Answer:
B.) It states that the change in enthalpy is independent of the pathway
the reaction takes to get to the products.
Explanation:
Hess's Law states that the overall enthalpy change is the sum of the enthalpy changes of all preceding steps. It does not matter how many steps there are or the type, so long as the enthalpy change of each is combined at the end, the overall change can be determined. The sequence (aka pathway) is not important.
reaction of cysteine and NaOH
Answer:
cysteine is HOOC-CH--CH₂-SH
reaction with Naoh
HOOC-CH--CH₂-SH + Naoh ---->oh-oNH2-oh + H2o
What’s the gravitational potential energy of a book 2.0 meters above the floor with a mass of 1.5 kilograms
Answer:
29.3 joules
Explanation:
P.E. = mgh
= 1.5 kg * 9.81 m/s^2 * 2 m = 29.3 Joules
Which of the following statements about carbon dioxide is not true?
Increased carbon dioxide in the atmosphere increases the Greenhouse Effect.
Carbon dioxide is a greenhouse gas.
Atmospheric carbon dioxide levels have slowly declined over the last 50 years.
Burning fossil fuels can increase carbon dioxide levels in the atmosphere.
Question 3
What part of a water molecule is the negatively charged side?
Answer:
The oxygen atom in water has a negative charge.
Definitions:Polar molecule: A molecule in which the centroid of the positive charges is different from the centroid of the negative charges.
Oxygen: A colorless, odorless, gaseous element constituting about one-fifth of the volume of the atmosphere and present in a combined state in nature. It is the supporter of combustion in air and was the standard of atomic, combining, and molecular weights until 1961, when carbon 12 became the new standard. Symbol: O; atomic weight: 15.9994; atomic number: 8; density: 1.4290 g/l at 0°C and 760mm pressure.
Water: A transparent, odorless, tasteless liquid, a compound of hydrogen and oxygen, H2O, freezing at 32°F or 0°C and boiling at 212°F or 100°C. that in more or less impure state constitutes rain, oceans, lakes, rivers, etc.: it contains 11.188 percent hydrogen and 88.812 percent oxygen, by weight.
Hydrogen: A colorless, odorless, flammable gas that combines chemically with oxygen to form water: the lightest of the known element. Symbol: H; atomic weight: 1.00797; atomic number: 1; density: 0.0899 g/l at 0°C and 760 mm pressure.
Atom: Am atom is the smallest constituent particle of a chemical element which has the properties of that element. They re comprised of at least an electron and a portion, as is the case for Hydrogen. Atoms of all other elements however, contain at least one neutron.
Proton: A positively charged elementary particle that is a fundamental constituent of all atomic nuclei. It is the lightest and most stable baryon, having a charge equal in magnitude to that of the electron, a spin of 1/2, and a mass of 1.673 × 10-27kg. Symbol: P.
Electron: An elementary particle that is a fundamental constituent of matter, having a negative charge of 1.602 × 10-19 coulombs, ha mass of 9.108 × 10-31 kilograms, and spin of 1/23, and existing independently or as the component outside the nucleus of an atom.
Neutron: An elementary particle having no charge, mass slightly greater than that of a proton, and spin of 1/2: a constituent of the nuclei of all atoms except those of hydrogen. Symbol: n.
What is a negative charge?A object has a negative charge when it consists of more electrons than protons.
With a partial positive charge on 2 Hs and a partial negative charge on oxygen, water molecules are polar molecules.
Actually, two hydrogen atoms and the core oxygen atom of water are covalently connected. Due to its greater electronegative nature than hydrogen, oxygen pulls the bound electron pair in the middle of the atom toward it.
When illustrating higher electron densities over oxygen, partial negative charge is used, whereas partial positive charge is used to illustrate lower densities over hydrogen atoms.
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Predict the nature of the indicated
covalent bond.
non-polar
Explanation :
Hydrogen and carbon have similar electronegativity values, so the C—H bond is not normally considered a polar covalent bond.
What is the SI unit used to measure weight?
Answer:
The si unit used to measure weight is kilogram /kg
If a utility burned 7.57 million tons of coal that was 2.00% sulfur by weight, how many tons of sulfur dioxide were emitted? Answer in scientific notation.
So mass of sulphur
[tex]\\ \rm\Rrightarrow 0.02\times 757\times 10^{6}[/tex]
[tex]\\ \rm\Rrightarrow 1514\times 10^4[/tex]
S+O_2–≥SO_2Moles =64/32=2
So
So tons of sulphur dioxide
[tex]\\ \rm\Rrightarrow 2(1516)10^4[/tex]
[tex]\\ \rm\Rrightarrow 3032\times 10^4ton[/tex]
Explanation:
2% of 2million tons of sulphur=
2÷100×7.57E9
That is;
[tex] \frac{2}{100} \times 7.57 \times 10 {}^{6} = 0.02 \times 7.57 \times 10 {}^{6} \\ = 2 \times 10 {}^{ - 2} \times7.57 \times 10 {}^{6} = 2 \times 7.57(10 {}^{ - 2 + 6}) \\ = 15.14 \times 10 {}^{4} (for \: sulphur) \\ for \: sulphur \: dioxide = so2 \\ the \: molar \: mass \: of \: so2 = 64g.mol {}^{ -1} \\ if \: 32grams \: of \: sulphur \: weighs \: 15.14 \times 10 {}^{4} tones \\ 64grams \: will \: weigh \: \frac{64}{32} \times 15.14 \times 10 {}^{4} \\ = 2 \times 15.14 \times 10 {}^{4} \\ = 30.28 \times 10 {}^{4} \\ or = 3.028 \times 10 {}^{5} tones[/tex]
The absolute molar entropies of O2 and N2 are 205 J K-1 mol -1 and 192 J K-1 mol-1, respectively, at 25°C. What is the entropy of a mixture of 2.4 moles of 02 and 9.2 moles of N2 at the same temperature and pressure?
The entropy of a mixture is 96.44J K-1 mol -1
The absolute molar entropies of O2= 205 J K-1 mol -1 The absolute molar entropies of N2=192 J K-1 mol -1 Moles of O2 present(m)=2.4Moles of N2 present(n)=9.2The formula for calculating the entropy of a mixture-
Δ[tex]S_{mix} =[/tex][tex]-nR(X_{O2} ln_{XO2} +X_{N2} lnX_{N2})[/tex]
X=mole fraction
total no. of moles(t)=m + n
=2.4+9.2
=11.6 moles
now substituting the values-
entropy of mix=-11.6R(2.4/11.6 + 9.2/11.6)
=11.6R
( R=8.314 ) =11.6×8.314
=96.44J K-1 mol -1
hence, The entropy of a mixture is 96.44J K-1 mol -1
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For the following reaction, 22.0 grams of nitrogen monoxide are allowed to react with 5.80 grams of hydrogen gas . nitrogen monoxide ( g ) + hydrogen ( g ) nitrogen ( g ) + water ( l ) What is the maximum amount of nitrogen gas that can be formed? grams What is the FORMULA for the limiting reagent? What amount of the excess reagent remains after the reaction is complete? grams
NO is the limiting reagent and 4.34 g is the amount of the excess reagent that remains after the reaction is complete
What is a limiting reagent?The reactant that is entirely used up in a reaction is called as limiting reagent.
The reaction:
[tex]2NO(g) +2H_2(g)[/tex] → [tex]N_2 +2H_2O[/tex]
Moles of nitrogen monoxide
Molecular weight: [tex]M_(_N_O_)[/tex]=30g/mol
[tex]n_(_N_O_) =\frac{mass}{molar \;mass}[/tex]
[tex]n_(_N_O_) =\frac{22.0}{30g/mol}[/tex]
[tex]n_(_N_O_) = 0.73 mol[/tex]
Moles of hydrogen
Molecular weight: [tex]M_(_H_2_)[/tex]=30g/mol
[tex]n_(_H_2_) =\frac{mass}{molar \;mass}[/tex]
[tex]n_(_H_2_) =\frac{5.80g}{2g/mol}[/tex]
[tex]n_(_H_2_) = 2.9 mol[/tex]
Hydrogen gas is in excess.
NO is the limiting reagent.
The amount of the excess reagent remains after the reaction is complete.
[tex]n_(_N_2_) =[/tex] (2.9 mol- 0.73 mol NO x [tex]\frac{1 \;mol \;of \;H_2}{2 \;mole \;of \;NO}[/tex]) x [tex]\frac{2g \;of \;H_2}{mole \;of \;H_2}[/tex]
[tex]n_(_N_2_) =[/tex]4.34 g
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Given the following equation, how many grams of PbCO3 will dissolve when 2.50 L of 1.50 M H+ is added to 3.00 g of PbCO3?
Given
PbCO3(s) + 2H+(aq) = Pb^2(aq)+ +H2O (l)+ CO2(g)
A student uses a solution of 1.2 molar sodium hydroxide (NaOH) to calculate the concentration of a solution of sulfuric acid (H2SO4). She records a neutral pH after adding 20 mL of the sodium hydroxide solution to 50 mL of the sulfuric acid solution.
What is the concentration of the sulfuric acid solution?
A.
0.24 M
B.
0.12 M
C.
2.1 M
D.
1.0 M
E.
0.48 M
From the calculations, the concentration of the acid is 0.24 M.
What is neutralization?The term neutralization has to do with a reaction in which an acid and a base react to form salt and water only.
We have to use the formula;
CAVA/CBVB = NA/NB
CAVANB =CBVBNA
The equation of the reaction is; 2NaOH + H2SO4 ----> Na2SO4 + 2H2O
CA = ?
CB = 1.2 M
VA = 50 mL
VB = 20 mL
NA = 1
NB = 2
CA = CBVBNA/VANB
CA = 1.2 M * 20 mL * 1/ 50 mL * 2
CA = 0.24 M
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The heat of vaporization of water is 540 cal/g. How much heat is needed to change 4.28g of water to steam?
Answer:
2311.2 cal
Explanation:
540 cal / g * 4.28 g = 2311.2 cal
2311.2 cal heat is needed to change 4.28g of water to steam.
What is heat?Heat is the transfer of kinetic energy from one medium or object to another, or from an energy source to a medium or object.
The heat of vaporization is defined as the amount of heat needed to turn 1g of a liquid into a vapour, without a rise in the temperature of the liquid.
The heat of vaporization is equal to the thermal energy required for vaporization divided by the mass of the substance that is vaporizing. Its formula is Hv = q/m.
Putting the values in the formula:
540 cal / g x 4.28 g = 2311.2 cal
Hence, 2311.2 cal heat is needed to change 4.28g of water to steam.
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What would most likely happen when a metal is heated?
It will melt.
It will solidify.
Its temperature will decrease.
Its particles will move slower.
Answer: it is A i took the test i got it right
Explanation: i took the test
- How many grams are in 1.4 x 10¹5 atoms of calcium?
Answer:
40 g= 6.022×10²³
x=1.4×10¹⁵
x=40g×6.022×10²³/1.4×10¹⁵
x=17.77×10⁸
Barium nitrate (Ba(NO3)2) reacts with sodium chloride (NaCl) in a double replacement (displacement) reaction, shown below.
Ba(NO3)2(aq)+NaCl(aq)-->???
How many grams of barium salt are produced when a solution containing 21.7 g of Barium nitrate is mixed with a solution containing excess sodium chloride?
Use 261.34 as the molar mass for barium nitrate. Round to three significant digits.
Answer:
you know that they will be a displacement reaction that will form a barium salt:
Ba(NO3)2+ 2NaCl--> BaCl2 + 2NaNO3
So now that we have that formula and the molecular weight we can determine how much salt will be made. So here we convert the grams to moles
(42.3g Ba(NO3)2)*(1 mole/261.34g) = 0.16185 mol
In the molecular formula we know that 1 mole of Barium nitrate will create 1 mole of Barium chloride, so in this case (in a perfect world) you should get 0.16185 mole of barium chloride (208.23 g/mol) that we then have to convert to grams.
(0.16185 mol BaCl2) * ( 208.23 g/mol) = 33.7037 g of Barium Chloride (rounded to 3 significant digits = 33.7g)
B. Flourine is the right answer
Answer:
Whts ur question??
..?
Explanation:
Was this by mistake or smthin
HELP! ASAP!
1. Using the model below, identify the products, reactants, and limiting reactant in the chemical reaction. Please provide an explanation of your reasoning. In addition, write the balanced chemical equation for the reaction that is taking place in the chamber.
Given the model from the question,
The products are: N₂, H₂O and H₂The reactants are: H₂ and NOThe limiting reactant is H₂The balanced equation is: 3H₂ + 2NO —> N₂ + 2H₂O + H₂Balanced equationFrom the model given, we obtained the ffolowing
Red => Oxygen Blue => Nitrogen White => HydrogenThus, we can write the balanced equation as follow:
3H₂ + 2NO —> N₂ + 2H₂O + H₂
From the balanced equation above,
Reactants: H₂ and NOProduct: N₂, H₂O and H₂How to determine the limiting reactant3H₂ + 2NO —> N₂ + 2H₂O + H₂
From the balanced equation above,
3 moles of H₂ reacted with 2 moles of NO.
Therefore,
5 moles of H₂ will react with = (5 × 2) / 3 = 3.33 moles of NO
From the calculation made above, we can see that only 3.33 moles of NO out of 4 moles given are required to react completely with 5 moles of H₂.
Thus, H₂ is the limiting reactant
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In a container with 512.1 L water, the pH should be changed to 5 using 95% sulfuric acid. The question is how much sulfuric acid is needed.
Answer:
15
Explanation:
I got it right I just had the answer
Aqueous Copper (II) nitrate reacts with aqueous potassium iodide to form Copper (II) iodide solid and potassium nitrate
Answer:
Cu(NO₃)₂ (aq) + 2 KI (aq) ---> CuI₂ (s) + 2 KNO₃
Explanation:
When writing the reaction with the symbols, you need to take into account the charges of the ions. If he charges on the ions do not balance out in a molecule, they need to be made up for in the form of subscripts. For example, copper (+2) and iodine (-1) have charges which do not balance. Thus, to make the molecule neutral, you need to have two iodine atoms (CuI₂).
The unbalanced equation:
Cu(NO₃)₂ (aq) + KI (aq) ---> CuI₂ (s) + KNO₃
Reactants: 1 copper, 2 nitrate, 1 potassium, 1 iodine
Products: 1 copper, 1 nitrate, 1 potassium, 2 iodine
The balanced equation:
1 Cu(NO₃)₂ (aq) + 2 KI (aq) ---> 1 CuI₂ (s) + 2 KNO₃
Reactants: 1 copper, 2 nitrate, 2 potassium, 2 iodine
Products: 1 copper, 2 nitrate, 2 potassium, 2 iodine
Which element has properties most like Mg?
Answer:
The elements which are in the group
The standard oxidation-reduction potential of a system Fe3+ —> Fe2+ is 0.77 V. What is the ratio of the oxidized form concentration to the reduced form concentration if E = 0.711 V?
Based on the oxidation-reduction potential of the system, ratio of the concentration of the oxidized form to the concentration of the reduced form is 1 : 10.
What is standard oxidation-reduction potential of a system?The oxidation-reduction potential of a system is a measure of the tendency for a given chemical species to be reduced.
The reduction equation is as follows:
[tex]Fe^{3+} \rightarrow Fe^{2+} = 0.77\:V[/tex]
Using the equation:
[tex]E = E^{o} - \frac{0.0592}{n}log\frac{[Fe^{2+}]}{[Fe^{3+}]}[/tex]
n = 1; E⁰ = 0.77; E = 0.711
Substituting the values and using 1/x as the ratio:
[tex]0.711 = 0.77 - \frac{0.0592}{1} * log\frac{1}{x}[/tex]
x = 1/10
Therefore, the ratio of the concentration of the oxidized form to the concentration of the reduced form is 1 : 10.
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Calculate the pH of a solution with [H+] = 2.52 x 10^-5.
Answer:
pH = 4.6
Explanation:
pH is the negative of the log of the hydrogen ion concentration
- log { 2.52 x 10^-5) = ~ 4.6
Which statement best explains why gneiss is composed of layers but there are no layers in granite?
Gneiss is a sedimentary rock and granite is a metamorphic rock.
Gneiss is a metamorphic rock and granite is a sedimentary rock.
Granite is formed due to the slow cooling of magma below Earth's surface and gneiss is formed due to metamorphosis.
Granite is formed due to the accumulation of sediments and gneiss is typically formed due to intense heat and pressure.
Gneiss is a sedimentary rock and granite is a metamorphic rock. That is option A.
What are rocks?Rocks are geological hard materials that are made up of various types which include:
Sedimentary rocks: These are rocks that made up of various layers formed from sediments. Example is the gnesis.Metamorphic rocks: These are rocks that are form from pre existing rocks that undergoes some transformation. Example is graniteTherefore, Gneiss is a sedimentary rock and granite is a metamorphic rock.
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Answer:
C
Granite is formed due to the slow cooling of magma below Earth's surface and gneiss is formed due to metamorphosis.
Explanation:
I took the test!
Question 5 of 10
Platinum has a density of 21 g/cm³. A platinum ring is placed in a graduated
cylinder that contains water. The water level rises from 4.0 mL to 4.2 mL
when the ring is added. What is the mass of the ring?
A. 2.6 g
OB. 3.8 g
OC. 4.2 g
OD. 5.2 g
B
Answer:
4.2 g
Explanation:
The VOLUME of the ring is 4.2 - 4.0 = .2 ml = .2 cm^3
the MASS of the ring is this times the density
.2 cm^3 * 21 g/cm^3 = 4.2 g
Answer:
the answer is c
Explanation:
density is mass/volume
so mass=density × volume
but we take the change is volume that is v2-v2=4.2-4=0.2ml
but the density is in gm/cm^3 so we should convert ml into cm^3. eventually they are equal so mass=21×0.2=4.2
The concentration of lead nitrate Pb(NO3)2
in a 0.726 M solution is __________ molal. The
density of the solution is 1.202 g/mL.
Answer: The concentration of lead nitrate Pb(NO3)2 in a 0.726 M solution is 0.755 molal.
Explanation:
Given:
The molar mass of Pb(NO3)2 is 331.2 g/mol
Assuming 1 litre of solution. This would equal 1202 g of solution
In the one litre of solution, you have 0.726 mol Pb(NO3)2
0.726 mol (331.2 g/mol) = 240.5 g Pb(NO3)2
Mass of water in 1 L of solution = 1202 g - 240.5 g = 961.5 g = 0.9615 kg
Molality = mols of solute / kg of solvent
= 0.726 mol / 0.9615 kg
= 0.755 m Pb(NO3)2
Hydrogen and iodine vapour exist in equilibrium with hydrogen iodide at a constant temperature in a gas syringe.
H2 + I2
2HI
Which of the following will increase when the pressure is increased at constant temperature? [Assume that the mixture shows ideal behavior.]
The pressure has no effect on the equilibrium constant.
What is Equilibrium ?Equilibrium is a state when the forward reaction rate is equal to the backward reaction rate .
The equation given is
H₂ + I₂ ⇄ 2HI
The Equilibrium constant depends only upon temperature and nature of reaction ,
It is independent of catalyst presence , initial concentration of reactants,and pressure.
The pressure has no effect on the equilibrium constant.
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How many grams of KCl 03 are needed to produce 6.75 Liters of O2 gas measured at 1.3 atm pressure and 298 K?
11.48-gram of [tex]KCl0_3[/tex] are needed to produce 6.75 Liters of [tex]O_2[/tex] gas measured at 1.3 atm pressure and 298 K
What is an ideal gas equation?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
First, calculate the moles of the gas using the gas law,
PV=nRT, where n is the moles and R is the gas constant. Then divide the given mass by the number of moles to get molar mass.
Given data:
P= 1.3 atm
V= 6.75 Liters
n=?
R= [tex]0.082057338 \;L \;atm \;K^{-1}mol^{-1}[/tex]
T=298 K
Putting value in the given equation:
[tex]\frac{PV}{RT}=n[/tex]
[tex]n= \frac{1.3 \;atm\; X \;6.75 \;L}{0.082057338 \;L \;atm \;K^{-1}mol^{-1} X 298}[/tex]
Moles = 0.3588 moles
Now,
[tex]Moles = \frac{mass}{molar \;mass}[/tex]
[tex]0.3588 moles = \frac{mass}{32}[/tex]
Mass= 11.48 gram
Hence, 11.48-gram of [tex]KCl0_3[/tex] are needed to produce 6.75 Liters of [tex]O_2[/tex] gas measured at 1.3 atm pressure and 298 K
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Predict the shape of the molecule.
The Correct option is A. octahedral
because the molecule has 6 sigma bonds that results into sp³d² hybridization.
and octahedral structure is formed
Answer:
Octahedral
Explanation:
You have a atom connected to 6 others and each of the bonds are similar
A dose of 156 mg of acetaminophen is prescribed for a 13−kg child. If one teaspoon contains 5.0 mL, how many teaspoons of Children’s Tylenol (80. mg of acetaminophen per 2.5 mL) must be administered?
Answer:
Just under 1 tsp
Explanation:
This is a situation where dimensional analysis is helpful....
156 mg / (80 mg / 2.5 ml * 5 ml / tsp ) =
156 mg / ( 160 mg/tsp) = .975 tsp ~~~ 1 tsp
Please help
Logan has been studying rocks at school. How could he learn more about the different types of rocks that come from volcanoes?
A.
collect rocks at the shore
B.
read comics about imaginary rocks
C.
explain to his sister how volcanoes form
D.
watch videos about volcanic rocks
Answer:
I think D is the answer. The others can't be answer. Specially B and D can't be the answer.
