Answers
Galaxies are formed from the gravitational pull of massive objects in space. Some galaxies from around super massive black holes (spiral) or a group or collection or cluster of stars.
Answer:
Both are formed by gravitational forces.
Explanation:
I took the test!!
Related Questions
Write the complete ionic equation and the Net ionic equation for: K2C2O4(aq)+Pb(OH)2(aq) -> 2KOH(aq)+PbC2O4(s)
Answers
K₂C₂O₄(aq)+Pb(OH)₂(aq) → 2KOH(aq) + PbC₂O₄(s).
Ionic equation:
2K⁺(aq) + C₂O₄²⁻(aq) + Pb²⁺(aq) + 2OH⁻(aq) → 2K⁺(aq) +2OH⁻(aq)+PbC₂O₄(s)
Net ionic eqation:
C₂O₄²⁻(aq) + Pb²⁺(aq) → PbC₂O₄(s).
s is solid, do not dissolve in water, potassiom hydroxide is trong base and dissolves in water.
The complete ionic equation for the reaction of K2C2O4(aq) with Pb(OH)2(aq) includes all ions present. The net ionic equation simplifies to Pb2+(aq) + C2O42-(aq) → PbC2O4(s).
When solutions of potassium oxalate (K2C2O4) and lead(II) hydroxide (Pb(OH)2) are mixed, a double displacement reaction occurs, forming potassium hydroxide (KOH) and lead(II) oxalate (PbC2O4), where lead(II) oxalate is an insoluble precipitate.
The complete ionic equation for the reaction is:
2 K+ (aq) + C2O42- (aq) + Pb2+ (aq) + 2 OH- (aq) → 2 K+ (aq) + 2 OH- (aq) + PbC2O4 (s)
By cancelling out the spectator ions, we can write the net ionic equation:
Pb2+ (aq) + C2O42- (aq) + 2 OH- (aq) → PbC2O4 (s) + 2 OH- (aq)
However, we can cancel out the common ions further to simplify:
Pb2+ (aq) + C2O42- (aq) → PbC2O4 (s)
If the atmospheric pressure is 0.975 atm what is the pressure of the enclosed gas
Answers
The pressure of the enclosed gas is likely equivalent to the given atmospheric pressure, so in this scenario, it would be 0.975 atm.
Explanation:
The pressure of the enclosed gas in this scenario would be equivalent to the given atmospheric pressure, in this case being 0.975 atm. Atmospheric pressure is defined by the sum of all the partial pressures of the atmospheric gases added together. In a closed system, typically if no other factors are impacting the system, the pressure of a gas would be equal to the atmospheric pressure. More precise measurement might require the consideration of factors like temperature and volume as per the ideal gas law, but with the information provided, the pressure of the enclosed gas can be assumed to be the same as the atmospheric pressure which is 0.975 atm in this case.
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The pressure of an enclosed gas can differ from atmospheric pressure based on factors like volume, temperature and amount of gas. In the absence of these variables, we assume equality with atmospheric pressure. For the given atmospheric pressure of 0.975 atm, the assumed pressure of the enclosed gas is also 0.975 atm.
Explanation:
The question refers to understanding the pressure of an enclosed gas when the atmospheric pressure is 0.975 atm. The pressure of a gas enclosed within a closed system might not necessarily be the same as the atmospheric pressure, as it depends on several factors such as the volume of the gas, the temperature, and the number of gas molecules present.
Without additional information, we must assume that the pressure inside is equal to the atmospheric pressure according to the principles of equilibrium. So, if the atmospheric pressure is 0.975 atm, then the pressure of the enclosed gas should be assumed to be also 0.975 atm, unless stated otherwise. This is the same principle as the pressure inside and outside of a properly inflated tyre, or the pressure inside an unopened soda can and the atmospheric pressure.
If this is a manometer style problem where there is an additional pressure from a column of fluid (like mercury), we would need the height of the column to calculate the additional pressure exerted by the gas. For most homework problems, the system is at equilibrium and the pressure inside the container is the same as outside.
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What is the correct formula for the compound formed between sodium and iodine based on their positions in the periodic table?
Answers
Because the charges on anion and cation are the same; the molecular formula will be NaI
The compound formed from sodium and iodine, based on their positions on the periodic table, is Sodium Iodide (NaI). Sodium and Iodine combine in a 1:1 ratio, as Sodium is a metal with a +1 charge and Iodine is a non-metal with a -1 charge.
Explanation:The compound formed between sodium and iodine based on their positions in the periodic table is Sodium Iodide. In the periodic table, sodium is a metal (from Group 1: alkali metals) and iodine is a non-metal (from Group 17: halogens). When a metal and a non-metal combine, they typically form ionic compounds. Sodium, with a charge of +1, and iodine, with a charge of -1, combine in a 1:1 ratio to form Sodium Iodide, which has the chemical formula NaI.
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A 14.01 g sample of n2 reacts with 3.02 g of h2 to form ammonia (nh3). if ammonia is the only product, what mass of ammonia is formed? 17.01 g 1.10 g 14.01 g 3.02 g 23.07 g
Answers
Chemical reaction: 3H₂ + N₂ → 2NH₃.
m(N₂) = 14,01 g.
n(N₂) = m(N₂) ÷ M(N₂).
n(N₂) = 14,01 g ÷ 28,02.
n(N₂) = 0,5 mol.
m(H₂) = 3,02 g.
n(H₂) = 3,02 g ÷ 2,01 g/mol.
n(H₂) = 1,5 mol.
From chemical reaction: n(N₂) : n(H₂) = 1 : 3.
From chemical reaction: n(N₂) : n(NH₃) = 1 : 2.
n(NH₃) = 2 · 0,5 mol = 1 mol.
m(NH₃) = 1 mol · 17 g/mol.
m(NH₃) = 17 g.
Final answer:
The mass of ammonia formed when 14.01 g of N2 reacts with 3.02 g of H2 is the sum of the reactant masses, which equals 17.03 g of NH3.
Explanation:
The question involves a chemical reaction where nitrogen gas (N2) reacts with hydrogen gas (H2) to form ammonia (NH3). The balanced equation for the formation of ammonia is:
N2(g) + 3H2(g) → 2NH3(g).
In the scenario provided, 14.01 g of N2 reacts with 3.02 g of H2. Given the stoichiometry of the reaction and the law of conservation of mass, the mass of the reactants equals the mass of the product. Therefore, if you start with 14.01 g of N2 and 3.02 g of H2, the mass of ammonia formed would be the sum of the masses of nitrogen and hydrogen, which is 17.03 g NH3.
20 points
Choose all the answers that apply. Which of the following is an example of an ion?
Na+
Cl-
Ar
F+
Answers
na+ cl- and f+ is the answer
What is the concentration of x2??? in a 0.150 m solution of the diprotic acid h2x? for h2x, ka1=4.5??10???6 and ka2=1.2??10???11?
Answers
The concentration of X2 in a 0.150 M solution of the diprotic acid H2X is calculated by using equilibrium constants Ka1 and Ka2, which are specific to each step in the ionization process. This involves solving for the concentration of HX- first, and then X2-. The assumption that the change in concentration (x) is negligible compared to initial concentrations is valid if x is less than 5%.
Explanation:The concentration of X2 in a 0.150 M solution of the diprotic acid H2X can be calculated using the given equilibrium constants Ka1 and Ka2. It is important to remember that diprotic acids undergo ionization in two steps and each step has its own equilibrium constant.
Ka1 = 4.5×10-6 is the equilibrium constant for the first dissociation and Ka2 = 1.2×10-11 is for the second.
In the first step, H2X dissociates into HX- and H+. From the value of Ka1 and the initial concentration of H2X, one can solve for the concentration of HX-. The next step is the dissociation of HX- into X2- and H+. Similarly, by using Ka2 and the concentration of HX-, the concentration of X2- can be calculated. The calculation usually assumes that x is small compared to initial concentrations and this assumption is valid if the concentration of x is less than 5% of initial concentrations.
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Magnesium hydroxide (Mg(OH)2): g/mol
Answers
To determine the molar mass, you need to get the atomic mass of the molecule. To do this, check the periodic table for the atomic mass or average atomic weight of each element.
Mg = 24.305 x 1 = 24.305 amu
O = 15.9994 x 2 =31.9988 amu
H = 1.0079 x 2 = 2.0158 amu
Then, add all the components to get the atomic mass of the molecule.
24.305 amu + 31.9988 amu + 2.0158 amu = 58.3196 amu
The atomic mass is just equivalent to its molar mass.
So, the molar mass of Magnesium hydroxide (Mg(OH)2) is 58.3196 g/mol.
molar mass of Mg(OH)2 = 58.305 grams/mole
Explanation:
From the periodic table:
atomic mass of Mg = 24.305 grams
atomic mass of oxygen = 16 grams
atomic mass of hydrogen = 1 gram
Now the given compound has:
1 mole of Mg, 2 moles of oxygen and 2 moles of hydrogen
Therefore:
molar mass of Mg(OH)2 = 24.305 + 2(16) + 2(1) = 58.305 grams/mole
Which of these is an element?
A. Oxygen
B. Sodium Chloride
C. Water
D. Air
Answers
An "element" is a substance that is made entirely of one type of atom. Out of the four given options, A. Oxygen is considered an element, because it just can't be broken down farther. As for the other options, Sodium Chloride and water are both compounds, not elements. Air is a mixture.
Lewis structure for SiOS
Answers
with Si as the central atom
Number of valence electrons around each of the atoms
Si - 4
S - 6
O - 6
total number of valence electrons - 16
the number of lone pairs - 16/2 = 8
1 pair is shared between O and Si and 1 pair shared between Si and S
8-2 = 6 pairs are remaining
if we add 3 pairs each to O and Si as lone pairs their octets are complete however Si has an incomplete octet
then we convert the single bond between to O and Si to a double bond and bond between Si and S also to a double bond. By doing so the number of lone pairs around S and O are reduced to 2 lone pairs
. . . .
: O = Si = S :
Here we go!
Explanation:
what is the number of electrons shared between the atoms in I2 molecule (That is an i not a 1)
1) 7
2) 2
3) 8
4) 4
Answers
Iodine has seven valence electrons. Using valence shell electron pair repulsion (VSEPR) theory, we can predict the Lewis dot structure for [tex]I_2[/tex]. We see there are fourteen electrons, and we can make a covalent bond, leaving three lone pairs on each atom. The bond replaces two electrons, so the number of electrons shared is two.
I2, or iodine, is a diatomic molecule held together by a single covalent bond. In this bond, two electrons are shared. Therefore, the answer is 2.
Explanation:The molecule of I2, or iodine, is a diatomic molecule; that is, a molecule consisting of two iodine atoms. This molecule is held together by a single covalent bond. Covalent bonds are formed when atoms share electrons. In a single covalent bond, two electrons are shared - one from each atom involved. Therefore, in an I2 molecule, the number of electrons shared between the atoms is 2.
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When the same force is applied. Which wagon will accelerate faster
Answers
However, I'll tell you how to solve it and you can apply on the given numbers.
We have:
F = m * a
where:
F is the force
m is the mass
a is the acceleration
From this formula, we can note that at constant force, the mass of the body is inversely proportional to its acceleration. This means that as the mass decreases, the acceleration increases and vice versa.
Now, applying this concept to the given problem, we will find that:
The force applied is constant
Therefore, the wagon that will accelerate faster is the wagon with less mass.
Hope this helps :)
Calculate the ph of a 0.005 m solution of potassium oxide k2o
Answers
K2O + H20 = 2 KOH
According to reaction K2O has base properties, so it forms a hydroxide in water.
For the reaction next relation follows:
c(KOH) : c(K2O) = 1 : 2
So,
c(KOH)= 2 x c(K2O)= 2 x 0.005 = 0.01 M = c(OH⁻)
Now we can calculate pH:
pOH= -log c(OH⁻) = -log 0.01 = 2
pH= 14-2 = 12
The pH of the 0.005 M K₂O solution is 12. This is calculate using K₂O dissociation in water and then dealing with concentrations.
To calculate the pH of a 0.005 M solution of potassium oxide (K₂O), first, we need to understand how K₂O dissociates in water. Potassium oxide reacts with water to form potassium hydroxide (KOH), which completely dissociates in water:
K₂O + H₂O → 2 KOH
Given the 0.005 M concentration of K₂O, it will produce an equivalent concentration of 0.01 M KOH because one K₂O produces two KOH molecules.
Next, KOH fully dissociates into K⁺ and OH⁻ ions:
KOH → K⁺ + OH⁻
This means the concentration of OH⁻ is also 0.01 M. To find the pOH of the solution, use the following formula:
pOH = -log[OH⁻]
So,
pOH = -log(0.01) = 2
Now, we can calculate the pH using the formula:
pH = 14 - pOH
So,
pH = 14 - 2 = 12
Therefore, the pH of the 0.005 M K₂O solution is 12.
The half-equivalence point of a titration occurs half way to the end point, where half of the analyte has reacted to form its conjugate, and the other half still remains unreacted. if 0.500 moles of a monoprotic weak acid (ka = 5.0 × 10-5) is titrated with naoh, what is the ph of the solution at the half-equivalence point?
Answers
Chemical reaction: HA + NaOH → NaA + H₂O.
n₀(HA) = 0,500 mol.
Ka = 5,0·10⁻⁵.
Half of the analyte has reacted, so n(HA) = 0,5 mol ÷ 2 = 0,25 mol.
From chemical reaction: n(HA) : n(NaOH) = 1 : 1.
n(NaOH) = n(NaA) = 0,25 mol.
pH = pKa + log(n(NaA)/n(HA).
pH = -log(5,0·10⁻⁵) + log (0,25 mol/0,25 mol).
pH = 4,30.
Which of the following orbitals is the largest in size?
A. 2s
B. 4s
C. 1s
D. 3s
E. all s orbitals are the same size
Answers
The orbital which is the largest in size is 4s.
Hence option (B) is correct.
What is Shape of S-orbital ?The shape of s-orbital is spherical around the nucleus of the atom. S-orbital have the probability to find the electrons at a given distance which is equal in all the directions.
Now lets check all options one by one
Option (A): 2s is a larger sphere than 1s but not 4s.
So, option A is incorrect.
Option (B): Here 1s is a small sphere, 2s is a larger sphere, 3s is more larger than 2s and 1s and 4s is the largest orbital from all of these.
So, option B is correct.
Option (C): 1s is smallest sphere from all of these.
So option C is incorrect.
Option (D): 3s is also smaller than 4s orbital.
So option D is incorrect.
Option (E): All the s-orbital have the same shape which is spherical not same size.
So option E is incorrect.
Thus, from above conclusion we can say that the orbitals which is largest in size is 4s.
The correct answer is option (B).
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Cyanide poisoning can occur when compounds such as sodium cyanide dissociate in water to produce cyanide ions. what is the formula for sodium cyanide?
Answers
The fromula for sodium cyanide is NaCn.
The formation of a condensation polymer generally involves ________. the elimination of a small molecule the addition of a plasticizer the vaporization of a plasticizer the mixing of sulfur with an addition polymer the formation of significant crosslinking
Answers
Plasticizers do not polymerize, but they change mechanical properties. The addition of sulfur and crosslinks are mainly for rubber in vulcanization, but not so much for condensation polymers.
I need help on all of these
Answers
Chemical reaction: 2Cl₂ + Sn → SnCl₄.
n(Cl₂) = 2,85 mol.
From chemical reaction: n(Cl₂) : n(SnCl₄) = 2 : 1.
n(SnCl₄) = n(Cl₂) ÷ 2.
n(SnCl₄) = 2,85 mol ÷ 2.
n(SnCl₄) = 1,425 mol.
n - amount of substance.
2) Answer is: mass of lithium is 128,04 grams.
Chemical reaction: 6Li + N₂ → 2Li₃N.
m(N₂) = 86,1 g.
n(N₂) = m(N₂) ÷ M(N₂).
n(N₂) = 86,1 g ÷ 28 g/mol.
n(N₂) = 3,075 mol.
From chemical reaction: n(N₂) : n(Li) = 1 : 6.
n(Li) = 6 · 3,075 mol.
n(Li) = 18,45 mol.
m(Li) = 18,45 mol · 6,94 g/mol.
m(Li) = 128,04 g.
3) Answer is: 69,77 grams of oxygen can be produced.
Chemical reaction: 2Cr(ClO₃)₃ → 2CrCl₃ + 9O₂.
m(Cr(ClO₃)₃) = 146,5 g.
n(Cr(ClO₃)₃) = m(Cr(ClO₃)₃) ÷ M(Cr(ClO₃)₃).
n(Cr(ClO₃)₃) = 146,5 g ÷ 302,35 g/mol.
n(Cr(ClO₃)₃) = 0,48 mol.
From chemical reaction: n(Cr(ClO₃)₃) : n(O₂) = 2 : 9.
n(O₂) = 2,18 mol.
m(O₂) = 2,18 mol · 32 g/mol.
m(O₂) = 69,77 g.
4) Answer is: volume of hydrogen is 97,47 dm³.
Chemical reaction: 2Al + 6H₂O → 2Al(OH)₃ + 3H₂.
m(Al) = 78,33 g.
n(Al) = m(Al) ÷ M(Al).
n(Al) = 78,33 g ÷ 27 g/mol.
n(Al) = 2,9 mol.
From chemical reaction: n(Al) : n(H₂) = 2 : 3.
n(H₂) = 2,9 mol · 3 ÷ 2.
n(H₂) = 4,35 mol.
V(H₂) = n(H₂) · Vm.
V(H₂) = 4,35 mol · 22,4 dm³/mol.
V(H₂) = 97,47 dm³ (L).
Vm - molar volume.
5) Answer is: there is 5,47·10²⁴ atoms of copper.
Chemical reaction: 6Cu + N₂ → 2Cu₃N.
V(N₂) = 33,9 L.
n(N₂) = V(N₂) ÷ Vm.
n(N₂) = 33,9 L ÷ 22,4 L/mol.
n(N₂) = 1,513 mol.
From chemical reaction: n(N₂) : n(Cu) = 1 : 6.
n(Cu) = 6 · 1,513 mol.
n(Cu) = 9,08 mol.
N(Cu) = n(Cu) · Na.
N(Cu) = 9,08 mol · 6,022·10²³ 1/mol.
N(Cu) = 5,47·10²⁴.
Na - Avogadro number.
What volume of a 2.5 M stock solution of acetic acid (HC2H3O2) is required to prepare
100.0 milliliters of a 0.50 M acetic acid solution?
Use the equation
Mconcentrated × Vconcentrated = Mdilute × Vdilute
Answers
c₁(CH₃COOH) = 2,5 M.
c₂(CH₃COOH) = 0,5 M.
V₂(CH₃COOH) = 100 mL.
V₁(CH₃COOH) = ?
c₁(CH₃COOH) · V₁(CH₃COOH) = c₂(CH₃COOH) · V₂(CH₃COOH).
2,5 M · V₁(CH₃COOH) = 0,5 M · 100 mL.
V₁(CH₃COOH) = 0,5 M · 100 mL ÷ 2,5 M.
V₁(CH₃COOH) = 20 mL ÷ 1000 mL/L =0,02 L.
A solution was prepared by dissolving 25.0 g of kcl in 225 g of water. calculate the mass percent of kcl in the solution.
Answers
The mass percent of KCl mass would be: 25g/ 250g= 10%
Final answer:
The mass percent of KCl in the solution is calculated by dividing the mass of KCl by the total mass of the solution and then multiplying by 100%, resulting in a mass percent of 10%.
Explanation:
To calculate the mass percent of KCl in the solution, you can use the formula: (mass of solute ÷ mass of solution) × 100%. First, calculate the mass of the solution by adding the mass of KCl and the mass of water. In this case, it would be 25.0 g of KCl + 225 g of water, which equals 250.0 g of solution.
Now, take the mass of KCl (25.0 g) and divide it by the mass of the solution (250.0 g). Multiply the result by 100% to get the mass percent of KCl in the solution.
So, the calculation is (25.0 g ÷ 250.0 g) × 100% which equals 10%. Therefore, the mass percent of KCl in the solution is 10%.
For the gas phase decomposition of 1-bromopropane, CH3CH2CH2BrCH3CH=CH2 + HBr the rate constant at 622 K is 6.43×10-4 /s and the rate constant at 666 K is 8.28×10-3 /s. The activation energy for the gas phase decomposition of 1-bromopropane is
Answers
Answer
is: activation energy of this reaction is 212,01975 kJ/mol.
Arrhenius equation: ln(k₁/k₂) =
Ea/R (1/T₂ - 1/T₁).
k₁
= 0,000643 1/s.
k₂
= 0,00828 1/s.
T₁ = 622 K.
T₂ = 666 K.
R = 8,3145 J/Kmol.
1/T₁ =
1/622 K = 0,0016 1/K.
1/T₂ =
1/666 K = 0,0015 1/K.
ln(0,000643/0,00828) = Ea/8,3145 J/Kmol ·
(-0,0001 1/K).
-2,55 = Ea/8,3145 J/Kmol · (-0,0001 1/K).
Ea = 212019,75 J/mol = 212,01975 kJ/mol.
Final answer:
To find the activation energy for 1-bromopropane's decomposition, use the Arrhenius equation with given rate constants and temperatures, resulting in a calculated activation energy.
Explanation:
To calculate the activation energy for the gas-phase decomposition of 1-bromopropane, we can use the Arrhenius equation which relates the rate constant (k) of a reaction to the temperature (T) and activation energy (Ea). The equation in its logarithmic form is:
ln(k2/k1) = (Ea/R) * (1/T1 - 1/T2)
Where:
k1 = 6.43×10-4 /s and k2 = 8.28×10-3 /s are the rate constants at temperatures T1 and T2, respectively
Using the Arrhenius equation:
ln(8.28×10-3 / 6.43×10-4) = (Ea/8.314) * (1/622 - 1/666)
After calculating:
Ea = ((ln(8.28×10-3 / 6.43×10-4)) * 8.314) / (1/622 - 1/666)
This gives the activation energy for the gas-phase decomposition of 1-bromopropane.
calculate the percent of lead in Pb (Co3)2
Answers
M(Pb(CO3)2) = Ar(Pb) + 2xAr(C) + 6xAr(O) = 207.2 + 2x12 + 6x16= 327.2 g/mol
M(Pb) = 207.2 g/mol
From the date above we can set the following ratio:
M(Pb(CO3)2) : M(Pb) = 100% : x
327.2 : 207.2 = 100 :x
x = 63.33% of Pb there is in Pb(Co3)2
The percent of lead in Pb(CO3)2 is calculated by dividing the molar mass of the lead by the molar mass of the entire compound and then multiplying by 100, resulting in 63.31% lead content.
Explanation:To calculate the percent of lead in Pb(CO3)2, first, we need to determine the molar mass of the compound. The molar mass of lead (Pb) is 207.2 u, and the molar mass of carbonate (CO3) is 60.01 u (with 3 oxygens at 16.0 u each plus one carbon at 12.01 u).
The molar mass of the lead carbonate compound is:
Lead (Pb): 207.2 uCarbonate (CO3): 2 x (12.01 u + 3 x 16.0 u) = 2 x 60.01 u = 120.02 uAdding these together, the molar mass of Pb(CO3)2 is 207.2 u + 120.02 u = 327.22 u.
To find the percent of lead in the compound, divide the molar mass of lead by the total molar mass of the compound and multiply by 100:
Percent of lead = (207.2 u / 327.22 u) x 100 = 63.31%
Therefore, the percent of lead in lead carbonate is 63.31%.
Starting with acetylene and bromoethane, show how you would use reagents from the table to synthesize 4-methyl-3-hexanone. (enter your choices as a string of letters without punctuation, i.e. ace.)
Answers
With the 3-hexyne in hand, the triple bond is reduced using Lindlar's catalyst which will hydrogenate only to the alkene and stop. The 3-hexene is then reacted with a peroxycarboxylic acid which is used to epoxidize the alkene, to give the epoxide.
The epoxide is reacted with the grignard reagent which treats the methyl as a strong nucleophile. The methyl adds to one carbon of the epoxide and opens the ring. The acid is added at the end to protonate the alcohol.
Finally, the alcohol is oxidized with chromic acid which will oxidize a secondary alcohol to the ketone. The final product is 4-methyl-3-hexanone.
Calculate the mass of aluminum in 250 g of Al(C2H3O2)3
Answers
Nacl(aq)+hg2(c2h3o2)2(aq)→ express your answer as a chemical equation. enter noreaction if no reaction occurs. identify all of the phases in your answer. nac2h3o2(aq)+hg2cl2(s)nac2h3o2(aq)+hg2cl2(s)
Answers
The chemical reaction of NaCl with H₂O, leading to the formation of NaOH, H₂, and Cl₂, can be expressed as a balanced molecular equation, a complete ionic equation, and a simplified net ionic equation, where Na⁻ and Cl⁻ act as spectator ions.
The initial equation provided, NaCl(aq) + H₂O(1) → NaOH(aq) + H₂(g) + Cl₂ (g), is an example of a chemical reaction involving the decomposition of sodium chloride (NaCl) in the presence of water to form sodium hydroxide (NaOH), hydrogen gas (H₂), and chlorine gas (Cl₂).
The balanced molecular equation for this reaction is:
2NaCl(aq) + 2H₂O(l) → 2NaOH(aq) + H₂(g) + Cl₂ (g)
The complete ionic equation would be:
2Na+ (aq) + 2Cl + (aq) + 2H₂O(l) → 2Na+ (aq) + 2OH - (aq) + H₂(g) + Cl₂ (g)
And the net ionic equation simplifies to:
2H₂O(l) → H₂(g) + Cl₂ (g), since Na⁺ and Cl ⁻ are spectator ions and do not participate in the reaction.
the variable that a scientist changes when conducting an experiment is called the _____variable.
a. dependent
b.responding
c.manipulated
Answers
Answer: The correct answer is option (a).
Explanation:
Dependent variables are the variables whose value depend on another variable. Its value changes as the independent variable changes.
Independent variables are the variables which do not depend on any other variable beside . Its value does not change with a change in other dependent variables.
While conducting experiment scientist changes dependent variable in order to record observations.
Formaldehyde, h2c=o, is known to all biologists because of its usefulness as a tissue preservative. pure formaldehyde trimerizes to give trioxane, c3h6o3, which, surprisingly enough, has no carbonyl groups. only one monobromo derivative (c3h5bro3) of trioxane is possible. propose a structure for trioxane.
Answers
Please find the attached which illustrate the trimerize of the formaldehyde (HCHO) to form trioxane (C3H6O3)
Using the given data, calculate the rate constant of this reaction.
Answers
when Rate = K [A]^x * [B]^z
So to get the rate we have to get X & Z
first, we choose two value of [A] which [A] changed and [B] still constant
that appears in trial 1 & 3 SO, we will use Rate 1 & rate 3 and [A1] &[A3] and we can neglect [B] as it is constant:
Rate3/Rate1 = ([A3]/[A1])^x
0.0852/0.0213 = (0.62/0.31)^x
4 = 2^x ∴ X = 2
- second, we have to choose two value of [B] which [B] changed and [A] still constant and that appears in trail 1&2, we will use the rate 1 &2 and [B1] & [ B2] and we can neglect [A] as it is constant:
Rate 2 / Rate 1 = ([B2]/[B1])^z
0.0213/0.0213 = (0.68/0.34)^z
1 = 2^z ∴ Z= zero
SO Rate1 = K [A]^2[B]^0
0.0213 = K * (0.31)^2 *1
∴ K = 0.222 m^-1.S^-1
Describe how the periodic table differentiates between metals and nonmetals. what type of element is most abundant: metals, nonmetals, or metalloids? give the names and symbols of three metalloids from the periodic table. identify items in your life that are made of each type of element: metal, nonmetal, and metalloid. for each item, explain why the properties of that type of element are necessary for the function of that item. prezi
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1. Elements of the periodic system are divided into three groups of metals, nonmetals, and metalloids. Metals in the periodic table are separated of nonmetals by metalloids. Metals are located on the left side and the nonmetals on the right side of the periodic table. On a periodic table often is showed a stair-step line from boron to polonium which represents metan-nonmetal border. The only exception is hydrogen that is nonmetal although it is situated on the left side.
2. The most numerous elements in the periodic system are metals. At the moment, there are a total of 94 metals. There are 38 transition metals, 15 lanthanides, 15 actinides, 6 alkali metals, 6 alkaline earth metals, and 14 post-transition Metals. As regarding nonmetals, their number in the periodic table is 17 and there are 7 metalloids.
3. Metal: I would choose a copper wire, made as the name suggests from a copper that has the ability to perfectly conduct electricity.
Metalloid: I would choose a smartphone that contains computer chips made from silicon that has the property of a semiconductor.
Nonmetal: I would choose a camera flash that contains xenon, a gas which produces a white flash light when it is electrically excited.
4. Boron is a metalloid with the chemical symbol B and a serial number 5. In the periodical system, it is located in the 13th group and 2nd period.
Silicon is a metalloid with the chemical symbol Si and a serial number 14. In the periodical system, it is located in the 14th group and 3rd period.
Antimony is a metalloid with the chemical symbol Sb and serial number 51. In the periodical system, it is located in the 15th group and 5th period.
The anticaking agent added to table salt is calcium metasilicate (casio3). this compound can absorb up to 2.5 times its mass in water and still remain a free-flowing powder. calculate the percent composition of casio3.
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Ca = 40.1 g/mol
Si = 28.1 g/mol
O = 16.0 g/mol
The total molecular weight is as follows:
[(40.1 g/mol) x 1 mol Ca] + [28.1 g/mol x 1 mol Si] + [(16 g/mol) x 3 mol O] = 116.2 g/mol
Now that we have the total mass of CaSiO₃, we can calculate the percent composition in 1 mol of CaSiO₃:
% Ca = [(40.1 g/mol x 1 mol Ca)/116.2 g] x 100% = 34.5% Ca
% Si = [(28.1 g/mol x 1 mol Si)/116.2 g] x 100% = 24.2% Si
% O = [(16 g/mol x 3 mol O)/116.2 g] x 100% = 41.3% O
The percent composition of CaSiO₃ is found to be 34.5% Ca, 24.2% Si and 41.3% O.
The percent composition of calcium metasilicate (CaSiO₃) is approximately 34.49% calcium, 24.17% silicon, and 41.33% oxygen.
To calculate the percent composition of a compound, you need to determine the molar mass of each element in the compound and then divide by the total molar mass of the compound. Here’s the step-by-step breakdown:
Calculate the molar masses:
Calcium (Ca): 40.08 g/molSilicon (Si): 28.09 g/molOxygen (O): 16.00 g/mol per atom. Since there are three oxygen atoms, the total is 3 x 16.00 = 48.00 g/mol.Determine the molar mass of CaSiO₃:
The total molar mass of CaSiO₃ is 40.08 + 28.09 + 48.00 = 116.17 g/mol.
Calculate the percent composition:
Percent composition of Ca: (40.08 / 116.17) x 100 ≈ 34.49%Percent composition of Si: (28.09 / 116.17) x 100 ≈ 24.17%Percent composition of O: (48.00 / 116.17) x 100 ≈ 41.33%So, the percent composition of CaSiO₃ is approximately 34.49% calcium, 24.17% silicon, and 41.33% oxygen.
If the concentration of cucl2 drops from 1.000 m to 0.655 m in the first 30.0 s of the reaction, what is the average rate of reaction over this time interval?
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The average rate of reaction is calculated by dividing the change in concentration of a reactant or product by the time interval. For CuCl₂ decreasing from 1.000 M to 0.655 M in 30.0 s, the average rate of reaction is 0.0115 M/s.
The average rate of reaction over a given time interval can be determined by calculating the change in concentration of a reactant or product and dividing by the time interval over which the change occurred. In the scenario provided, the concentration of CuCl₂ decreases from 1.000 M to 0.655 M over a period of 30.0 seconds. To calculate the average rate of reaction, we follow these steps:
Identify the initial concentration and final concentration of CuCl₂. In this case, [tex]C_{i}[/tex]= 1.000 M and [tex]C_{f}[/tex] = 0.655 M.Calculate the change in concentration (ΔC) using the formula ΔC = [tex]C_{f}[/tex]- [tex]C_{i}[/tex]. Therefore, ΔC = 0.655 M - 1.000 M = -0.345 M. The negative sign indicates a decrease in concentration.Determine the time interval (t) over which the change in concentration has occurred, which is given as 30.0 s.Calculate the average rate of reaction (Rate) using the formula Rate = ΔC / t. The correct answer is thus Rate = -0.345 M / 30.0 s = -0.0115 M/s.The negative sign in rate typically indicates the consumption of a reactant. However, when discussing rates of reaction, it is common to report them as positive values, so the average rate of reaction from this calculation would be 0.0115 M/s.