Chemie
Chemische Reaktionen, Stöchiometrie, Molekülstrukturen und Elementeigenschaften.
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if you mix two clear, colorless liquids together, which of the followin…
C. A solid appears in the tube and settles to the bottom.
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2. chemicals are used for preserving food products. it helps them by in…
Biochemist
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select the correct answer. what is the greatest difference between ben …
B. tone
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two reactants are mixed in a test tube, and the test tube becomes very …
heat
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a solid that forms and settles out when two or more solutions are mixed…
c. precipitate
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a solid and a liquid are mixed in a test tube. which of the following o…
A. The mixture changes color to a deep blue. C. The mixture starts to fizz as a gas is released. D. The test tube becomes colder as the substances are mixed.
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when zinc metal is mixed with hydrochloric acid, vigorous production of…
Hydrogen gas
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which of the following correctly describes changes in energy during a c…
B. Energy may be either absorbed or released during a reaction.
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if a powdered solid were mixed with a liquid which of the following obs…
d. The mixture starts fizzing and releasing gas.
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12 multiple choice 5 points model of a na atom is shown below: b. what …
1. Option Text
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15 multiple choice 5 points the image shows a model for a lithium atom:…
4
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12. the substances that start a chemical reaction are called ____. ente…
reactants
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11. the substances produced in a chemical reaction are called ______.
products
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10 multiple choice 5 points the table shows the number of each of the t…
C. 1 and 4
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10. during a chemical reaction a chemical bonds break. b matter is dest…
A. chemical bonds break
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5) how long do emotions last chemically in the body? (a) 90 minutes (b)…
C. 90 seconds
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9. when lead nitrate and potassium iodide are mixed, what color precipi…
Yellow
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41 - 55: number of neutrons for sulphur-35
19
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8. if you heat a red powder to a high temperature and observe that it c…
TRUE
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7. when zinc metal is mixed with hydrochloric acid, vigorous production…
Hydrogen gas
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6. which of these metals is least likely to be involved in chemical rea…
A. gold (Au)
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5. what compound forms when zinc reacts with sulfur? enter the answer s…
Zinc sulfide (ZnS)
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4. the ability of matter to easily combine chemically with other substa…
A. reactivity
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3. which of these is a chemical change? a water evaporating b dissolvin…
d. baking a cake
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2. which of the following is/are true? a mixing an acid with base to pr…
C. Tarnishing of silver is a chemical change
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1. all of the following are chemical changes except a iron rusting, b i…
B. ice cubes melting
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remove the two oxygen atoms and observe that the claws get replaced by …
Energy released to form one O - H bond: 463 kJ/mol Energy released to form one H₂O molecule: 926 kJ/mol Total energy released to form two H₂O molecules: 1852 kJ/mol
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click the \investigation\ tab. the energy required to break a chemical …
Total energy required to break both single H - H bonds: 872 kJ/mol Total energy required to break both bonds in the O=O molecule: 498 kJ/mol Total energy absorbed to break all the…
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element #72 hafnium has an atomic mass of 178. how many neutrons are th…
106
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consider these equations. ch₄(g) → c(s) + 2h₂(g) δh₁ = 74.6kj c(s) + 2c…
represents the overall enthalpy of reaction
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consider these equations. ch₄(g) → c(s) + 2h₂(g) δh₁ = 74.6kj c(s) + 2c…
has a magnitude that is less than that of B
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consider these equations. ch₄(g) → c(s) + 2h₂(g) δh₁ = 74.6kj c(s) + 2c…
74.6 kJ
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what can a person do to limit exposure to x - rays? wear sunblock avoid…
wear a protective lead vest
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which option correctly shows the concentration of h₃o⁺ ions in pure wat…
$1.0\times10^{-7}\ mol/L$ (corresponds to the third - option from the list in the question)
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which pattern in electronegativity do elements in the periodic table di…
Electronegativity increases from left to right within a row of the periodic table.
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use the reaction to answer the question. hcl + h₂o → cl⁻ + h₃o⁺ which s…
HCl is an acid, and Cl⁻ is its conjugate base
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which statement best describes the difference between a substance with …
The substance with the lower pH has 1,000 times as many hydrogen ions per volume of water.
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how are acids and protons related? (1 point) acids are substances that …
An acid can donate protons to a base when they react.
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exercise 3.31 - enhanced - with expanded hints view available hint(s) r…
Molecular: $\text{PCl}_3$, $\text{CH}_4$ Ionic: $\text{SrF}_2$, $\text{Fe}_2\text{O}_3$
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which of the following are chemical changes? select all correct answers…
Wood burning to form ash, Hydrogen and oxygen forming water
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6 which of the following is an important thing to consider when choosin…
6. Whether there are monthly fees or minimum balance requirements. 7. You'll likely have 24 - hour access to your money.
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select the correct terms to complete the statement: a homogeneous mixtu…
D. Homogeneous, heterogeneous
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convert word equations into chemical equations classify each chemical r…
1. S, $Mg + S ightarrow MgS$ 2. D, $2NaOH ightarrow Na_2O + H_2O$ 3. DD, $CaS+2HCl ightarrow CaCl_2 + H_2S$ 4. SD, $Cl_2 + SrI_2 ightarrow SrCl_2+I_2$ 5. D, $2Ag_2O ightarrow 4Ag …
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select the correct terms to complete the statement: an intensive proper…
Intensive, physical
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what is the purpose of a detailed chemical analysis in the context of m…
C. To identify the components
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if an electron is promoted into a higher energy level within an atom, w…
create more half - filled orbitals that are available to accept or share electrons with different atoms
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what does the acronym \oil - rig\ stand for in the context of redox rea…
Oxidation is losing electrons; reduction is gaining electrons.
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which option correctly describes an oxidation - reduction reaction? a t…
a transfer of electrons
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porcelain originated in china around 2,000 years ago, but its productio…
B. It emphasizes the longstanding European desire to create porcelain themselves.
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16. in the diagram below, label each phase and phase change indicated. …
1. Melting (Solid to Liquid) 2. Liquid 3. Condensation (Gas to Liquid) 4. Vaporization (Liquid to Gas) 5. Solid
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artificial turf is composed of blades of fake grass. between each blade…
B. harmful
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multiple choice 1 point in which of these compounds are there twice as …
$H_2SO_4$
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13. label each of the following as an element, compound, homogeneous mi…
a. Element b. Homogeneous mixture c. Element d. Heterogeneous mixture e. Homogeneous mixture f. Compound g. Heterogeneous mixture h. Compound
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how many hydrogen (h) atoms are in 4nh₃? 1 4 3 12
D. 12
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21 multiple choice 1 point how many total atoms make up 2ba(io₃)₂? 18 1…
18 (corresponding to the first option)
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after which action would the concentration of a solution remain constan…
B. removing solution from the container
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atomic structure worksheet draw an atom below and label the following: …
| Subatomic Particle | Electrical Charge | Location in Atom | Relative mass (amu) | | ---- | ---- | ---- | ---- | | Electron | - 1 | Outside the nucleus in electron - shells | ~0 …
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a mother finds her daughters mug of hot cocoa on a table an hour after …
The cocoa was mixed with hot water, but some cocoa settled as it cooled because the solubility went down
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multiple choice 1point decide if each reaction is balanced or not balan…
Balanced
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which statement is the best explanation for the graph? (1 point) as tem…
As temperature rises, gas particles are moving faster and may leave the solution
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19 multiple choice 1 point a student mixes 4 grams of hydrogen with 32 …
36 grams
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which option is a microscopic property that helps determine whether or …
polarity
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which substance is an example of a nonpolar compound? (1 point) food co…
vegetable oil
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what are the products in the following chemical equation? ch₄ + 2o₂ → c…
C. $CO_2 + 2H_2O$
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which of the following molecules has the formula ch₂o? a o c=h o b h c=…
B.
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16 multiple choice 1 point ca(oh)₂ + h₂so₄ → caso₄ + 2h₂o 140g? 165g 32…
57
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ca(oh)_2 + h_2so_4 = caso_4 + 2h_2o 18.5g 3.2g how many grams of h_2so_…
$1.33$ (assuming the first option in the multiple - choice is $1.33$)
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procedure 1|100.0 g|97.5 g procedure 2|100.0 g|102.5 g assuming the stu…
Procedure 1: One of the products was a gas that escaped into the air. Procedure 2: A gas from the air reacted with one of the other reactants.
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element r has 3 isotopes: isotope atomic mass (amu) abundance (%) r - 3…
The missing abundance is 4.50%, and the average atomic mass of Element R is 35.409228 amu
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unit 3 test - atoms and the periodic table 20. which picture is the boh…
d.
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element q has the following isotopes: isotope atomic mass (amu) abundan…
$102.50$
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element x has three isotopes: • x - 39: atomic mass = 38.96 amu, abunda…
$39.10$ amu
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8 multiple choice 1 point what type of maintenance is the best way to r…
E. Water Change
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element b has two isotopes: b - 35: atomic mass = 34.97 amu, abundance …
$35.45$
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an unknown element has these isotopes: • a - 28: atomic mass = 27.98 am…
$28.09$
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element z has the following isotopes: • z - 62: atomic mass = 61.93 amu…
$62.45$
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unit 3 test - atoms and the periodic table 14. how many neutrons does t…
# Explicaciones paso a paso: ## Paso 1: Encontrar el número de protones de litio El número atómico del litio es 3, lo que significa que tiene 3 protones. ## Paso 2: Calcular el nú…
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unit 3 test - atoms and the periodic table 14. how many neutrons does t…
# Explicación paso a paso: ## Paso 1: Encontrar el número de protones del litio El número atómico del litio es 3, lo que significa que tiene 3 protones. ## Paso 2: Calcular el núm…
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multiple answer 4 points which of the following are transition metals? …
Tin, Titanium, Tungsten, Chromium, Silver, Zinc
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atomic structure worksheet list the 3 subatomic particles, their charge…
| Element | Symbol | Atomic Number (Z) | Atomic Mass (A) (rounded) | # of Protons | # of Electrons | # of Neutrons | | ---- | ---- | ---- | ---- | ---- | ---- | ---- | | Sodium | …
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questions 8-12: calculations. use the information below to answer the f…
$2.36\ g/mL$ ### Question 9
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2 multiple choice 4 points which of the following shows a pair of halog…
C. F and Br
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21 multiple choice 1 point what water quality chemical test would you p…
D. Salinity
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7 test - atoms and the periodic table how many valence electrons does g…
# Explicación: ## Paso1: Nivel de valencia de los elementos del Grupo 13 Los átomos de los elementos del Grupo 13 tienen 3 electrones de valencia. ## Paso2: Número de electrones e…
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balancing chemical equations - worksheet #1 balance the following chemi…
1. $2\text{Al}(s) + 6\text{HCl}(aq)=2\text{AlCl}_3(aq)+3\text{H}_2(g)$ 2. $2\text{K}(s)+2\text{H}_2\text{O}(l)=2\text{KOH}(aq)+\text{H}_2(g)$ 3. $3\text{Mg}(s)+\text{N}_2(g)=\text…
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counting atoms practice identify the number of atoms for each element i…
| Compound | $Mg$ | $O$ | $H$ | $Ca$ | $C$ | $Ba$ | $P$ | $Fe$ | $N$ | $Cl$ | $Na$ | $S$ | $Sr$ | $F$ | $Cu$ | | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---…
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4. what is true about protons? a. are negative b. are positive c. are n…
4. b. Are positive 5. b. Transition Metals 6. b. Left
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1 matching 4 points what groups are the following elements located in? …
Fr: Group 1; Ca: Group 2; P: Group 15; Sulfur: Group 16; Iodine: Group 17
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14 multiple choice 1 point activated carbon charcoal granules absorb to…
# Breve explicación: La carbón activado actúa a través de un proceso químico al absorber químicos tóxicos como la amoníaco. Un filtro químico es aquel que utiliza reacciones quími…
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3. which element is a cation? a. (p) phosphorous b. (ar) argon c. (bi) …
d. (Al) Aluminio
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question 27 (1 point) which of the following is not a properties of wat…
C. Does not dissolve salt
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which compounds have the empirical formula ch₂o? □ c₂h₄o₂ □ c₃h₆o₃ □ ch…
A. $C_2H_4O_2$, B. $C_3H_6O_3$, D. $C_5H_{10}O_5$, E. $C_6H_{12}O_6$
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select all the correct answers. a compound has the percent composition …
To solve this, we need to calculate the percent - composition of each given formula and compare with the given percentages. 1. First, find the molar masses of elements: - Molar ma…
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question 25 (1 point) cellobiose is formed from one alpha glucose and o…
D. Two Beta glucose
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select all the correct answers. a compound has the percent composition …
Pd$(O_{2}CCH_{3})_{2}$, $Pd_{2}C_{8}H_{12}O_{8}$
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type the correct answer in the box. tungsten carbide is becoming popula…
94
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question 23 (1 point) which one is not van der walls forces london disp…
C. Hydrophilic
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given 4al + 3o₂ → 2al₂o₃. in this chemical reaction, how many grams of …
708 g
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how many atoms of oxygen are contained in 160 grams of n₂o₅? a. 1.27×10…
D. \(6.28\times 10^{24}\)
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select the correct answer. given sno₂ + 2h₂ → sn + 2h₂o. tin oxide reac…
B. 4.21