Chemistry
Chemical reactions, stoichiometry, molecular structures, and element properties.
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orld history b (15341) defining the dirty war what is the best descript…
a period of repression and human rights abuses committed by military rulers
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silicon (si) is an element that helps computers run. how many valence e…
4
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match each bond with the rearrangement of the valence electrons needed …
ionic bond - transferring of electrons metallic bond - sharing of many electrons covalent bond - sharing of electrons
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how many valence electrons does this oxygen atom have? two four six eig…
six
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which is one use for radioactive isotopes? sanitation architecture mete…
D. archaeology
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fill in the information missing from this table. |nuclide|protons|neutr…
| nuclide | protons | neutrons | $Z$ | $A$ | | ---- | ---- | ---- | ---- | ---- | | $^{27}_{13}Al$ | 13 | 14 | 13 | 27 | | $^{191}_{77}Ir$ | 77 | 114 | 77 | 191 | | $^{169}_{69}Tm…
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the curies took pure uranium and a uranium - containing substance. when…
There are more radioactive substances than uranium.
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carbon-14 is used to determine the time an organism was living. the amo…
11,460 years
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fill in the information missing from this table. |nuclide|protons|neutr…
| nuclide | protons | neutrons | \(Z\) | \(A\) | | ---- | ---- | ---- | ---- | ---- | | \(_{31}^{71}\text{Ga}\) | 31 | 40 | 31 | 71 | | \(_{24}^{53}\text{Cr}\) | 24 | 29 | 24 | 53…
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carbon-14 is the typical radioisotope used to date materials; however, …
uranium - 238
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elemental carbon has 6 protons and 6 neutrons. this is often described …
C. 150 neutrons
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juliet started working with a radioactive substance. in 1997, she start…
cobalt-60
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in the table below, there are descriptions of an experiment on samples …
1. (can't decide) 2. metal 3. nonmetal
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in the table below, there are descriptions of an experiment on samples …
1. nonmetal 2. metal 3. nonmetal
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write a complete chemical formula, including physical state symbol, for…
helium: $He(g)$ lanthanum: $La(s)$ hydrogen: $H_2(g)$
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which statements best describe half - lives of radioactive isotopes? ch…
The half - life varies depending on the isotope. Half - lives range from fractions of a second to billions of years. The half - life of a particular isotope is constant.
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write a complete chemical formula, including physical state symbol, for…
phosphorus: $P_4(s)$ neodymium: $Nd(s)$ chlorine: $Cl_2(g)$
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write a complete chemical formula, including physical state symbol, for…
| element | formula | | ---- | ---- | | iron | Fe(s) | | neon | Ne(g) | | nitrogen | N₂(g) | | carbon | C(graphite, s) |
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write the chemical symbols for three different atomic cations that all …
$Na^+$, $Na^{2+}$, $Na^{3+}$
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write the chemical symbols for three different atomic anions that all h…
$C^{2 - }$, $C^{3 - }$, $C^{4 - }$
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write the chemical symbols for three different atomic cations that all …
$Al^{1 +}$, $Al^{2+}$, $Al^{3+}$
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question: 4 of 20 chemical weapons are toxic chemicals contained in a d…
All of the above.
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identify how scientists use radioactive isotopes by selecting the best …
Archaeologists use radioactive isotopes to: Determine the age of artifacts (by radiocarbon - dating). Scientists use radioactive isotopes in agriculture to: Study plant processes …
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multiple - choice question what is the difference between a linear shap…
The lone - electron pair; The bond angle
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classify each of the molecules below. ch₃ - ch - ch₂ - ch₂ - oh ch₃ - c…
First molecule: primary alcohol Second molecule: tertiary alcohol Third molecule: tertiary alcohol
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incorrect your answer is wrong. please read the explanation for more he…
First molecule: secondary alcohol Second molecule: secondary alcohol Third molecule: primary alcohol
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use the references to access important values if needed for this questi…
a. $2.80\times 10^{22}$ atoms b. $8.44$ g
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for the following reaction, 4.67 grams of bromine are mixed with excess…
The theoretical yield of bromine monochloride is $6.74$ grams and the percent yield is $79.7\%$.
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for the following reaction, 3.59 grams of tetraphosphorus decaoxide are…
The theoretical yield of phosphoric acid is approximately $4.98$ grams and the percent yield is approximately $92.2\%$
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for the following reaction, 31.1 grams of bromine are allowed to react …
The formula for the limiting reactant is $Cl_2$. The maximum mass of bromine monochloride that can be formed is approximately $39.4\ g$. The mass of the excess reactant ($Br_2$) r…
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according to the following reaction, how many grams of ammonium nitrite…
46.2 g
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according to the following reaction, how many grams of phosphoric acid …
$31.5$
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7. without the _, our french fries wouldnt taste as good! maillard reac…
C. Maillard Reaction
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when the following molecular equation is balanced using the smallest po…
The coefficients are 12, 1, 4, 6.
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6. the chemical reaction called ____ led to the creation of soap. photo…
saponification
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5. answer the question regarding the following chemical reaction: 2h₂ +…
4
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answer the question regarding the following chemical reaction: 2h₂ + o₂…
the number of atoms in the formation of that molecule
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3. answer the question regarding the following chemical reaction: 2h₂ +…
coefficient
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2. answer the question regarding the following chemical reaction: 2h₂ +…
Oxygen
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answer the question regarding the following chemical reaction: 2h₂ + o₂…
Hydrogen
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5. the chemical reaction called fermentation led to the development of …
A. soda, B. yogurt
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3. saponification led to mixing of water and animal fats and the develo…
B. soap
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the balanced chemical equation for the reaction between perchloric acid…
12 moles of perchloric acid react with 1 mole of tetraphosphorus decaoxide to produce 4 moles of phosphoric acid and 6 moles of dichlorine heptaoxide. So the answers are 4 moles o…
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1. what chemical reaction allowed for humans to cook food at high tempe…
D. Maillard reaction
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consider the following unbalanced particulate representation of a chemi…
$P_4+6F_2 ightarrow4PF_3$
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5. true or false: there are more hydrogen atoms in the product than in …
False
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3. answer the following question in regards to the chemical equation be…
2
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answer the following question in regards to the chemical equation below…
\(2H_2O\)
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1. answer the following question in regards to the chemical equation be…
$2H_2$ and $O_2$
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5. when water is changed into hydrogen gas and oxygen gas, what happens…
The weight of the gases is the same as the water.
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4. the image below shows the reactants in a chemical equation. how many…
10
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in the reaction, for every molecule of propane, how many molecules of o…
5
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2. according to the law of conservation of mass, if you start a chemica…
100 grams
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1. which statement best describes what happens when a nail rusts? it sh…
It undergoes a chemical change where a new substance is formed.
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5. the number placed in front of a chemical symbol or formula that show…
coefficient
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4. the chemicals that enter into a chemical reaction are called the pro…
reactants
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2. a mathematical statement that represents the product creation from r…
A. chemical equation
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3. the result of substances being combined in a chemical reaction is ca…
product
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1. a process in which one or more substances are changed into others is…
C. chemical reaction
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question 1 what is one specific question about space that could be best…
One specific question for robotic space exploration: What is the chemical composition of Venus' surface? Use: Exploring inhospitable planets. Advantage: No risk to human life. One…
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3. what does the arrow in a chemical equation show? the type of substan…
the direction of the reaction
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2. in a chemical equation, the ____ are on the left, and the ____ are o…
reactants, products
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1. a chemical equation has what general form? molecule -> atom reactant…
B. Reactants → Products
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5. balance the following chemical equation and choose the correct answe…
D. \(2Al+3Cl_2 ightarrow 2AlCl_3\)
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4. balance the following chemical equation and choose the correct answe…
$C + O_2 ightarrow CO_2$ (the given equation is already balanced, and this is the correct form among the options which is not explicitly stated in the options but is the base - co…
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3. balance the following chemical equation and choose the correct answe…
$N_2 + 3H_2 ightarrow2NH_3$ (the correct option among the ones shown in the image is the one with this equation)
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1. balance the following chemical equation and choose the correct answe…
$2Mg + O_2 ightarrow 2MgO$
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1. balance the following chemical equation and choose the correct answe…
$2H_2 + O_2 ightarrow 2H_2O$ (the fourth option)
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8. rotting banana: physical change chemical reaction
Chemical reaction
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7. toasting bread: o chemical reaction o physical change
Chemical reaction
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6. chopping wood: physical change chemical reaction
Physical change
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5 mixing vinegar and baking soda: o chemical reaction o physical change
Chemical reaction
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4. shredding paper: o physical change o chemical reaction
Physical change
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3. fireworks: o physical change o chemical reaction
Chemical reaction
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2 wood burning: physical change chemical reaction
Chemical reaction
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1. ice melting: chemical reaction physical change
Physical change
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when 5.682 grams of a hydrocarbon, cxhy, were burned in a combustion an…
empirical formula = $CH_2$ molecular formula = $C_2H_4$
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5. when water evaporates from a glass, this is an example of a: physica…
D. physical change
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3. a new substance that is created from a chemical reaction is called t…
product
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when 3.478 grams of a hydrocarbon, cxhy, were burned in a combustion an…
empirical formula = $C_2H_3$ molecular formula = $C_2H_3$
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2. the process by which a chemical change occurs is called a: chemical …
chemical reaction
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1. a change that does not form a new substance is called a(n): physical…
D. physical change
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8. digesting food is an example of: physical change chemical change
Chemical change
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7. dissolving salt in water is an example of: physical change chemical …
Physical change
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6. melting ice is an example of: - physical change - chemical change
Physical change
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5. breaking glass is an example of: physical change chemical change
Physical change
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4. milk going sour is an example of physical change chemical change
Chemical change
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chemical change physical change burning wood is an example:
Chemical change
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1. baking a cake is an example of: physical change chemical change
Chemical change
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under certain conditions, the substances sulfur dioxide and oxygen comb…
32.5 g
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under certain conditions, the substance ammonium nitrate can be broken …
10.26 grams
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5. henry was investigating physical and chemical changes in matter. whi…
rusting of iron
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4. what change makes a new material? crushing ice cubes cooking eggs on…
cooking eggs on a stove
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a compound is found to contain 7.522 % phosphorus and 92.47 % iodine by…
$PI_{3}$
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3. a student kept a notebook during an investigation. which recorded ob…
The color of two mixed solutions changed from clear to white., Two solutions were mixed and the resulting solution felt hot.
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2. chemical change can be identified by specific observations. which wo…
A light green powder forms on the outside of a penny.
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1. when a scientist performs an experiment, there are many changes that…
The substance changed into a new substance.
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5. when chemicals combine to cause a new substance to form this is call…
D. chemical change
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4. a change in a state of matter where no new substance is formed is ca…
D. physical change
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3. substances that are combined to form products in a chemical reaction…
reactants