Química
Reacciones químicas, estequiometría, estructuras moleculares y propiedades.
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multiple-choice question a negatively charged atom is the result of ...…
more electrons than protons
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if you know the mass # and the # of protons, how can you calculate the …
take the mass number and subtract the number of protons
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what do you use to determine which element you are working with? □ char…
atomic #
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4. why may color change be an example of a chemical change?
A color change may indicate that new substances with different chemical properties have formed, which is the defining characteristic of a chemical change.
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practice: mixed mole conversions (2-step) what is the mass of 8.07 x 10…
The mass of $8.07\times 10^{24}$ molecules of $O_2$ is $\boldsymbol{428.94\ \text{g}}$ (or we can also see from the given options, the calculation matches with $428.94\ \text{g}\ …
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icp chapter 2.2 vocabulary review (24pts) pretty simple. use my chapter…
### Physical property - **Definition**: A characteristic of a substance observable/measurable without changing its chemical identity (e.g., color, density, melting point). - **Exa…
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25. why is a hydrogen molecule (h₂) more stable than two separate hydro…
A hydrogen molecule ($\ce{H_2}$) is more stable because the two H atoms share electrons to form a covalent bond, giving each atom a stable electron configuration (duet of electron…
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the diagrams below show the structures of two ionic solids, sro and the…
A. \( \text{Mg}^{2+} \)
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the energy required to separate the ions in a nacl crystal lattice into…
A. $\ce{Na^{+}}$ has a smaller ionic radius than $\ce{Rb^{+}}$, so the distance between cation and anion is shorter in $\ce{NaCl}$ than in $\ce{RbCl}$.
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the triple point of most substances is a. always measured when a substa…
C. Less than atmospheric pressure
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the triple point of a substance is a. the point at which the substance …
D. The point where a substance can exist as a solid, liquid, or vapor at the same time at one specific pressure and temperature
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the pressure and temperature at which there is no longer a difference b…
C. Critical point.
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copper-nickel alloys are highly durable, resistant to corrosion, and ea…
A. The diagram with 15 white (copper) circles and 5 gray (nickel) circles (ratio 3:1)
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what is a practical use for knowing a substances triple point? a. tripl…
B. Calibrating thermometers using the triple point temperature
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which of the following is accurate about gases? a. gases are not fluid …
C. A gas must be contained in a closed container or it will escape into the atmosphere
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a characteristic of water vapor, but not other states of water, is a. w…
B. Water vapor is compressible
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a. writing chemical formulas of ionic compounds set ii directions: writ…
### A. Writing Chemical Formulas 1. $K_2S$ 2. $Be_3N_2$ 3. $H_2SO_3$ 4. $Mg(OH)_2$ ### B. Naming Ionic Compounds 1. Sodium sulfide 2. Calcium phosphate 3. Lithium nitride 4. Hydro…
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the three states of matter represent a. the amount of work a material c…
D. Diverse levels of molecular energy within a material or substance
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size, form, shape, and state relates to a. the critical point of matter…
D. The physical state of matter
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the energy change that takes place when the atoms of materials are rear…
C. Chemical energy
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how would the law of conservation of matter explain what happens to a c…
D. The liquid water is now water vapor of the same quantity
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practice: mixed mole conversions (2-step) how many moles of water (h₂o)…
\(\boldsymbol{0.94\space mol\space H_2O}\) (corresponding to the option: \(\boldsymbol{\square\ 0.94\space mol\ H_2O}\))
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according to the law of conservation, when matter changes state its ___…
B. mass
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what is the relationship between atoms and molecules? a. molecules are …
A. Molecules are made up of atoms
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identifying an isotope an isotope of the element fluorine has 9 protons…
fluorine-19
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determing an isotope use the drop - down menus to complete the statemen…
An isotope has the same number of **protons** but a different number of **neutrons** than other atoms of the same element.
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which of the following steps is required before bacteria can break down…
Water is placed in an aeration basin to increase oxygen
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identifying atomic number the element copper has 29 protons. what is th…
29
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1. the diagram above shows the repeating groups of atoms that make up t…
a. The properties will likely be different because the repeating groups of atoms that make up the samples are different.
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describing chemical symbols which statement accurately describes the ch…
B. The chemical symbol always begins with a capital letter.
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3. tiana is a chemist who is making a chemical to add to swimming pools…
c. Diagram C
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describing elements use the drop - down menu to complete the sentence. …
compound
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5. banana mixed two substances together. it first smells like flowers a…
B. Diagram B
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periodic table of the elements e h d b c g f a (1 pt each) match the qu…
1. 1 - A 2. 2 - B 3. 3 - H 4. 4 - C 5. 5 - I 6. 6 - E 7. 7 - I 8. 8 - E 9. 9 - I 10. 10 - H 11. 11 - A 12. 12 - F 13. 13 - F 14. 14 - B 15. 15 - H
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it is composed of nitrogen. it is composed of oxygen. it is composed of…
It is composed of a mixture of gases.
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identifying ions what ion is formed when an atom of mercury (hg) loses …
$\boldsymbol{Hg^{+2}}$ (Option: $\boldsymbol{Hg^{+2}}$)
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instructions: show all work and include units in every step. 1. how man…
1. $1.00\ \text{mol}$ 2. $1.00\ \text{mol}$ 3. $1.00\ \text{mol}$ 4. $1.00\ \text{mol}$ 5. $12.8\ \text{g}$ 6. $139\ \text{g}$ 7. $88.0\ \text{g}$ 8. $71.0\ \text{g}$
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describing isotopes what is the mass number of the isotope lithium - 7?…
Mass number of lithium-7: $7$ Number of neutrons in lithium-8: $5$
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select the correct answer. why might two elements possess similar chemi…
A. They belong to the same group of the periodic table.
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co₂(g) + 2so₂(g) → 3o₂(g) + cs₂(g) considering the thermodynamic data g…
C. Favorable at high T
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formation of glucose balanced equation most chemical reactions are cons…
B. \(6CO_2(g)+6H_2O(g) ightarrow C_6H_{12}O_6(g)+6O_2(g)\)
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directions: complete the chart below. | element | number of valence ele…
| Element | Number of Valence Electrons | # of electrons gained or lost to fill outer energy level | Charge (Oxidation Number) | |---------------|------------------------------|--…
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which of the following compounds would be most likely to decompose into…
$\ce{N2H4(l)}$, $\Delta G^\circ\text{f}= + 149.34\ \text{kJ/mol}$
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which statement is true for the reaction below? $2\\ce{o_3}(g) \ ightar…
The reaction will occur at all temperatures.
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calculate the change in entropy of liquid bromine using the data below.…
+152
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calculate the change in entropy for the reaction. sicl₄(l) + 2h₂o(l) → …
\(-154\)
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in which example is the entropy of the final state greater than the ent…
Dry ice (solid \( \text{CO}_2 \)) sublimes.
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12. what is the difference between an atom and an element? 13. why is t…
An atom is the smallest particle of matter that retains the chemical properties of an element. An element is a pure substance made up of only one type of atom (all atoms of an ele…
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which substance will have the greatest standard molar entropy value? h₂…
Rn(g)
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1. diagram sodium has 11 protons and 11 neutrons in its nucleus. draw a…
Draw a central nucleus (label: 11 protons, 11 neutrons). Draw three energy levels (circles) around it. First level: 2 electrons, second: 8 electrons, third: 1 electron. Label each…
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calculate the enthalpy of vaporization, the energy required to convert …
+44
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calculate the standard reaction enthalpy for the reaction between clf₃ …
+480.2
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which of the reactions below is a formation reaction? ½n₂(g) + ³⁄₂h₂(g)…
$\boldsymbol{\frac{1}{2}\text{N}_2(\text{g}) + \frac{3}{2}\text{H}_2(\text{g}) ightarrow \text{NH}_3(\text{g})}$ (the first option)
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which of the reactions below is a formation reaction? h₂(g) + ½cl₂(g) →…
$\boldsymbol{\ce{H2(g) + 1/2Cl2(g) -> HCl(g)}}$ (the first option: $\ce{H2(g) + 1/2Cl2(g) -> HCl(g)}$)
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calculate the enthalpy for this reaction. \\ce{ch3cl + o2 -> co + hcl +…
\(-404\)
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calculate the enthalpy for this reaction. 2hg + cl₂ → hg₂cl₂ use the fo…
\(-265\)
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143 kj of energy was released during the reaction, raising the temperat…
\( \approx 2.79 \)
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the combustion of 3.00 grams of octane, c₈h₁₈, in a bomb calorimeter re…
\(-143\) (or more precisely \(-143.4\) depending on sig fig interpretation, but 3.00 has 3 sig figs, so \(-143\) or \(-143.4\) if considering more decimals)
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0.50 g of mg reacts with excess oxygen in a bomb calorimeter. the overa…
-590 (or -592, depending on significant figures calculation; but following the steps, the precise calculation gives approximately -591.7, which rounds to -590 or -592 based on sig…
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2naoh + h₂so₄ → 2h₂o + na₂so₄ 50.0 ml of 0.50 m h₂so₄ is added to 60.0 …
-24.3 kJ/mol (or more precise -24.33 kJ/mol, depending on rounding)
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understand main ideas 1. diagram sodium has 11 protons and 11 neutrons …
The number of neutrons in beryllium - 9 is 5. The calculation is done using the formula for atomic mass ($A=p + n$), where $A = 9$ (atomic mass of beryllium - 9) and $p = 4$ (numb…
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select the correct answer? the ph scale measures the acidity of a liqui…
A. 0.001
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2naoh + h₂so₄ → 2h₂o + na₂so₄50.0 ml of 0.50 m h₂so₄ is added to 60.0 m…
\(-580\) (or more precisely \(-579.96\))
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2naoh + h₂so₄ → 2h₂o + na₂so₄ 50.0 ml of 0.50 m h₂so₄ is added to 60.0 …
\(115.5\)
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11. $c_6h_{12}o_6 + o_2 \ ightarrow co_2 + h_2o$ 12. $al + o_2 \ ightar…
11. $\mathrm{C_6H_{12}O_6 + 6O_2 ightarrow 6CO_2 + 6H_2O}$ 12. $\mathrm{4Al + 3O_2 ightarrow 2Al_2O_3}$ 13. $\mathrm{2NaOH + H_2SO_4 ightarrow Na_2SO_4 + 2H_2O}$ 14. $\mathrm{2C_8…
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hcl + naoh → nacl + h₂o 25.0 ml of 1.00 m hcl is added to 75.0 ml of 1.…
0.0250
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hcl + naoh → nacl + h₂o 25.0 ml of 1.00 m hcl is added to 75.0 ml of 1.…
\(-3706\) (or \(-3705.66\))
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types of chemical reactions balance each of the following reactions. th…
1. (Already balanced) synthesis 2. $2H_2O ightarrow 2H_2 + O_2$; decomposition 3. (Already balanced) single replacement 4. $2CO + O_2 ightarrow 2CO_2$; synthesis 5. $2HgO ightarro…
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hcl + naoh → nacl + h₂o 25.0 ml of 1.00 m hcl is added to 75.0 ml of 1.…
102
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the heat of solution, $q_{soln}$, is +27 j for the dissolution of a sol…
The water temperature decreases as the endothermic dissolution absorbs heat from the water.
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the water absorbs about 2120 j and the calorimeter absorbs about 22 j. …
\(-2142\)
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a 25.5 g piece of metal with a temperature of 105.00 °c is dropped into…
\(+21.7\)
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chapter 4: parts of the atom & bonding guided reading - short answer 1.…
The three particles that make up an atom are protons, neutrons, and electrons. Protons and neutrons are located in the nucleus (the central part) of the atom, while electrons are …
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type the correct answer in the box. calculate the density of the substa…
3.9
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select the correct answer from each drop - down menu. mendeleev’s table…
the atomic numbers of the elements
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select the correct answer from each drop - down menu. mendeleevs table …
it could accommodate new elements
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the final temperature at equilibrium is 25.00 °c. the heat is supplied …
\( \boldsymbol{102.5} \) (or more precisely \( 102.47 \)) \(^{\circ}C\) (depending on the required precision, the calculation gives approximately \( 102.5^{\circ}C \) when rounded…
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a 50.0 g piece of granite was immersed in 28.3 g of water. the water an…
+2957 J (or more precisely +2957.35 J, depending on significant figures)
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elements of each group in the periodic table have certain characteristi…
- "very reactive nonmetals" → halogens - "don't react naturally with other elements" → noble gases - "solids at room temperature" → alkali metals
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drag each tile to the correct location. classify each property as inten…
- Intensive Property (Propiedad Intensiva): reactivity with acid - Extensive Property (Propiedad Extensiva): volume, length
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you decide to use aluminum \ice cubes\ to cool your juice. what is the …
-15,000 J
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what is the energy change for the thermite reaction when 11.0 g al reac…
-173 kJ (corresponding to the option: -173 kJ)
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8. which is a general characteristic of metals? a. poor conductors of h…
8. C. Good conductors of electricity 9. B. Metals from nonmetals 10. D. Valence electrons 11. A. Dalton 12. B. Covalent bond 13. C. Nonmetals 14. C. Protons and neutrons
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which thermochemical equation corresponds to the graph? energy diagram …
B. \( \text{A} + 2\text{B} ightarrow \text{AB}_2 + \text{Energy} \) (assuming the middle option is B, as per typical multiple - choice layout with the second option being the corr…
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elements and the periodic table assessment 1. what is the center of an …
1. B. Nucleus 2. C. Proton 3. D. Chadwick 4. A. Protons 5. B. In the energy levels surrounding the nucleus 6. C. Plum pudding model 7. C. Similar chemical properties
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which of the following is not an observable or measurable outcome for a…
The temperature of the water in the beaker goes down.
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two systems, one with 50.0 g of aluminum and the other 100.0 g of alumi…
The heat added is greater for the 100.0 g Al system. (Corresponding option: The heat added is greater for the 100.0 g Al system.)
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select the correct answer. which statement best describes how a compoun…
A. A compound contains two or more elements in a fixed proportion
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hematite is a naturally occurring mineral and a common form of iron ore…
B. The hematite particles rearrange to form a new substance.
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select the correct answer. which statement describes both homogeneous m…
C. Their components can be separated by physical processes.
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7. can two elements be used as reactants for a synthesis reactions? if …
Yes. Example: \( \ce{2H_2 + O_2 -> 2H_2O} \) (hydrogen and oxygen, elements, synthesize water). ### Question 8
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select the correct location. which part of the periodic table would con…
The light - blue colored block (the bottom block in the diagram, representing inner transition metals: lanthanides and actinides)
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select the correct answer. a chemist divides a large sample of a mixtur…
C. heterogeneous mixture
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0 p₄ + 0 f₂ → 0 pf₃
Left box: $1$ $\text{P}_4$ + $6$ $\text{F}_2$ Right box: $4$ $\text{PF}_3$ Balanced equation: $\text{P}_4 + 6\text{F}_2 ightarrow 4\text{PF}_3$
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0 so₃ → 0 so₂ + 0 o₂
$2\text{SO}_3 ightarrow 2\text{SO}_2 + \text{O}_2$
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type the correct answer in the box. round your answer to the nearest hu…
63.55
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0 pcl₃ → 0 p₄ + 0 cl₂
Left box: $4\text{PCl}_3$ Right box: $\text{P}_4 + 6\text{Cl}_2$
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2 n₂ + 0 o₂ → 2 n₂o not balanced
The balanced chemical equation is $\boldsymbol{2\text{N}_2 + \text{O}_2 = 2\text{N}_2\text{O}}$
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× not balanced try again hide why 1 n₂ + 3 o₂ → 5 n₂o
The balanced chemical equation is $\boldsymbol{2N_2 + O_2 ightarrow 2N_2O}$
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select the correct answer. bromine (br) belongs to the halogen family. …
D. 7