Química
Reacciones químicas, estequiometría, estructuras moleculares y propiedades.
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les énoncés suivants portent sur la concentration exprimée en parties p…
a) La concentration en parties par million (ppm) correspond au nombre de parties de soluté dans un million de parties de solution. e) Exprimer la concentration en parties par mill…
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a) une pharmacienne ajoute 50,0 ml deau distillée à 42,0 g dun médicame…
A. \( 75\%m/V \) B. \( 750\ g/L \)
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2h₂o means: two _______________ of water.
molecules
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1. determine the percent composition of potassium dichromate, ( k_{2}cr…
B. \(26.6\%\ K, 35.4\%\ Cr, 38.0\%\ O\)
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fill in the missing word(s) or number(s). 1.place numbers to the ______…
front (or left - hand side)
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fill in the missing word(s) or number(s). -format reactants → _________…
Products
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fill in the missing word(s) or number(s). the coefficients make the equ…
equality (or balance)
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fill in the missing word(s) or number(s). these numbers are called bala…
stoichiometric
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fill in the missing word(s) or number(s). 2 hydrogen molecules react wi…
form (or produce)
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question 24 of 29 is the following reaction balanced? (6.8 points) extr…
Question 24: B. No Question 25: A. 3
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question 21 of 29 how many atoms of hydrogen? (1.4 points) extra conten…
Question 21: A. 3 Question 22: C. 30 Question 23: B. 4
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question 20 of 29 how many total atoms? (1.4 points) extra content ca(c…
C. 15
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explain why it takes longer to cook a large cheese pizza (400g) than it…
It takes longer to cook a large cheese pizza (400g) than a small one (150g) because thermal energy (\(Q\)) is related to mass (\(m\)) by \(Q = mc\Delta T\). The 400g pizza has mor…
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how many total atoms in the following compound. (1.4 points) extra cont…
For \(4K_2CO_3\): D. 24 For \(C_6H_{12}O_6\): D. 24 For \(5Ga_2(Cr_2O_7)_3\): D. 145 For carbon atoms in \(6CO_2+6H_2O ightarrow C_6H_{12}O_6 + 6O_2\): A. 6
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question 15 of 29 what does the arrow in a chemical reaction represent?…
D. all of the above
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question 14 of 29 how many atoms of oxygen? (1.4 points) extra content …
C. 9
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question 11 of 29 how many atoms of calcium? (1.4 points) extra content…
A. 1 ### Question 12
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question 9 of 29 how many atoms of oxygen? (1.4 points) extra content 4…
For \(4K_2CO_3\): D. 12 For \(5Ga_2(Cr_2O_7)_3\): D. 105
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how many atoms of gallium? (1.4 points) extra content 5ga₂(cr₂o₇)₃ a. 5…
For the first question (gallium atoms): B. 10 For the second question (carbon dioxide molecules): A. 6 For the third question (potassium atoms): D. 8
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question 5 of 29 how many atoms of nitrogen? (1.4 points) extra content…
D. 12
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what is a large number written before a compound in a chemical reaction…
1. A. coefficient 2. C. reactants 3. C. products 4. D. 18
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recognizing forms of energy match each form of energy with its correct …
- chemical: involving energy stored in chemical bonds - thermal: involving the motion of atoms - electrical: involving electrical charges - mechanical: involving the position and …
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classify each of the properties as a physical property or a chemical pr…
- **Physical property**: the melting point of sugar, the smell of vinegar, the color of aluminum wire, the luster of silver jewelry. - **Chemical property**: the reactivity of iro…
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classify each of the changes as a physical change or a chemical change.…
- Physical change: slicing an apple, tearing aluminum foil, freezing of water, carving wax - Chemical change: frying a chicken, burning wood, oxidizing of mercury (Hg), bleaching …
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classify the following as chemical or physical changes. match the words…
- First blank (left): a physical change; Second blank (right): changes its appearance but not its molecular composition - Third blank (left): a chemical change; Fourth blank (righ…
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part a which of the following is not a technique that could be used to …
stirring
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if you hold a solid piece of pure gallium metal in your hand, your body…
physical change
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introduction to energy quiz complete shondra takes notes in class. 1. e…
Switch "the energy of moving objects" and "the ability to do work" and place chemical energy under "Forms of energy."
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based on the information in the table above, which liquid, cs₂(l) or cc…
B. \(CS_2(l)\), because it has weaker London dispersion forces
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part a which of the following statements about physical and chemical ch…
All of the above statements are true.
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based on the information in the table above, which liquid, cs₂(l) or cc…
B. \(CS_2(l)\), because it has weaker London dispersion forces
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introduction to energy quiz complete time remaining 57:36 johanna is st…
gravitational potential energy
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the crystal structure of nabr is represented in the diagram above. whic…
D. Crystalline \( \text{NaBr} \) contains no freely moving \( \text{Na}^+ \) and \( \text{Br}^- \) ions, which allows it to be a good conductor of electricity.
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heat is a form of energy related to the motion, or kinetic energy, of t…
water, aluminum, stainless steel, copper, gold
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what is the general equation for an exothermic reaction? a reactants + …
B. Reactants → Products + Energy
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abin is doing work by lifting a bowling ball. which statement could be …
Energy is being transferred from his arm muscles to the ball.
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determine whether each of the following is exothermic or endothermic. d…
- **Endothermic**: Water evaporating from a glass overnight - **Exothermic**: Gas burning in a car, Water condensing on a bathroom mirror after a hot shower
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inside stars in space, the nuclei of hydrogen atoms fuse together to fo…
nuclear energy
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part a identify the energy conversions associated with the following ap…
- Fan: Electrical energy to mechanical energy - Car Engine: Chemical energy to mechanical energy - Solar panels: Light energy to electrical energy - Glowing of a Bulb: Electrical …
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a runner burns $3.49\times10^{3}\text{ kj}$ during a five - mile run. h…
834 Cal
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based on the information in the table above, which of the compounds has…
D. Propanoic acid, because it can form intermolecular hydrogen bonds
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6. at 298 k and 1 atm, br₂ is a liquid with a high vapor pressure, and …
A. forces among \(Br_2\) molecules are stronger than those among \(Cl_2\) molecules
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question 1 what is the empirical formula of a compound that is 17% sodi…
\(NaS_{2}O_{3}\)
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5. a sample of a hard, solid binary compound at room temperature did no…
A. Ionic bonds
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the table below gives information about two isotopes of element y. 1. 3…
The average atomic mass of element \(Y\) is \(20.17\) (rounded to four significant figures).
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4. the attractions between the ccl₄ molecules that hold the molecules t…
B. nonpolar covalent bonds
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7. a 40 g sample of water absorbs 500 joules of energy. how much did th…
The temperature change of the water is approximately \(3.0^{\circ}C\).
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the table above shows the structural formulas and molar masses for thre…
B. Butane < acetone < 1 - propanol
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6. 45 grams of an unknown substance undergoes a temperature increase of…
The specific heat of the substance is \(2.44\space J/(g\cdot^{\circ}C)\) and the substance is ethanol.
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practice it chemical substance that induces a state of drunkenness opia…
intoxicant
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5. copper has a specific heat of 0.385 j/(g·°c). a piece of copper abso…
The mass of the piece of copper is approximately $129.9g$.
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state of physical dependence on a drug caused by repeated usage that ch…
physiological dependence
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severe drug - related problem characterized by impaired control over th…
drug dependence
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practice 11 chemical substances that affect a persons mental or emotion…
psychoactive drugs
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part 2: classify each of the following as elements (e), compounds (c) o…
Diamond (C) - E, Air - M, Krypton (K) - E, Water (H₂O) - C, Ammonia (NH₃) - C, Wood - M, Dry Ice (CO₂) - C, Sugar (C₆H₁₂O₆) - C, Sulfuric Acid (H₂SO₄) - C, Bismuth (Bi) - E, Alcoh…
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4. graphite has a specific heat of 0.709 j/(g·°c). if a 25 gram piece o…
The energy lost by the graphite is $301.325J$ (the negative sign indicates heat loss). Since heat is released, the process is exothermic.
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4. graphite has a specific heat of 0.709 j/(g*°c). if a 25 gram piece o…
The energy lost by the graphite is $301.325J$ (the negative sign in the formula indicates heat loss, and we take the magnitude for the amount of energy lost).
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3. if the temperature of 34.4 g of ethanol increases from 25 °c to 78.8…
$4516J$ (rounded to four significant figures)
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b. determine if its endothermic or exothermic 2. an unknown substance w…
The specific heat of the substance is approximately \(0.67\space J/(g\cdot^{\circ}C)\) and the process is endothermic.
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1. gold has a specific heat of 0.129 j/(g*°c). how many joules of heat …
The amount of heat energy required is $121.905J$ and the process is endothermic.
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4. graphite has a specific heat of ( 0.709 , \text{j/(g}\times^{circ}\t…
The energy lost by the graphite is \(301.325J\) (the negative sign in the calculation just indicates heat loss).
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use with textbook pages 207 - 211. 1 - 5 word equations write the skele…
1. Skeleton: \(H_2+O_2 ightarrow H_2O\); Balanced: \(2H_2+O_2 = 2H_2O\) 2. Skeleton: \(Fe_2O_3 + H_2 ightarrow H_2O+Fe\); Balanced: \(Fe_2O_3 + 3H_2=3H_2O+2Fe\) 3. Skeleton: \(Na …
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question 1 what is the empirical formula c₆h₁₈o₆
\(CH_3O\)
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a. perform calculations using: $(q = mcdot ccdotdelta t)$ 1. gold has a…
1. The heat energy required for gold is \(121.905\) J. 2. The specific heat of the unknown substance is approximately \(0.67\) J/(g·°C).
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the following list contains several properties of ozone (a pollutant in…
- **Physical**: pungent odor, gas at room temperature, bluish color - **Chemical**: very reactive, decomposes on exposure to ultraviolet light
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which of the substances depicted here is a pure substance?
The top - most substance (the one with only one type of molecule) is a pure substance.
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if half of a radioactive isotope decays in one hour, how much of the or…
First question: One eighth of it Second question: \(50\)g Third question: \(25\)g
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classify each of the following mixtures as homogeneous or heterogeneous…
- Homogeneous: urine - Heterogeneous: a Snickers™ bar, soil
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match the vocabulary word with its definition. number of protons in an …
1. atomic number: number of protons in an atom 2. proton: positively charged particles 3. element: substance that contains only one type of atom 4. electron: negatively charge par…
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classify each of the following substances as a pure substance or a mixt…
- Pure substance: pure water - Mixture: a Snickers™ bar, soil, urine
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question 9 (2 points) which of the following is not a particle in the n…
C. electron, D. orbital # Question 10
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classify each type of matter as an element, a compound, a heterogeneous…
- **Element**: aluminum, gold, barium - **Compound**: carbon monoxide, sugar - **Heterogeneous mixture**: soil, orange juice with pulp - **Homogeneous mixture**: air, salt water, …
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which among the following statements is false? a liquid has a definite …
none of the above
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which of the following is not an example of matter? ○ heat from a burni…
heat from a burning candle
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question 1 what is the percent of silver in silver nitrate? question 2 …
Question 1: Approximately \(63.5\%\) Question 2: Approximately \(8.25\%\) Question 3: Approximately \(28.3\%\)
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question 4 (1 point) the presence of harmful substances like chemicals …
C. Contamination # Question 5
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question 3 0.5 pts write the formula for the ammonium perbromate ion. •…
\(NH_4BrO_4\)
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calcium carbonate, ( caco_3 ), decomposes when heated to calcium oxide …
44
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a reaction of 22.85 g of sodium hydroxide with 20.82 g of hydrogen chlo…
\(33.38\)
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write the formula for the ammonium ion. • subscripts and superscripts a…
1. NH4^+ 2. BrO4^-
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magnesium (24.30 g) reacts with hydrogen chloride (x g) to produce hydr…
\(74.64\)
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a reaction of 12.640 g of copper oxide with 0.316 g hydrogen produces 2…
$10.112$
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a reaction of heating calcium carbonate produces calcium oxide and carb…
$4.4$
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when heated, calcium hydroxide and ammonium chloride react to produce a…
13.73
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in any chemical reaction or physical change, the mass of the products i…
B. equal to
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how many grams of of oxygen are in 135.0 g of potassium permanganate? 1…
\(54.67\space g\space O\) (the third option)
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during a chemical reaction, the law of states that the total mass of th…
C. Conservation of mass
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question 25 by using the method of ________we can know how much of each…
spectroscopy
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question 24 what are the building blocks of minerals? 3 pts rocks eleme…
elements
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during a chemical reaction, the law of ________ ________ states that th…
C. Conservation of mass
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how many moles of ammonium nitrate would be required to have 3.55 moles…
1.18 mol \(NH_4NO_3\) (corresponds to the first option \(1.18\space mol\space O\) if we assume a mis - labeling in the options, as the question asks for moles of ammonium nitrate …
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question 22 the most common chemical element in most stars is oxygen hy…
hydrogen
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match the parts of the question that correlate to the following questio…
Given: \(0.300\ g\ Fe_2O_3\); Result: unknown; Units: \(gram/mole\), \(mole/for\ unit\); Substance: \(Fe_2O_3\)
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if the atomic number of an element is 6 and its mass number is 14, how …
$8$ (the fourth option)
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question 9 the relationship of osmotic pressure and the number of solut…
A. greater the number of solute particles, the greater the osmotic pressure
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question 4 where are electrons found in atoms? o in the electron sphere…
in the electron cloud
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question 4 what is the mole ratio of oxygen to sodium acetate in nac₂h₃…
\(2\space mol\space O:1\space mol\space NaC_{2}H_{3}O_{2}\) (the third option)
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question 3 what is the mole ratio of sodium to sodium acetate in nac₂h₃…
1 mol Na : 1 mol \( \text{NaC}_2\text{H}_3\text{O}_2 \) (the second option)
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question 2 what is the mole ratio of hydrogen to sodium acetate in nac₂…
3 mol H : 1 mol \(NaC_2H_3O_2\) (the fourth option)
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question 1 what is the mole ratio of carbon to sodium acetate in nac₂h₃…
2 mol C : 1 mol \(NaC_2H_3O_2\) (the fourth option)