化学
化学反応、化学量論、分子構造、元素の性質。
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2. how many moles are in 3.90 × 10²⁸ molecules of methane (ch₄)?
Approximately \( \boldsymbol{6.48\times 10^{4}} \) moles (or 64800 moles)
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which box represents a homogeneous mixture? a b c d e f a b c d e f
A. Box A
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question 4 (2 points) saved which box represents a compound in the gase…
E. (The box E represents a compound in the gaseous state as it contains molecules of a compound (different atoms bonded) with particles spread out, indicating the gaseous state.)
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for questions s8 - 65 --- fill in the shaded blanks for the elements in…
To solve these fill - in - the - blank questions related to elements (atomic structure), we use the following concepts: - For a neutral atom, the number of protons = the number of…
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for questions 58-65 --- fill in the shaded blanks for the elements in t…
a. 9 ### Question 67
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review 2011 chemistry final semester 1 name pg 3 1. define the followin…
\( 2.5 \times 10^{-4} \) ### Question 20:
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quiz 1 - chemical reactions balance the equation: □ga + □h₂so₄ → □ga₂(s…
Balanced equation: $\boldsymbol{2}\ce{Ga} + \boldsymbol{3}\ce{H2SO4} ightarrow \boldsymbol{1}\ce{Ga2(SO4)3} + \boldsymbol{3}\ce{H2}$ Type of reaction: Single - replacement reactio…
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the following structure is an anion with three possible resonance contr…
### Resonance Structure 1 (Completed): - N: 2 nonbonding electrons (1 lone pair), formal charge = 0 - O: 4 nonbonding electrons (2 lone pairs), formal charge = 0 - S: 6 nonbonding…
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the diameter of a water molecule is 0.000000000033 m. which is the best…
\( 3 \times 10^{-11} \) m (the option with \( 3 \times 10^{-11} \) m)
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4. read the sentence from paragraph 8. \picture a village enclosure in …
B. a protected or separate area ### Question 5
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2c₈h₁₈ + 25o₂ → 16co₂ + 18h₂o the combustion reaction can theoretically…
59.375 (or rounded as needed, e.g., 59.4)
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$$2\\ce{c8h18} + 25\\ce{o2} \ ightarrow 16\\ce{co2} + 18\\ce{h2o}$$ in …
\( 1.6 \)
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li₃n + 3h₂o → nh₃ + 3lioh 12 g of li₃n react with excess h₂o. what is t…
\( \approx 24.8 \) (or more accurately \( 24.7 - 24.8 \) g, but the precise calculation gives approximately 24.8 g)
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zn + 2hbr → znbr₂ + h₂ 32.7 g of solid zinc was dropped into excess hyd…
112
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zn + s → zns 17 g of zn and excess s react in a sealed container. what …
25.3 (approximate value, depending on molar mass precision)
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2mg + o₂ → 2mgo 25 g of mg and excess o₂ react in a sealed container. w…
$\approx 41.4$
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mno₂ + 4hcl → mncl₂ + cl₂ + 2h₂o 9.52 g mno₂ reacts with 16.54 g hcl ac…
\( 7.77 \) (or rounded appropriately, e.g., \( 7.76 - 7.78 \) depending on precision)
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3fecl₂ + 2na₃po₄ → fe₃(po₄)₂ + 6nacl if 23 g of iron(ii) chloride react…
\( \approx 21 \) (or more precisely \( \approx 21.2 \)) g NaCl
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mg + 2hcl → mgcl₂ + h₂ the theoretical yield for hydrogen gas was 2.57 …
17.1 (or 17.12, depending on rounding)
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the following measurements were made to determine the density of a mate…
Low
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convert the condensed formula hccch(ch₃)₂ into its expanded structure. …
``` H | H-C≡C-C-CH₃ | | H CH₃ ``` Expanded structure with all hydrogens drawn explicitly: ``` H | H - C ≡ C - C - H | | H | CH₃ | H | H - C - H | H ``` Or in linear explicit form:…
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2c₄h₁₀ + 13o₂ → 8co₂ + 10h₂o the reaction uses up 16.8 g c₄h₁₀ from the…
\( 3.2 \)
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2c₄h₁₀ + 13o₂ → 8co₂ + 10h₂o what mass of c₄h₁₀ is used when 60.0 g o₂ …
\( \approx 16.9 \)
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2c₄h₁₀ + 13o₂ → 8co₂ + 10h₂o you found that o₂ is the limiting reactant…
\( 26.0 \) (or approximately \( 25.9 \) - \( 26.0 \) depending on rounding steps)
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2c₄h₁₀ + 13o₂ → 8co₂ + 10h₂o 20.0 g c₄h₁₀ burns in 60.0 g o₂. which is …
2
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3ba(no₃)₂ + 2na₃po₄ → ba₃(po₄)₂ + 6nano₃ the reaction is initiated with…
\( 1.22 \)
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3ba(no₃)₂ + 2na₃po₄ → ba₃(po₄)₂ + 6nano₃ what mass of na₃po₄ is used up…
\( 8.78 \)
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3ba(no₃)₂ + 2na₃po₄ → ba₃(po₄)₂ + 6nano₃ ba(no₃)₂ is the limiting react…
\( \boxed{16.1} \)
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3ba(no₃)₂ + 2na₃po₄ → ba₃(po₄)₂ + 6nano₃ 21.0 g ba(no₃)₂ reacts with 10…
1
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3fecl₂ + 2na₃po₄ → fe₃(po₄)₂ + 6nacl 20. g na₃po₄ are used during the r…
$21\ \text{g}$
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3fecl₂ + 2na₃po₄ → fe₃(po₄)₂ + 6nacl what mass of na₃po₄ is used when 2…
\(\approx19.8\) (or more precisely \(\approx19.84\))
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3fecl₂ + 2na₃po₄ → fe₃(po₄)₂ + 6nacl you found that fecl₂ is the limiti…
\( \approx 22 \) (or more precisely \( \approx 21.6 \))
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3fecl₂ + 2na₃po₄ → fe₃(po₄)₂ + 6nacl if 23 g fecl₂ reacts with 41 g na₃…
1
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c₃h₈(g) + 5o₂(g) → 3co₂(g) + 4h₂o(g) the reaction began with 65.0 g c₃h…
\( 23.7 \)
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c₃h₈(g) + 5o₂(g) → 3co₂(g) + 4h₂o(g) knowing that o₂ is limiting, you w…
\( 41.3 \) (or more precise calculation: \( \frac{105}{22.4\times5}\times44.094=\frac{105\times44.094}{112}\approx\frac{4630.87}{112}\approx41.35\approx41.4 \) depending on precis…
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c₃h₈(g) + 5o₂(g) → 3co₂(g) + 4h₂o(g) you determine o₂ is the limiting r…
3.75
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c₃h₈(g) + 5o₂(g) → 3co₂(g) + 4h₂o(g) the combustion of c₃h₈ occurs at s…
2
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2agno₃ + cacl₂ → 2agcl + ca(no₃)₂ the reaction began with 30.00 g cacl₂…
$3.87$
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2agno₃ + cacl₂ → 2agcl + ca(no₃)₂ what mass of cacl₂ is used up when 80…
\( 26.14 \)
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2agno₃ + cacl₂ → 2agcl + ca(no₃)₂ you found that agno₃ is the limiting …
\( \boxed{67.5} \) (Note: More precise calculation: \( \frac{80.00}{169.88} \times 143.32 \approx 67.48 \approx 67.5 \, \text{g} \))
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2agno₃ + cacl₂ → 2agcl + ca(no₃)₂ 80.00 g agno₃ react with 30.00 g cacl…
1
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n₂(g) + 3h₂(g) → 2nh₃(g) the reaction begins with 3.0 l n₂. you found t…
\(1.0\space L\)
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n₂(g) + 3h₂(g) → 2nh₃(g) the reaction begins with 3.0 l n₂ and 6.0 l h₂…
\( 2.0 \, \text{L} \)
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according to the reaction, 3.0 l n₂ can form 6.0 l nh₃. 6.0 l h₂ can fo…
\(H_2\) (the reactant \(H_2\) is limiting because it produces a smaller volume of \(NH_3\) compared to \(N_2\) when fully reacted)
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we can use liter ratios for gaseous reactions at stp. n₂(g) + 3h₂(g) → …
\( 6.0 \, \text{L} \)
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4al(s) + 3o₂(g) → 2al₂o₃(s) the reaction began with 32.0 g o₂. the reac…
$20.0\ \text{g}$
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now that we know which reactant is limiting, we can use it to find othe…
12.0 g
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13.5 g al can produce 25.5 g al₂o₃. 32.0 g o₂ can produce 68.0 g al₂o₃.…
Al (the reactant Al is limiting because it produces a smaller amount of the product \( \text{Al}_2\text{O}_3 \) compared to \( \text{O}_2 \))
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molar masses 4al(s) + 3o₂(g) → 2al₂o₃(s) 26.98 g/mol 32.00 g/mol 101.96…
\(\approx 68.0\ g\) (or more precisely \(67.97\ g\))
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in limiting reactant problems, we normally begin by calculating the amo…
The mass of \( \text{Al}_2\text{O}_3 \) formed is approximately \( 25.5\ \text{g} \) (or more precisely \( 25.49\ \text{g} \)).
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a hydrocarbon fuel is fully combusted with oxygen to yield 23.118 g of …
The empirical formula is \(\boldsymbol{CH}\) (so \(C_1H_1\), but written as \(CH\)). Wait, but wait, maybe I messed up. Wait, let's calculate the mass of C: 0.5253 mol * 12.01 g/m…
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a neurotransmitter consists of carbon, hydrogen, nitrogen, and oxygen. …
10
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the sample contains 0.624 mol c, 1.248 mol h, and 0.078 mol o. determin…
16
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the sample contains 0.624 mol c, 1.248 mol h, and 0.078 mol o. determin…
8
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how many moles o are in 1.246 g o? ? mol o do not round! include lots o…
0.077875
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the 10.00 g sample contains 7.494 g c and 1.260 g h. how many grams of …
\( 1.246 \)
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how many grams of h are present in 1.247725 mol h? ? g h do not round! …
\(1.2576333865\)
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how many grams of c are present in 0.6239945 mol c? ? g c do not round!…
\( 7.4943333 \)
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a carbohydrate contains c, h, and o. a 10.00 g sample of the compound b…
\(1.248046\)
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a carbohydrate contains c, h, and o. a 10.00 g sample of the compound b…
\( 0.6240 \) (more precisely, \( 0.6239945467 \)) but based on the calculation, since 27.462/44.01 = 0.624 (exactly, as 44.01*0.624 = 27.46224, which is very close to 27.462, so t…
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a carbohydrate contains c, h, and o. a 10.00 g sample of the compound b…
0.6239945 (or more precisely, 27.462 / 44.01 = 0.6239945467...)
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what is the empirical formula of the compound? identify the subscript f…
4
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0.1468 mol c : 0.3668 mol h : 0.07344 mol n the moles of each component…
2
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treatment of the nitrogen with h₂ gas resulted in 1.251 g nh₃. how many…
\(0.073456\) (or more precise value from the calculation \(\frac{1.251}{17.03052}\))
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in the course of the combustion analysis of an unknown compound contain…
\(0.3668\)
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based on the previous steps, what is the empirical formula of the menth…
10
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now that we know there are 0.010307 g o, how many moles o are in the sa…
\( 6.441875 \times 10^{-4} \)
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mass sample = 0.1005 g mass carbon = 0.077201 g c mass hydrogen = 0.012…
\( 0.010307 \)
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now do the same for the hydrogen. convert moles h to g h. there are 0.0…
\( 0.0129656 \) (or more precise value with at least six digits, e.g., \( 0.01296562 \))
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since there are two sources of oxygen (the menthol and the air), we hav…
\(0.0772\) (or more precisely, \(0.0064280845\times12.01 = 0.077201294845\approx0.0772\) g C)
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when the sample burns, 0.1159 g h₂o also form. how many moles of hydrog…
\(0.012866\) (or more precise value from \(\frac{0.1159\times2}{18.016}\approx0.012866\))
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menthol, a compound containing c, h, and o, has a strong mint - like sm…
\(0.00642808\)
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question 1 of 49 add lone pairs to compound b. select draw templates mo…
The completed structure has: - Oxygen atom with **2 lone pairs** (4 total non-bonding electrons) - Nitrogen atom with **1 lone pair** (2 total non-bonding electrons) Final structu…
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after combustion with excess oxygen, 12.501 g of a petroleum compound m…
\(2.082\)
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after combustion with excess oxygen, 12.501 g of a petroleum compound m…
\(0.868\) (or more precisely, the value from \(\frac{38.196}{44.01}\) which is approximately \(0.868\) moles)
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the table above provides the values for the standard enthalpy change fo…
B. \(\boldsymbol{\Delta H_f^\circ}\) for \(\boldsymbol{\text{N}_2\text{O}_5(g)}\)
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draw ch₃ch(ch₃)ch₂cho
The structural formula (condensed line-angle structure description and full Lewis structure breakdown): 1. Line-angle structure: A 4-carbon chain, where the first carbon is the al…
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complete the table below by writing the symbols for the cation and anio…
| Ionic Compound | Cation | Anion | | --- | --- | --- | | \( \text{NaCl} \) | \( \text{Na}^+ \) | \( \text{Cl}^- \) | | \( \text{FePO}_4 \) | \( \text{Fe}^{3+} \) | \( \text{PO}_4…
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reaction 1: \\( 2 \\, \\text{o}_3(g) \ ightarrow 3 \\, \\text{o}_2(g) \…
C. \( 2 \text{NO}(g) + \text{O}_2(g) ightarrow 2 \text{NO}_2(g) \)
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22 mark for review \\(\\ce{c_{2}h_{6}(g) + \\frac{7}{2} o_{2}(g) -> 2 c…
C. $\text{H}_2(g) + \frac{1}{2}\ \text{O}_2(g) ightarrow \text{H}_2\text{O}(l)$ $\Delta H^{\circ} = -286\ \text{kJ}$
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| ch₄(g) | -75 | | o₂(g) | 0 | | co₂(g) | -390 | | h₂o(g) | -240 | natu…
C. $\Delta H_{rxn}^{\circ} = [(-390\ \text{kJ/mol}) + 2(-240\ \text{kJ/mol})] - (-75\ \text{kJ/mol})$
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substance | $delta h_f^circ$ (kj/mol) --- | --- $so_2(g)$ | -296.1 $so_…
B. $-99.1\ \text{kJ/mol}_{\text{rxn}}$
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substance | $delta h_f^o$ (kj/mol) caco₃(s) | -1210 cao(s) | -640 co₂(g…
B. +180 kJ
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bond type | average bond enthalpy h - h | 436 kj/mol cl - cl | 243 kj/m…
B. $-185\ \text{kJ/mol}_{\text{rxn}}$
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type of bond | average bond enthalpy (kj/mol) o - o | 150 o = o | 500 2…
C. 300 kJ/mol
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2 co(g) + c(g) → c₃o₂(g) δh° = 127.3 kj/molᵣₓₙ the equation shown above…
B. 63.7 kJ
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$$2 \text{ al}(s) + \text{fe}_2\text{o}_3(s) ightarrow 2 \text{ fe}(s) …
D. 1700 kJ
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$$ce{na_{2}s_{2}o_{3}(aq) + 4 naocl(aq) + 2 naoh(aq) -> 2 na_{2}so_{4}(…
C. 618 kJ of heat is released.
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the heating curve for 1.0 mole of na initially at 25.0°c is shown above…
A. Approximately 13 kJ of heat are absorbed as a result of the increase in potential energy between the Na atoms.
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the table above provides the values for some physical properties of $\\…
C. 2 moles of $\ce{H2S}$
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particulate models of the evaporation of liquid water and the condensat…
C. The amount of energy absorbed by one mole of water molecules as they escape the liquid is equal to the amount of energy released by one mole of water molecules as they come tog…
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convert the condensed formula hccch(ch₃)₂ into its expanded structure. …
The expanded structure is: ``` H | H-C≡C-C-CH₃ | CH₃ ``` Or written with all explicit hydrogens: $H-C≡C-C(CH_3)(CH_3)$ with each $CH_3$ showing: ``` H | H-C≡C-C-H / \ H H / \ H H …
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a student dissolves 8.00 g of $\\ce{nh4no3}(s)$ in 100. g of $\\ce{h2o}…
B. $-5.50\ ^{\circ}\text{C}$
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based on the particle model, which equation best accounts for the chemi…
's see, the black (X) with three white (Y)? Wait, no, the product molecules: each is a black (X) with three white (Y)? Wait, no, the diagram: product has molecules with one black …
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question 17 of 49 propane is an alkane with the molecular formula c₃h₈.…
The complete structure of propane is: $$\ce{H - \underset{\underset{H}{|}}{C} - \underset{\underset{H}{|}}{C} - \underset{\underset{H}{|}}{C} - H}$$ $$\hspace{0.5em} \hspace{0.3em…
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for each row in the table below, decide whether the pair of elements wi…
To solve this, we analyze each row to see if the elements form a molecular (covalent) compound (non - metals combine covalently; metals and non - metals form ionic compounds). ###…
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the graph above shows the changes in temperature recorded for the 2.00 …
B. 25 kJ
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the table provides data for two ch₃oh(l) samples. based on this informa…
D. The $\ce{CH_{3}OH}$ molecules from sample 1 transfer thermal energy to the $\ce{CH_{3}OH}$ molecules from sample 2 through collisions because the average kinetic energy of the …
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two aqueous nacl solutions of equal volume and concentration were kept …
B. The average kinetic energy of the particles in the cooler solution will increase as they collide with the particles from the warmer solution.
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a student carefully drops a 9.0 g solid zn pellet initially at 50.0 °c …
B. Collisions between the water molecules and the surface of the Zn pellet will result in the transfer of energy, increasing the average kinetic energy of the water molecules.