Chemie
Chemische Reaktionen, Stöchiometrie, Molekülstrukturen und Elementeigenschaften.
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quiz 8.6be- counting atoms, chemical equations and the law of conservat…
C. iron, oxygen, and hydrogen
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quiz 8.6be- counting atoms, chemical equations and the law of conservat…
$\boldsymbol{\ce{Zn + 2HCl -> ZnCl_{2} + H_{2}}}$ (the first option: Zn + 2HCl → ZnCl₂ + H₂)
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4. you have a buffer system made up of equimolar amounts of carbonic ac…
(a) $\boldsymbol{\ce{HCO3^- + H^+ -> H2CO3}}$ (when HCl is added) (b) $\boldsymbol{\ce{H2CO3 + OH^- -> HCO3^- + H2O}}$ (when NaOH is added)
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a chemist measures the amount of oxygen gas produced during an experime…
2.13
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a chemist determines by measurements that 0.095 moles of iodine solid p…
\(24\) (or more precisely, if we consider 0.095 as two significant figures, the answer is \(24\) g. If we consider 0.095 as having two significant figures, the calculation gives a…
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5) a chemist from a parallel universe, where electrons have a different…
The charge of the electron in this parallel universe is $\boldsymbol{-2.3\times10^{-19}\,C}$ (or $2.3\times10^{-19}\,C$ with a negative sign indicating negative charge).
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a chemist measures the amount of fluorine gas produced during an experi…
\( 0.642 \)
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problem: the density of a pure substance is its mass per unit volume. t…
The first mistake is in the formula for mass: it should be $m = ho V$ (or $m = pV$ using the problem's notation) instead of $m=\frac{V}{p}$. The correct mass calculation is $m = 1…
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show your work... 3.90 x 10²² atoms al \\frac{1\\text{ mole}}{6.02 \\ti…
\(0.0648\) (or approximately \(0.065\) or \(6.48\times 10^{-2}\)) moles Al (the exact rounded answer with three significant figures is \(0.0648\) moles, or if we consider two deci…
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what quantity in moles of csi are in 64.1 grams of csi?
\(0.247\)
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question 3 of 22 determine the quantity of molecules in 2.00 moles of p…
The quantity of molecules in 2.00 moles of \( P_4 \) is \( \boldsymbol{1.20 \times 10^{24}} \) molecules (or approximately \( 1.20 \times 10^{24} \) when using the given options, …
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the contamination that results from a transfer of pathogens from one fo…
A. Cross - contamination
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determine the mass in grams of 2.91 moles of licl
The mass is approximately 123 grams (using 2.91 mol × $\frac{42.39\ \text{g}}{1\ \text{mol}}$ = 123.35 g, which rounds to 123 g).
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what is the empirical formula of a compound that contains only iron and…
A. FeO
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question 2 (10 points) given calculations with the calculator answer, w…
### 1. $23 + 46$ (Wait, the first one is $23 + 46$? Wait, the first problem is $23 + 46$? Wait, the first item: 1. $23 + 46$ (Wait, the user's first problem: "1. 23 + 46 = 69" (Wa…
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presidential retreat adapted from the national parks service catoctin m…
- Many historical events have occurred at the Presidential Retreat: the planning of the Normandy invasion, Eisenhower - Khrushchev meetings, Camp David Accords with Menachem Begin…
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calculate the mass, in grams, of 229.0 atoms of cadmium, cd. one mol of…
\( 4.275\times 10^{-20} \)
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what is the mass percent of water in cobalt(ii) chloride hexahydrate? p…
\( 45.44\% \)
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what is the mass percent of water in cobalt(iii) chloride hexahydrate? …
$39.55$
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determine the mass in grams of 4.93e21 atoms of barium. the mass of one…
1.13 (or ~1.12 - 1.13, depending on precision)
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fill in the blank: a mole is defined as the number of carbon atoms in _…
12
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what is the mass percentage of c in ch₃och₃? provide an answer to two d…
\( 52.14 \)
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how do you find the number of neutrons in an atom? it is also the atomi…
C. Subtract the atomic number from the atomic mass (assuming the orange option is labeled C; if the options are labeled as A: It is also the atomic mass, B: It is also the atomic …
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determine the number of molecules in 38.7 grams of ch₄.
\( \approx 1.45\times10^{24} \) molecules (or more precisely \( \approx 1.452\times10^{24} \) molecules)
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another way the periodic table is arranged is by family. families are d…
B. characteristics
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select the correct answer. read the excerpt. friendship by ralph waldo …
C. Honesty and authenticity are the foundation for true friendships
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a 15.79 g sample of a hydrate of an iron(ii) sulfate compound was heate…
The formula of the hydrate is \( \text{FeSO}_4 \cdot 7\text{H}_2\text{O} \) (Iron(II) sulfate heptahydrate).
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the protons in an atom’s nucleus have what kind of charge?
A. positive
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an atom has 54 protons, 54 electrons, and 131 neutrons. what is the ato…
B. 54
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determine the molar mass of mg(oh)₃. provide an answer to two decimal p…
$58.33\ \text{g/mol}$
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10/20 what makes an atom have a positive charge? more neutrons than ele…
B. more protons than electrons (assuming the purple option is labeled B; if the original labels are different, adjust the label accordingly, but the content is "more protons than …
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calculate the mass, in grams, of 0.695 moles of mn. the mass of one mol…
The mass of \( 0.695 \) moles of Mn is approximately \( 38.18 \) grams.
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an element with an atomic number of 37 and an atomic mass of 85 has how…
48 (corresponding to the orange option with value 48)
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if 8.1e25 molecules of co₂ are produced in a combustion reaction, what …
Approximately 5.9 kg
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to convert from grams to number of molecules, you need to use: answer: …
D. both A and B
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which of the following contains the highest number of atoms? answer: a …
D. All contain an equal number of atoms
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which of the following identifies the number and location of protons in…
D. 16 protons, located in the nucleus (assuming the options are labeled A to D as per the order: Green (A), Purple (B), Orange (C), Cyan (D))
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calculate the number of atoms in 25.0 grams of bromine, br. the mass of…
$\approx 1.88\times10^{23}$ atoms
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calculate the number of atoms of o in 10.0 g of c₂h₆o₂.
\( \approx 1.94\times10^{23} \) atoms
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11. nitrogen trichloride ______ 12. boron monocarbide ______ 13. dinitr…
$BC$ ### 13. dinitrogen trioxide
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use a greek prefix to specify how many atoms of each element exce eleme…
To solve the problem of naming these chemical compounds using Greek prefixes, we follow these steps for each compound: ### 5. $\boldsymbol{N_2O_5}$ ## Step 1: Identify the number …
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which of the following products are toxic? select all that apply. penet…
A. Penetrants, B. Manual transmission fluid, C. Silicone sealants, D. Batteries (all options are toxic)
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long-term exposure to benzene can lead to blood cancer or ______. selec…
B. leukemia
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e) benedict’s reagent is blue in color ______ 4. classify each of the f…
To solve this, we analyze each sample based on the definitions of element, compound, solution (a type of mixture), and mixture: ### a) Sugar and water - A solution is a homogeneou…
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when chemicals are not being used, they should be stored in a ______ ar…
C. cool, dry, dark, and well - ventilated
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determine the quantity of molecules in 2.00 moles of p₄ molecules p₄ st…
The number of molecules of \(P_4\) in 2.00 moles is \(1.20\times10^{24}\) molecules. The setup is \(2.00\ \text{mol}\ P_4\times\frac{6.022\times10^{23}\ \text{molecules}\ P_4}{1\ …
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calculate the mass, in grams, of 3.37e21 atoms of arsenic. the mass of …
0.420 g
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what toxic substance is released when welding stainless steel? select t…
B. hexavalent chromium
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2. determine whether each statement below describes a physical property…
### Question 2 (Physical vs Chemical Property) #### Part a) # Explanation: ## Step1: Recall property types Physical property: observable without chemical change. Color/state are p…
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practice questions-physical and chemical properties 1. identify each of…
To determine if the given answers are correct, we analyze each property: ### 1. Burning wood - **Explanation**: Burning wood involves a chemical reaction (combustion) producing ne…
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model 1 – copper samples group number\tvolume (cm³)\tmass (g)\tsubstanc…
The better - organized table (sorted by Volume in ascending order) is: | Group Number | Volume (\( \text{cm}^3 \)) | Mass (g) | Substance | |--------------|-----------------------…
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isotopes directions: fill in the missing information about the differen…
For Calcium, the number of neutrons is 20, mass number is 40, isotope notation is $^{40}_{20}\text{Ca}$, and isotope name is Calcium - 40. For Iodine, element symbol is I, mass nu…
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what is the energy of an object because of its potential and kinetic en…
D. mechanical energy
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reactant 6co₂ + 6h₂o → c₆h₁₂o₆ + 6o₂ subscript coefficient compound ele…
Carbon (C), Hydrogen (H), Oxygen (O) ### Question 2: How many compounds are on the reactants side of $\boldsymbol{\ce{C2H5OH + 3O2 -> 2CO2 + 3H2O}}$?
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johanna is studying what happens to the energy as a ball rolls down a r…
A. gravitational potential energy
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brianna performed a chemistry experiment in which she divided 1/2 of a …
$\frac{1}{4}$
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read the excerpt from \the author to her book\. \thou ill-form’d offspr…
A, A, C, C
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the sun emits electromagnetic waves at many frequencies, but mostly in …
B. radiant
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shell model explained what is included in the shell model of the atom? …
As the principal energy shell number (\(n\)) increases, the shell contains more subshells (e.g., \(n = 1\) has 1 subshell, \(n = 2\) has 2, \(n = 3\) has 3, etc.). Each subshell h…
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match the term with its definition. isomer choose isotope an alternativ…
- Isomer: Compounds with the same molecular formula but different structural arrangements. - Isotope: an alternative form of the same element (with different neutron number). - Hy…
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isotopes fill in the missing information about the different isotopes o…
To solve problems related to isotopes, we use the following relationships: - Atomic Number (\(Z\)) = Number of Protons (\(p^+\)) = Number of Electrons (\(e^-\)) (in neutral atoms)…
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match the functional group with its property. hydroxyl -oh carbonyl cho…
Determines the two groups of sugar: aldehydes and ketones ### Carboxyl Matching:
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23. how many pm are in 6.7 x 10⁻⁴ nm?
\( 0.67\space pm \) (or \( 6.7\times10^{-1}\space pm \))
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how many significant digits should be reported in the answer to the fol…
1 (Option: 1)
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how many significant digits should be reported in the answer to the fol…
1
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inside stars in space, the nuclei of hydrogen atoms fuse together to fo…
B. nuclear energy (assuming the options are labeled as A: electrical energy, B: nuclear energy, C: chemical energy, D: radiant energy; adjust labels as per original but the correc…
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condensation reaction is a chemical reaction in which ______ molecules …
a. two
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how does the strength of intramolecular bonds within a water molecule c…
c. The intramolecular bonds within a water molecule are stronger than the intermolecular bonds between water molecules.
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why does ice float on liquid water? a hydrogen bonds are absent in ice.…
c. Water expands when it freezes.
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the image displays a chemical structure with carbon (c), hydrogen (h), …
To determine the molecular formula of the compound from its structural formula, we analyze the number of each atom: ### Step 1: Count Carbon (C) atoms Looking at the structure, we…
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what gives water most of its unique properties? a the polarity between …
c. hydrogen bonding between water molecules
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what are hydrogen bonds? a strong bonds between the oxygen atom of one …
c. Weak bonds between the oxygen atom of one water molecule and a hydrogen atom of another.
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in a water molecule, how do the electrical charges compare between oxyg…
c. The oxygen atom is slightly negative in charge, while the hydrogen atoms are slightly positive in charge.
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2. in the space provided, draw the standard whmis symbol for each of th…
- **Compressed Gas**: Draw a cylinder (representing the gas container) with pressure - related lines or a simple gas cylinder graphic. - **Flammable Material**: Draw a flame - lik…
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metric conversion quiz retake prerequisite you must fully complete this…
\(4.30\times 10^{24}\space \text{fg}\)
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extension questions 14. many experiments designed to investigate the re…
Research Question: How does the number of Mentos candies affect the height of the fountain formed when added to Diet Coke? Independent Variable: Number of Mentos candies Dependent…
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11. make the following conversions: (must show work on separate sheet o…
s: a. $\boldsymbol{1.57\ s}$ b. $\boldsymbol{42700\ mL}$ c. $\boldsymbol{2.61 \times 10^{-4}\ mm}$ (or $0.000261\ mm$) d. $\boldsymbol{650\ dm}$ e. $\boldsymbol{0.00642\ kg}$
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ionic compounds form when atoms of two different elements share electro…
FALSE
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positive and negative ions exist in ionic crystals so they are good con…
False
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how do the melting points of ionic compounds compare to water? a very l…
c. very high
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which elements generally form ionic compounds with metals? enter the an…
Non - metals (specifically, elements from groups 15, 16, and 17 of the periodic table, like halogens, oxygen - group elements, and nitrogen - group elements, which are non - metal…
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question 15 6 pts what is the abbreviated electron configuration, and, …
abbreviated electron configuration = \([Ne] 3s^2 3p^4\) and valence electrons = 6 (the last option: "abbreviated electron configuration = [Ne] \(3s^2\) \(3p^4\) and valence electr…
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26. 12h₂o h = 24 o = 12 27. 5n₂o₄ n = ____ o = ____ 28. 3clf cl = ____ …
H = 24, O = 12 ### Problem 27: \(5\ce{N_2O_4}\)
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rank the following orbitals (4p, 2s, 3d, and 3s) in terms of increasing…
(lowest) 2s < 3s < 3d < 4p (highest)
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read this! a well - written research question states the independent an…
What is the effect of the amount of Alka - Seltzer® on the rate of gas production when reacting with Vinegar? ### For "Boiling Points of Alcohols" experiment:
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for the $^{18}$o (oxygen-18) isotope, how many protons, neutrons and el…
8 protons, 10 neutrons, 8 electrons (the last option: 8 protons, 10 neutrons, 8 electrons)
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2. express the answer to each of the following calculations with the co…
$11.55$ ### Part (b)
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which element has a electron configuration of (1s^2 2s^2 2p^6 3s^2 3p^2…
Silicon, Si
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read this! a well - written research question states the independent an…
What is the effect of the amount of Alka - Seltzer® on the rate of gas production when it reacts with vinegar? ### For "Boiling Points of Alcohols" experiment:
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2. express the answer to each of the following calculations with the co…
$11.55$ (Wait, no, wait: 3.42 + 8.132 = 11.552. The number with the least decimal places is 3.42 (2 decimal places). So we round to 2 decimal places. 11.552: the third decimal is …
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in a chemical reaction there are molecules that react and the products …
### Part 1: Label Reactants and Products in the Chemical Equation #### Explanation: In a chemical equation, **reactants** are the substances that undergo the reaction (on the left…
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chemistry review and reflect back to intro page identify which reaction…
Left reaction (reactants → products with energy given out): Exothermic. Right reaction (reactants → products with energy taken in): Endothermic.
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which of the following scenarios represents the best use of a scientifi…
A. predicting weather patterns
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read this! a well - written research question states the independent an…
- **Independent**: Volume of alcohol - **Dependent**: Boiling point of the liquid - **Controlled**: Type of alcohol, atmospheric pressure, type of container, heat source intensity…
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fill in the blank 4 points humans use a synthetic chemical process to c…
Industrial Nitrogen Fixation ### 2. Plant matter in the soil is fossilized, becoming underground coal.
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4. the above atoms are isotopes of the element lithium (li). how many p…
(for a, assuming Li-6): 3, 3, 3 #### Part b: Atom B (Let's assume Li-7)
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12. write a research question, using the format suggested in the read t…
### Question 13: Identifying Variables in Boiling Point Experiment #### Independent Variable: The independent variable is the one that is manipulated or changed in an experiment. …
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it is ok to turn on the gas valves in class without the teacher’s permi…
B. False
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a well - written research question states the independent and dependent…
### Problem 1.3 Analysis: To identify the variables in the experiment where a student wonders if changing the volume of alcohol affects its boiling point, we analyze each type of …
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3. how many significant figures are in each of the underlined numbers? …
1 ### Part b: 47.70 g of copper