Answer:
C. The second equation must be halved
D. The second equation must be reversed
E. The third equation must be halved.
Delta Hrxn= 131.3 kJ
Explanation:
The correct answer is -582 KJ.
What is the enthalpy of reaction?
Enthalpy is the heat content of a system.The enthalpy change of a reaction is roughly equivalent to the amount of energy lost or gained during the reaction.A reaction is favored if the enthalpy of the system decreases over the reaction.What is the overall enthalpy of the reaction?
Equal to the sum of the standard enthalpies of the intermediate reaction steps is called overall enthalpyLearn more about enthalpy below,
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Acetylene is the simplest hydrocarbon
that contains carbon-carbon triple bond.
Hydrocarbons are the compounds of
carbon and hydrogen.
identify the branch of Chemistry??
Answer:
organic chemistry
because it is study of carbon containing substances
Organic chemistry is the branch of Chemistry where hydrocarbons are the compounds of carbon and hydrogen.
What is organic chemistry?Organic chemistry is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds.
Hydrocarbons Derivatives are compounds which are made up of hydrogen and carbon with specific functional groups attached to them.
Examples:- Aldehydes, ketones, carboxylic acids, alcohols, alkyl halides, ethers, amines etc.
Hence, organic chemistry is the branch of Chemistry where
hydrocarbons are the compounds of carbon and hydrogen.
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If the temperature outside is 297 what is this temperature in degrees celsius
Answer:
147.222
Explanation:
It's a simple conversion.
what is the difference between basis and basic
Answer:
Basis and basic are two different words.
In English, Basis is used as a noun while basic is used as an adjective. Basis term refers as the base or starting point of any discussion.
For example: Bread is a basic ingredient of cake.
On the basis of Mendel's hypothesis.
In chemistry, Basis set is used as a set of functions that represent the electronic wave function in the density-functional theory which forms an algebraic equations that can be easily implemented on a computer.
While Basic term is used for substances that can accept a hydrogen ion (H+) from another substance and have pH above 7. such as sodium.
So, It is not important that both the terms, basis and basic change their English meaning if used in chemistry, they both can be used with English meaning in chemistry as well. Bases and basic, both the terms can be used as either English or Chemistry without affecting the meaning.
Un hidrocarburo tiene como composición en masa: C= 85.8% ; H= 14.2% . Como dato nos brindan que una molécula de este compuesto pesa: LaTeX: 2.1x10^{-22}g2.1 x 10 − 22 g. Hallar la fórmula molecular. Datos: P.A (uma): C=12, H=1
Answer:
[tex]C_{9.042}H_{17.958}[/tex]
Explanation:
(This exercise has been written in Spanish and for that reason explanation will be held in such language)
Por la definición del Número de Avogadro, un mol del compuesto contiene [tex]6.022 \times 10^{23}[/tex] moléculas. La masa de un mol se determina mediante regla de tres simple:
[tex]x = \frac{6.022\times 10^{23}\,molecules}{1\,molecule} \times (2.1\times 10^{-22}\,g)[/tex]
[tex]x = 126.462\,g[/tex]
Las participaciones másicas del carbono y el hidrógeno son, respectivamente:
[tex]m_{C} = 0.858\cdot (126.462\,g)[/tex]
[tex]m_{C} = 108.504\,g[/tex]
[tex]m_{H} = 126.462\,g - 108.504\,g[/tex]
[tex]m_{H} = 17.958\,g[/tex]
Ahora, el número de moles de cada elemento es calculado a continuación:
[tex]n_{C} = \frac{108.504\,g}{12\,\frac{g}{mol} }[/tex]
[tex]n_{C} = 9.042\,mol[/tex]
[tex]n_{H} = \frac{17.958\,g}{1\,\frac{g}{mol} }[/tex]
[tex]n_{H} = 17.958\,mol[/tex]
La fórmula molecular del hidrocarburo es:
[tex]C_{9.042}H_{17.958}[/tex]
A simple experiment to demonstrate that NaOH is a stronger alkali than NH3
Answer:
pH value test can be used to demonstrate that NaOH is a stronger alkali than NH3
Explanation:
pH value test can be used to demonstrate that NaOH is a stronger alkali than NH3. This is done by measuring the same volume of equal concentration of hydroxide and ammonia. A glass rod was dipped into 0.2 M of sodium hydroxide and 0.2 M of ammonia, each drop of solution was then placed on a pH paper matched with a color chart and the pH value was recorded.
The result showed that sodium hydroxide being a strong alkali would dissociate completely in aqueous solution thereby having a higher pH while ammonia would dissociate slightly/partially in aqueous solution thereby having a lower pH value
What is the voltage of an electrolytic cell with copper and magnesium
electrodes?
A. 2.71 V
B. -2.71 V
C. 2.03 V
D. -2.03 V
Answer:
A. 2.71 V
Explanation:
The standard reduction potential, E° of the metals are as follows:
Mg²⁺ + 2e⁻ ⇌ Mg; E° = -2.372
Cu²⁺ + 2e⁻ ⇌ Cu; E° = +0.337
Since magnesium has the the lower E°, it will serve as the anode in the electrolytic cell while copper will serve as the cathode.
At the anode; Mg ⇌ Mg²⁺ + 2e⁻, E° = -2.372
At the cathode; Cu²⁺ + 2e⁻ ⇌ Cu, E° = +0.337
EMF of the cell = E° cathode - E° anode = 0.337 - (-2.372) = 2.71 V
Therefore, EMF of the cell is 2.71 V
Answer:-2.71 is the correct answer
Explanation:
A P E X
pls help as soon I will give brainlist
Answer:
1) Conditions necessary for rusting are:
a) Presence of atmospheric oxygen or air
b)Presence of water or moisture
2) For protecting the iron gate, we can paint it because the paint will coat it and protect it from atmospheric oxygen and water.
3) Magnesium, Carbon and Oxygen (MgCO₃)
A solution has a pH of 8.4. what is the H+ concentration of the solution?
A solution has a pH of 11. What is the H+ concentration of the solution? Is the solution an acid or base?
Your father goes to the store to buy cleaner to remove such deposits from your bathtub. He has a choice between a product containing lemon juice (H+ =10^-2.5M) and one containing vinegar (H+ = 10^ -3.3M) which product would you recommend he purchase and why?
[H+]=3.98x10^-9
[H+]=10^-pH=10^-8.4
[H+]=10^-11, base
[H+]=10^-pH=10^-11
A solution with a pH of more than 7 is basic.
Lemon juice because it is more acidic
pH of lemon juice: 2.5
pH of vinegar: 3.3
Since the pH of lemon juice is lower, it is more acidic and will be more effective at removing the basic deposits.
boron has two naturally occurring isotopes .there are 10 b(20%)and 11b(80%).what is the average atomic mass of boron
Answer:
Explanation:
Average Atomic mass of any element =[ ∑ Abundance* mass of element] /100
= 10*20 +11*80 /100
= .........
Hope this helps you
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The density of water at 4.00°C is 0.967 g/mL. How many molecules of water are present in a 499.8 mL bottle of water? Express your answer to the correct number of significant figures.
Answer:
[tex]\large \boxed{1.615 \times 10^{25}\text{ molecules water}}[/tex]
Explanation:
You must calculate the mass of the water, convert it to moles, and then calculate the number of molecules.
1. Mass of water
[tex]\text{Mass } = \text{499.8 mL} \times \dfrac{\text{0.967 g}}{\text{1 mL}} = \text{483.3 g}[/tex]
2. Moles of water
[tex]\text{Moles of water} = \text{483.3 g water} \times \dfrac{\text{1 mol water}}{\text{18.02 g water}} = \text{26.82 mol water}[/tex]
3. Molecules of water
[tex]\text{No. of molecules} = \text{26.82 mol water} \times \dfrac{6.022 \times 10^{23}\text{ molecules water}}{\text{1 mol water}}\\\\= \mathbf{1.615 \times 10^{25}}\textbf{ molecules water}\\\text{The sample contains $\large \boxed{\mathbf{1.615 \times 10^{25}}\textbf{ molecules water}}$}[/tex]
The number of molecules of water present in the bottle is 1.62×10²⁵ molecules.
We'll begin by calculating the mass of the water in the bottle.
Density of water = 0.967 g/mLVolume of water = 499.8 mLMass of water =?Mass = Density × Volume
Mass of water = 0.967 × 499.8
Mass of water = 483.3066 g
Finally, we shall determine number of molecules of water in the bottle.
From Avogadro's hypothesis,
1 mole of water = 6.02×10²³ molecules
But,
1 mole of water = 18 g
Thus, we can say that:
18 g of water = 6.02×10²³ molecules
Therefore,
483.3066 g of water = (483.3066 × 6.02×10²³) / 18
483.3066 g of water = 1.62×10²⁵ molecules
Thus, the number of molecules of water in the bottle is 1.62×10²⁵ molecules.
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Diagrams, tables, and graphs are used by scientists to
Answer:
Since most of the data scientist collect is quantitative, data tables and charts are usually used to organize the information • Graphs are created from data tables • hope that helps love!
The pressure exerted by 0.002 moles of a gas in a 500 mL container at 25oC is:
Answer:
0.1715 atm
Explanation:
We use the Ideal gas equation to calculate this
Mathematically;
PV = nRT
rearranging, we have
P = nRT/V
from the question, we have
n = 0.002 moles
R = 0.082
T = 250 = 250 + 273 = 523 K
V = 500 ml = 500/1000 = 0.5 L
Plugging the values we have;
P = (0.002 * 0.082 * 523)/0.5
P = 0.1715 atm
What is the temperture at which all molecular movements stop called
Answer:
Absolute Zero
Explanation:
at 0 Kelvin, nothing can move and entropy reaches 0
Answer:
absolute zero
Explanation:
50 POINTS! Fill in the chart below to identify and describe the functional groups associated with organic chemistry.
Name General Structure Properties/Uses
Alcohol
Aldehyde
Ketone
Fatty acid
Ether
Answer:
Alcohol
Structure: Alcohols are organic molecules assembled from carbon (C), oxygen (O), and hydrogen (H) atoms.
Property: The Boiling Point of Alcohols. Alcohols generally have higher boiling points in comparison to other hydrocarbons having equal molecular masses.
Aldehyde
Structure: DescriptionAn aldehyde is a compound containing a functional group with the structure −CHO, consisting of a carbonyl centre.
Property: The polarity of the carbonyl group notably affects the physical properties of melting point and boiling point, solubility, and dipole moment.
Ketone
Structure: A ketone is a functional group with the structure RC(=O)R', where R and R' can be a variety of carbon-containing substituents.
Property: Ketones are soluble in water but their solubility decreases with increase in the length of the chain.
Fatty Acid
Structure: a fatty acid consists of a straight chain of an even number of carbon atoms, with hydrogen atoms along the length of the chain and at one end of the chain and a carboxyl group (―COOH) at the other end.
Property: Fatty acids are solid at room temperature, while unsaturated fatty acids are liquid.
Ether
Structure: a class of organic compounds characterized by an oxygen atom bonded to two alkyl or aryl groups.
Property: An ether molecule has a net dipole moment due to the polarity of C-O bonds.
The functional group associated with ethanol is -OH, the aldehyde is -COH, the ketone is -CO, the fatty acid is -COOH, and ether is ROR.
The functional groups have been the atoms that have different constituents and properties with respect to other groups.
The functional group associated with the following groups has been:
Alcohol: It has been liquid at room temperature with the functional group -OH.Aldehyde: It has been soluble in water with the functional group -COH.Ketone: It has been soluble in water, with C=O in the structure as a functional group.Fatty acid: It has been a long chain acid, with the presence of carboxylic group -COOH.Ether: It has been the pleasant smelling compounds with the presence of the R-O-R group as the functional group.
The functional group associated with ethanol is -OH, the aldehyde is -COH, the ketone is -CO, the fatty acid is -COOH, and ether is ROR.
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What is chemical potential energy?
Answer:
It is the energy that is stored in bonds that hold particles together
Explanation:
Twenty liters of NO gas react with excess oxygen. How many liters of NO2 gas are produced if the NO gas reacts completely?
Answer:
2O L
Explanation:
The balanced chemical equation is 2NO+O
2
→2NO
2
Thus, 2 moles of NO will produce 2 moles of NO
2
.
Also, the volume is directly proportional to the number of moles.
Therefore, 20 L of NO will produce 20×
2
2
=20 L of NO
2
You make an iron (II) sulfate solution with a molarity of 2.1 M. If the solution is 500 mL total, how many grams of iron (II) sulfate is that?
Answer:
Explanation:
2.1>1000
?>500
(500×2.1)÷1000=1.05moles
Mass= molesx molar mass
1.05×(56+32+(16×4))
1.05×152=159.6g
Kinetic energy definition
Answer:
kinetic energy. (General Physics) the energy of motion of a body, equal to the work it would do if it were brought to rest. The translational kinetic energy depends on motion through space, and for a rigid body of constant mass is equal to the product of half the mass times the square of the speed.
Answer:it is the simplest one
the energy possessed by a body due to its motion is called kinetic energy
K.E.=[tex]\frac{1}{2}[/tex]mv²
Which of the following statements is true?
A. Every organism is made of different elements.
B. All living things are made of the same elements.
C. Every species is made of different elements.
D. All matter is made of the same 10 elements.
Answer:
Every species is made of different elements.
Explanation:
Living organisms are classified by their species. Species refer to a group of closely related individual organisms which are callable of interbreeding with each other and exchanging genetic material.
Member of a species have similar genetic make up and often look alike, it is the lowest taxonomic rank of closely related organisms.
Members of of different species are often composed of different elements. Since individual organisms are members of a given species, we can say that every species of organisms are made up of different elements.
In which kingdom do all organisms have cells that lack a cell wall?
fungsi
plants
animals
bacteria
Answer:
The answer is animals
Explanation:
Plants and fungi have a cell wall, and although most bacteria lack a cell wall, the question is asking in which kingdom do ALL organisms lack a cell wall. Hope this helps.
Answer:Bacteria
Explanation:
Which process occurs at each link in a food chain?
Some Energy is released into the environment as heat
Explanation:
discharge by the combination of Nitrogen and oxygen
Answer:
NO2
Explanation:
N = Nitrogen
O = Oxygen
Answer:
NO. 2.
is the answer
hopes this helps
How many moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C? The freezing point depression constant for water is 1.86°C•kg/mol. What is the molality of the solution?
Answer: 1.29 moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C. Molality of solution is 1.29 m.
Explanation:
Depression in freezing point is given by:
[tex]\Delta T_f=i\times K_f\times m[/tex]
[tex]\Delta T_f=T_f^0-T_f=(0-(-2.4))^0C=2.4^0C[/tex] = Depression in freezing point
i= vant hoff factor (for non electrolyte , i = 1)
[tex]K_f[/tex] = freezing point constant for water= [tex]1.86^0C/kgmol[/tex]
m= molality =[tex]\frac{\text{moles of solute}}{\text{weight of solvent in kg}}[/tex]
m= molality =[tex]\frac{x}{1kg}[/tex]
[tex]2.4^0C=1\times 1.86^0C/kgmol\times \frac{x}{1kg}[/tex]
[tex]x=1.29[/tex]
Molality = [tex]\frac{\text{moles of solute}}{\text {weight of solvent in kg}}=\frac{1.29mol}{1kg}=1.29m[/tex]
Thus 1.29 moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C. Molality of solution is 1.29 m.
Answer:
1) C (m=T f/Kf)
2) 2.4 C
3) 1.3 m
4) 1.3 moles
Explanation:
This is correct on ed
Which one is NOT an acid?
A. H2S04 B. H2NO3 C. HCI D. NaOH
what is the best way to make a supersaturated solution?
A. cool the solution
B. Stir the solution
C. Heat the solution
D. Evaporate the solution
C.heat the solution
A student places a 12-gram cube of Ice Inside a container. After six hours, the student returns to observe the contents of the container. Which
sentence suggests that the container is an open system?
ОА
The container contains 12 grams of liquid water and no ice.
B.
The container contains 12 grams of Ice and no liquid water.
D.
The container contains 8 grams of liquid water and no ice.
The container contains 8 grams of ice and 4 grams of liquid water.
The container contains 8 grams of liquid water and 4 grams of water vapor.
E
Answer:
I think its D sorry if im wrong
Answer:i think its D
Explanation:
50cm3 of sodium hydroxide solution was titrated against a solution of sulfuric acid. The concentration of the sodium hydroxide solution was 20g/dm3. Work out the concentration of the acid in grams per litre if it took 25cm3 of acid to completely neutralise the alkali. The relative molecular mass of sulfuric acid is 98.
Answer:
49 g/L is the concentration of the acid
Explanation:
Firstly, we proceed to write the equation of reaction.
2NaOH + H2SO4 ——-> Na2SO4 + 2H2O
We can see that 1 mole of the base reacted with two moles of the acid.
kindly note that dm^3 is same as liter
Firstly, we need to get the concentration of the reacted sulphuric acid in g/L
we use the simple titration equation below;
CaVa/CbVb = Na/Nb
From the question;
Ca = ?
Va = 25 cm^3
Cb = 20 g/L
we convert this to concentration in mol/L
Mathematically, that is concentration in g/L divided by molar mass in g/mole
molar mass of NaOH = 40 g/mol
so we have; 20g/L / 40 = 0.5 mol/L
Vb = 50 cm^3
Na = 1
Nb = 2
Where C represents concentrations, V volumes and N , number of moles
Now, substitute the values;
Ca * 25/0.5 * 50 = 1/2
25Ca/25 = 0.5
So Ca = 0.5 mol/L
Now to get the concentration of H2SO4 in g/L
What we do is to multiply the concentration in mol/L by molar mass in g/mol
That would be 0.5 * 98 = 49 g/L
The concentration of the acid in grams per litre is 49g/L
From the question,
We are to determine concentration of the sodium hydroxide solution.
First, we will write a balanced chemical equation for the reaction.
The balanced chemical equation for the reaction is
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
This means,
2 moles of NaOH is required to completely neutralize 1 mole of H₂SO₄
From the formula
[tex]\frac{C_{A}V_{A} }{C_{B}V_{B} }=\frac{n_{A} }{n_{B} }[/tex]
Where
[tex]C_{A}[/tex] is the concentration of acid
[tex]C_{B}[/tex] is the concentration of base
[tex]V_{A}[/tex] is the volume of acid
[tex]V_{B}[/tex] is the volume of base
[tex]n_{A}[/tex] is the mole ratio of acid
[tex]n_{B}[/tex] is the mole ratio of base
From the question
[tex]V_{A}= 25 \ cm^{3}[/tex]
[tex]C_{B} = 20 \ g/dm^{3}[/tex]
Convert this to mol/dm³
Molar mass of NaOH = 40 g/mol
Using the formula
[tex]Concentration\ in \ mol/dm^{3} =\frac{Concentration\ in \ g/dm^{3}}{Molar\ mass}[/tex]
∴ Concentration of the NaOH in mol/dm³ = [tex]\frac{20}{40}[/tex]
Concentration of the NaOH in mol/dm³ = 0.5 mol/dm³
∴ [tex]C_{B} = 0.5 \ mol/dm^{3}[/tex]
and
[tex]V_{B} = 50 \ cm^{3}[/tex]
From the balanced chemical equation
[tex]n_{A} = 1[/tex]
[tex]n_{B} = 2[/tex]
Putting the parameters into the formula, we get
[tex]\frac{C_{A} \times 25}{0.5 \times 50}= \frac{1}{2}[/tex]
Now, this becomes
[tex]2 \times 25 \times C_{A}=0.5 \times 50 \times 1[/tex]
Then, we get
[tex]50 C_{A} = 25[/tex]
∴ [tex]C_{A} = \frac{25}{50}[/tex]
[tex]C_{A} = 0.5 \ mol/dm^{3} = 0.5 \ mol/L[/tex]
Now, we will determine the concentration in g/L
From the formula,
Concentration in g/L = Concentration in mol/L × Molar mass
From the question,
Molar mass of sulfuric acid = 98
∴ Concentration of the acid in g/L = 0.5 × 98
Concentration of the acid in g/L = 49 g/L
Hence, the concentration of the acid in grams per litre is 49g/L
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Solids, liquids and gases are the three most commonly accepted phases of matter. Explain the properties of each phase, including their relative energy.
Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the way the particles inside them differ.
In a gas, the molecules are spread wide apart and moves freely at high speeds
In a liquid, the more closer to each other and will vibrate or slip past each other
In a solid, the molecules are tightly packed, making no room for each other and harder to move. These molecules vibrate and jiggle but, don't move
Why are prefixes often added to SI units?
Answer: SI prefixes are used to form decimal multiples and submultiples of SI units. They should be used to avoid very large or very small numeric values.
Explanation: ^^^
ANSWER IT CORRECTLY PLEASE!!
The Osmotic pressure of blood is 7.65 ATM at 310 k. An aqueous solution of glucose is isotonic with blood has the percentage by volume
a.5.41%
b.3.54%
c.4.53%
d.53.4%
Answer:
Explanation:
Pv = n RT
P =7.65, T= 310K, for glucose n = moles= weight/molar mass= weight/180, R is gas constant
7.65* V =W/180 *0.0821 * 310
w/v= 7.65*180/0.0821*310 = 1377/25.45 = 54.10 =5.4%