{n…
The mass of \(5.52\times 10^{23}\) molecules of \(NH_3\) is approximately \(15.62\space g\)
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what is the empirical formula of a chemical with a molecular formula of…
The empirical formula is \( CH \).
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exam 7: moles what is the molar mass of kcl ? keep two places after the…
74.55
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question 13 (1 point) listen which of the following statements is true …
1. Question 13: The client believes the placebo to be effective in pain management. 2. Question 14: Steroids. 3. Question 15: Sarcomas.
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indicate which of the following chemical formulas are empirical or mole…
To determine if a chemical formula is empirical or molecular, we use the following definitions: - **Empirical Formula**: The simplest whole - number ratio of atoms in a compound. …
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match the following words with their correct description avogadros numb…
- Avogadro’s number: \( 6.02 \times 10^{23} \) - particles: atoms, molecules, or formula units - where to find molar mass: periodic table (atomic masses) - molar mass unit: gram/m…
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question 4 (1 point) listen the freezing of a malignancy with a liquid …
1. Question 4: Cryosurgery. 2. Question 5: In situ/benign. 3. Question 6: Is performed to sustain cancer clients and alleviate pain.
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using the set up below, correctly convert 50.0 g of phosphorus (p) into…
First box: 50.0 g P Second fraction numerator: 1 mol P Second fraction denominator: 30.974 g P Result: 1.61 moles P So the setup is \(\frac{50.0\ \text{g P}}{1} \times \frac{1\ \t…
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a diamond is a crystallized carbon (c), known for its extreme hardness,…
Element
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during a lab experiment, john accidentally overheated a penny, causing …
homogeneous mixture
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7) choose the best answer. which mnemonic device is used to help people…
7) OIL RIG 8) yes 9) no
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part a: sentences. use your knowledge of the stems and context clues to…
introvert ### Question 27
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15. what is the rhyme scheme of the poem? * 1 point a. aaaabbbbb b. aba…
b. ABAB CDCD ### Question 16
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what is the weakest reducing agent? \ options: $\\ce{no_3^-}$, $\\ce{cl…
D. Mn²⁺
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what is the strongest oxidizing agent? oxidizing agents: f₂, o₂, mno₄⁻,…
$\text{MnO}_2$
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10) check the box if the phrase or equation describes an acid-base, pre…
1. $\boldsymbol{\text{NaCl}(aq) + \text{AgNO}_3(aq) ightarrow \text{NaNO}_3(aq) + \text{AgCl}(s)}$: Check **Precipitation Reaction** box 2. $\boldsymbol{4\text{Al}(s) + 3\text{O}_…
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20. what is the mass of 2.0 moles of carbon (c)?
The mass of 2.0 moles of carbon is \(24\space g\).
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19. what is the empirical formula of the compound with the molecular fo…
The empirical formula is \(CH_{2}\)
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18. use your scratch paper to work the rr track for this problem: how m…
\( 2.2 \)
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17. use your scratch paper to draw out the rr track for this problem: h…
51.3 grams
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16. which of the following shows the correct number of atoms of each el…
1 magnesium atom, 2 nitrogen atoms, and 6 oxygen atoms (the first option)
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15. what is the percent composition of magnesium (mg) in mgbr₂? 0.132 %…
13.20 % Mg (corresponding to the option "13.20 % Mg")
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14. which of the following has the greatest mass (in grams)? one mole o…
one mole of \(H_2SO_4\)
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part 4: sentences. use your knowledge of the stems and context clues to…
introvert ### Question 27
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13. what is the mass of 1.0000 moles of ca(oh)₂?
The mass of 1.0000 moles of $\ce{Ca(OH)2}$ is $\boldsymbol{74.096\ g}$ (or can be rounded appropriately, e.g., 74.10 g depending on precision needs).
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12. vanillin (vanilla flavoring) has the structure below vanillin what …
The molecular formula of Vanillin is $\boldsymbol{C_8H_8O_3}$
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6. the structures of ethyl butanoate (pineapple scent) is below: the co…
To determine the molecular and empirical formulas of ethyl butanoate, we analyze its structure: ### Step 1: Count Atoms for Molecular Formula From the Lewis structure: - **Carbon …
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13. calculate the molar mass of carbon dioxide (co₂). 60.0 g/mol 44.0 g…
44.0 g/mol (the option with "44.0 g/mol")
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sample of oxygen gas (o₂) has a quantity of 2.0 moles at standard tempe…
44.8 L (corresponding to the option with 44.8 L)
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in which situation would the products remain as separated atoms? (1 poi…
The total potential energy of the separated atoms is less than the total potential energy if the atoms bonded together.
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during photosynthesis, carbon dioxide and water react to produce glucos…
The reaction absorbs energy from the surroundings.
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9. what is the molar mass of calcium hydroxide, ca(oh)₂? 40.1 g/mol 74.…
74.1 g/mol (corresponding to the option with "74.1 g/mol")
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8. a sample contains (1.20 \times 10^{24}) atoms of magnesium. what is …
48.6 g (the option with 48.6 g)
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7. what is the molar mass of oxygen (o)? 6.02 × 10²³ g/mol 16.0 g/mol 8…
The correct option is the one with \(16.0\space g/mol\) (the option labeled with \(16.0\space g/mol\)).
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6. a chemist needs 0.75 moles of nh₃. what mass should be measured? 17.…
12.8 g (corresponding to the option with 12.8 g)
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which statement accurately describes the energy of a block of ice? (1 p…
The kinetic energy of the ice is found in the vibration of the molecules.
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7. predict the products of each reaction. then balance each chemical eq…
s (with balanced equations and reaction types): 1. $\ce{2Al + 3Br_{2} ightarrow 2AlBr_{3}}$; Type: Synthesis 2. $\ce{Cu + 2AgNO_{3} ightarrow Cu(NO_{3})_{2} + 2Ag}$; Type: Single …
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9) choose the best answer. which particle model best represents this sc…
The right particle model (with particles showing longer, more dynamic movement paths) best represents this scenario.
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which energy transformation occurs in an endothermic reaction? (1 point…
B. There is a net flow of energy from the surroundings into the system.
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which energy transformation occurs in an endothermic reaction? (1 point…
A. Energy from the surroundings is stored in the chemical bonds of the products. (Note: Wait, correction. The most accurate is the second option? Wait, no, let's re - check. Wait,…
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unit #1 vocabulary practice part 1: match the word to the correct defin…
1. missiles - o. weapons that are designed to be launched through the air to hit a target 2. convention - l. a large meeting where people gather to discuss specific topics or shar…
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which statement describes what it means for energy to be conserved? ene…
C. Energy released by a reaction is gained by the surroundings.
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4. what is the molar mass of sodium (na)? 11.0 g/mol 22.99 g/mol 45.98 …
B. 22.99 g/mol (assuming the second option is labeled B; if the original options had labels like A, B, C, D with the second being B, else adjust the label as per the original but …
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10) choose the best answer. which particle model best represents this s…
The right particle model (the second rectangular diagram with connected red and green particles)
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21. a motorcycle engine converts 470,000 j of chemical energy into 76,0…
16%
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11) drag and drop the terms with the statements. this decreases the nee…
- This decreases the need for energy in a reaction and increases the reaction rate. → catalyst - If the amount of reactant is increased, then the reaction rate will be faster. → c…
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67.2 liters of nitrogen gas (n₂) at standard temperature and pressure (…
3.0 mol
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use the bond energies to answer the question. h-h = 432 h-o = 467 o=o =…
-509
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quantity unit options amount of substance g number of particles g/mol
| Quantity | Unit Options | |-------------------|--------------------| | Amount of substance | mol | | Mass | g | | Number of particles | (count, related to Avogadro's number) | |…
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15. which type of energy is not considered stored energy? elastic poten…
B. kinetic energy
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3) balance the chemical equation for the combustion reaction by typing …
3) $2\text{C}_4\text{H}_{10} + 13\text{O}_2 ightarrow 8\text{CO}_2 + 10\text{H}_2\text{O}$ 4) $2\text{C}_6\text{H}_6 + 15\text{O}_2 ightarrow 12\text{CO}_2 + 6\text{H}_2\text{O}$ …
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the top row of transition metals in the middle of the periodic table ha…
D. They are likely to form covalent bonds because their electronegativities are close together, making them likely to share electrons.
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1) choose the best answer. what is likely a reactant in a combustion re…
1) $\text{C}_2\text{H}_4$ 2) water