Final answer:
STP for thermochemical equations is 273.15 K and 1 bar, previously it was 1 atm. It serves as a reference for reporting thermodynamic properties.
Explanation:
The standard conditions of temperature and pressure (STP) for a thermochemical equation are defined as a temperature of 273.15 K (0°C) and a pressure of 1 bar (100 kPa). It is important to note that previously, the old definition used a standard pressure of 1 atm. Under these conditions, we can calculate properties of gases and thermochemical data such as enthalpies of formation. For species in solution, the standard condition is a concentration of 1 Molar (1 mol/L). Pure substances are considered in their most stable form at 1 atm and at the standard temperature, unless otherwise noted in a specific text.
Significance of STP in Thermochemical Equations
The significance of STP in thermochemical equations lies in its use as a benchmark for reporting the thermodynamic properties of substances. This consistent baseline allows for the comparison and understanding of data, such as enthalpies of formation, which are essential for studying chemical reactions and processes.
The answer is option A - 0°C and 101 kPa. Standard conditions of temperature and pressure for a thermochemical equation are 0°C and 101 kPa.
Standard conditions of temperature and pressure (STP) for thermochemical equations are 0°C and 101 kPa, equating to 0°C (273.15 K) and 1 bar (100 kPa). This set of conditions is referred to as standard temperature and pressure (STP), which is defined as 0°C (273.15 K) and 1 bar (100 kPa). However, it's important to note that there have been different definitions over time, with an older definition using 1 atm (101.325 kPa) instead. For most thermochemical data and calculations, STP is used as a reference point to enable comparisons of the properties of different gases.
The question is:
Standard conditions of temperature and pressure for a thermochemical equation are _____.
A. 0°C and 101 kPa.
B. 25°C and 101 kPa.
C. 0°C and 0 kPa.
D. 25°C and 22.4 kPa.
A 1.0 g sample of hydrogen reacts completely with 19.0 g of fluorine to form a compound of
hydrogen and fluorine. What is the percent composition by mass of hydrogen in this
compound?
Answer: hydrogen has 0.0504% and Fluorine has 0.950%
Explanation: H= 1.00794
F= 18.9984
1 X 1.00794+ 1 X 18.9984= 20.00778g/mol
H= 1.00794/20.00778= 0.0504%
F-18.9984/20.00778= 0.950%
Name two nineteenth century scientists—one who developed the laboratory burner
in common use today, and the other who studied the spectra of colored flames
produced by a variety of elements.
Answer:
1. Robert Bunsen hence being called the bunsen burner. 2. William Kirchhoff
Explanation:
Newton's Laws of Motion
Please please I need this is very urgent please respond in a mess than five minutes I need this look at the image above for the questions
Please help?!??!!
Worth 50 points?!!!!?!!!!!!!
Answer:
a: 1st paragraph from the left side indicates Newton's first law.
b:, 2nd paragraph from the left side indicates Newton's third law.
c: 1st paragraph from right side indicates Newton's first law.
d: 2nd paragraph from right side indicates Newton's second law.
Explanation:
What is quantum model of the atom often called.
Answer:
Quantum mechanics or physics
Explanation:
isotopes of the same element must also have the same?
a) number of alpha particles
b) average mass number
c) atomic number
d) number of neutrons
Answer:
The correct answer is c atomic number
Explanation:
When two atoms contain same atomic number or proton number then these two atoms are called isotopes of each other.
For example protium and tritium are isotopes of each other as they contain same atomic number that is 1.
How many moles of magnesium are 5.231 X 1023 atoms of magnesium?
Answer:
0.87 moles
Explanation:
Given data:
Number of moles of magnesium = ?
Number of atoms of magnesium = 5.23 × 10²³ atoms
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
one mole = 6.022 × 10²³ atoms
5.23 × 10²³ atoms × 1 mol / 6.022 × 10²³ atoms
0.87 moles
How is a chemical equation used to represent a chemical reaction?
1. The atoms on the left side of the arrow are different from the atoms on the right, but are arranged similarly.
2. The atoms on the left side of the arrow are different from the atoms on the right, and are arranged differently.
3. The atoms on the left side of the arrow are the same as the atoms on the right, but are arranged differently.
4. The atoms on the left side of the arrow are the same as the atoms on the right, and are arranged the same.
Answer:
3. The atoms on the left side of the arrow are the same as the atoms on the right, but are arranged differently.
Explanation:
A chemical reaction is represented by a chemical equation which show the reactant and products. Reactants are written on left side of arrow while products are written on right side. The number of atoms are remain same however arrangement of atoms is different on both side.
For example:
6H₂O + 6CO₂ + energy → C₆H₁₂O₆ + 6O₂
it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen. The number of atoms are same on both side however arrangement of atoms is different.
2. I'm strong and stiff. Getting through me is TOUGH! I'm found only in plants and I guess that's
enough
Answer:
This is called a "cell wall'.
Explanation:
Answer: cell wall
Explanation:
Which of the following substances can be classified as a salt?
A.
Sodium Chloride (NaCl)
B.
Vinegar (CH3COOH)
C.
Baking Soda (NaHCO3)
D.
Bleach (NaClO)
Sodium Chloride (NaCl) can be classified as a salt
Explanation:
Sodium chloride is an "ionic compound" is known as salt. The ratio in which the sodium(Na) and chloride(Cl) present in sodium chloride in NaCl is 1:1. It is found in seawater and is accountable for the salinity of the seawater. Also, NaCl is the extracellular fluid for various multicellular organisms.
When refined, it becomes in its 'edible' form and is used in food preservatives. Whereas, the large quantity of sodium chloride is used in various industries.
Water exist as a liquid between 0 and 100 Celsius.
a. True
b. False
a. True. Water exists as a liquid between 0 and 100 degrees Celsius.
Freezing Point: Water freezes at 0 degrees Celsius (32 degrees Fahrenheit). This is the temperature at which water starts to change from a liquid to a solid (ice) under normal atmospheric pressure.
Boiling Point: Boiling point of water is 100 degrees Celsius (212 degrees Fahrenheit). This is the temperature at which water changes from a liquid to a gas (steam) under normal atmospheric pressure.
What is the oxidation half-reaction for iron?
Answer:
Fe → Fe⁺³ + 3e⁻
Explanation:
The oxidation half reaction for iron is:
Fe → Fe⁺³ + 3e⁻
Other options are incorrect because,
A) 3e⁻ + Fe → Fe³⁺
This is incorrect because when three electrons are gained by any atom it will gain negative three charge not positive.
C) 6e⁻ + 2Fe → 2Fe³⁺
This is incorrect because when six electrons are gained by any atom it will gain negative six charge not positive.
d) Fe → 2Fe³⁺ + 6e⁻
Its also incorrect because iron atoms are not balanced on both side of equation.
An insect population increases and then decreases as the food supply changes.
Which activity does this demonstrate?
self-regulation
uncontrolled population explosion
self-restoration
unchecked exponential growth
plz help i dont understand.. T.T
Answer:
self regulation
Explanation:
Answer:
A) Self-regulation
Explanation:
A self-regulated organism takes measures to balance its own survival with the scarce resources that the enviroment offers. In this case, the insect population is self-regulating because it is responding to changes in the food supply, and adapts itself accordingly.
In a way, self-regulation is like supply and demand. As supply of food decreases, but demand stays the same, scarcity ensues. This causes the need to reduce demand until a new equilibrium is reached, where demand and supply are equal.
reactivity is the ability of matter to combine chemically with other substances true or false
Answer:True?!
Explanation:
Can someone answer this please I will fix it tomorrow if i remember
Answer:
true
Explanation:
A compound is found to be 3 percent hydrogen, 32 percent phosphorus, and 65 percent oxygen. What is the empirical formula of this compound?
HPO
HPO4
H(PO4)3
H3PO4
Answer:
Empirical formula is H₃PO₄
Explanation:
Given data:
Percentage of hydrogen = 3%
Percentage of P = 32%
Percentage of oxygen = 65%
Empirical formula = ?
Solution:
Number of gram atoms of H = 3 / 1= 3
Number of gram atoms of O = 65 / 16 = 4.06
Number of gram atoms of P = 32 / 31 = 1.03
Atomic ratio:
H : P : O
3/1.03 : 1.03/1.03 : 4.06/1.03
3 : 1 : 4
H : P : O = 3 : 1 : 4
Empirical formula is H₃PO₄.
Consider the following intermediate chemical equations.
What is the enthalpy of the overall chemical reaction?
-999 kJ
-250. kJ
250. kJ
999 kJ
Answer:
999 kJ
Explanation:
Given are two reactions with enthalpies Δ[tex]H_1=-2,439\ kJ[/tex] and Δ[tex]H_2=3,438\ kJ[/tex]
We know enthalpy is an additive property.
Thus the overall chemical equation can be obtained from adding both the two elementary equations.
Therefore the overall enthalpy is the summation of enthalphy change in each equation.
Δ[tex]H_{overall} =[/tex]Δ[tex]H_1+[/tex]Δ[tex]H_2[/tex]
Δ[tex]H_{overall}[/tex] [tex]=-2,439+3,438=999\ kJ[/tex]
Therefore the overall enthalpy is 999 kJ.
Answer: D
Explanation:
just took it
At which location in Earth's interior exhibits a change in
the trend?
inner core
outer core
lower mantle
upper mantle
Answer:Convection powers the motion of the molten outer core. The hot liquid from deep inside rises toward the cooler top of the core. The movement transfers heat upward and causes a convective flow. Cooler liquid from near the core-mantle boundary sinks downward and thus also helps to power the convection.the outer core
Explanation:
Answer:
its b
Explanation:
i took the test :)
10. What mass of glass (Cp = 0.749 J/gºC) is needed to absorb 5.00x104 J of heat, if it starts at 26.0 C and has a final temperature of 275.0°C?
Answer:
m = 0.03 × 10⁴ g
Explanation:
Given data:
Specific heat capacity = 0.749 j/g.°C
Heat absorbed = 5.0 × 10⁴ J
Initial temperature = 26.0 °C
Final temperature = 275.0 °C
Mass = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = T2-T1
ΔT = 275.0 °C - 26.0 °C
ΔT = 249 °C
Q = m.c. ΔT
m = Q / c. ΔT
m = 5.0 × 10⁴ J / 0.749 j/g.°C × 249 °C
m = 5.0 × 10⁴ J / 186.5 j/g
m = 0.03 × 10⁴ g
The mass of glass required to absorb 5.00x10⁴ J of heat with a temperature change from 26.0°C to 275.0°C, using a specific heat capacity of 0.749 J/g°C, is approximately 268 grams.
We can use the formula for heat absorption:
[tex]q = m \times C_p \times \Delta T[/tex]
where:
q is the heat absorbed (5.00x10⁴ J)m is the mass of the glassCp is the specific heat capacity (0.749 J/g°C)ΔT is the change in temperature ( [tex]275.0 \textdegree C - 26.0 \textdegree C = 249.0 \textdegree C[/tex])Let's rearrange the formula to solve for m:
[tex]m = q / (C_p \times \Delta T)[/tex]
Substituting in the given values:
[tex]m = 5.00 \times 10^4 J / (0.749 J/g \textdegree C \times 249.0 \textdegree C)[/tex]
Simplifying the calculation:
[tex]m = \frac {5.00 \times 10^4 J}{ 186.501 J/g} = 268 g[/tex]
So, the mass of the glass needed to absorb 5.00x10⁴ J of heat, with the given temperature change, is approximately 268 grams.
Sunita carries out an experiment to investigate diffusion. She uses water and a food dye to find out how the volume of water used affects the time the dye takes to spread evenly through the water. Her prediction is that the more water she uses, the longer the time needed for the dye to spread through it. Which variable will she change?
Answer:
Sunita will change the variable water.
Explanation:
Sunita have to change the variable water to perform this experiment of diffusion.This is because she is going to predict that more water she uses longer the time needed for the dye to spread through it.
As a result she is increasing the amount of water to observe the effect of diffusible substance on diffusion with time.
A student was given two clear liquids; a colorless liquid and a dark-blue liquid. The student was asked to combine the liquids in a beaker and record observations. Which of the following results, if true, would provide the best evidence that a chemical change took place when the liquids were combined
1The resulting mixture was cloudy.
2The total volume of the mixture was equal to the sum of the initial volumes.
3The resulting liquid was light blue.
4The liquids formed two separate layers in the beaker.
Answer:
1. The resulting mixture was cloudy.
Explanation:
There are 5 observations that can be observed when a chemical change takes place:
1. Color change.
2. Temperature change.
3. Formation of precipitate.
4. Production of gas.
5. Light Emission.
1st option clearly implies that a precipitate has been formed, which according to the 3rd point as mentioned above is an evidence of a chemical change.
3rd option shows a color change but is not the best evidence because it might also be that dilution has taken place, which isn't a chemical change. Hence, it isn't the best evidence.
Therefore, 1st option is the best choice.
3 The resulting liquid was light blue.
Of the ten characteristics of chemical reactions, the occurrence of color changes is the characteristic that is most easily seen and known quickly, so the third choice is the most appropriate answer.
Further Explanation
Chemical changes are changes in a substance or material that causes the formation of new substances. The characteristics of chemical change are: new types of substances are formed, substances that change cannot return to their original form, followed by changes in chemical properties through chemical reactions. During chemical changes, the mass of the substance before the reaction is the same as the mass of the substance after the reaction.
Different chemical reactions are used together in chemical synthesis to produce the desired compound product. In biochemistry, a series of chemical reactions are catalyzed by enzymes to form metabolic pathways, where synthesis and decomposition that are normally not possible in cells are carried out.
Chemical properties are properties for which chemical changes are needed.
The nature of matter tends to carry out chemical reactions, including:
Limitation Power of Ionization Reactivity Solubility Bias / can not rot
Characteristics of Chemical Reactions
Here are ten characteristics of chemical reactions that are most easily observed.
Gas bubble formation. Sediment formation. Discoloration. Temperature change. Light Emitting. Volume Change Occurs. Changes in Conductivity. Odor changes occur. Taste change. There was a change in Boiling Point and Freezing Point.
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Grade: Middle School
Subject: Chemistry
keywords: Chemical changes, characteristics of chemical reactions
If MnSO4 → MnO+SO3 is not a synthesis reaction, then what type of reaction is it?
single-displacement
decomposition
combustion
double-displacement
Answer: It would be decomposition :)
Answer:
MnSO₄ → MnO+SO₃ is a decomposition reaction.
Explanation:
In a decomposition reaction, a single substance breaks down or breaks down, producing two or more different substances. In other words, decomposition reactions are those that form two or more substances from a compound. In this reaction the atoms that form a compound are separated to give the products according to the formula:
AB → A + B
This type of reactions can occur spontaneously or caused by certain external factors, such as heat, that promote the breakdown of the molecule into simpler substances.
There are 3 types of decomposition reactions, depending on the external factor that causes the reaction:
If the decomposition is caused by a catalyst, it is called catalysis. If the decomposition occurs by the application of heat it is called thermal decomposition. If the decomposition is produced by the application of electric current, it is called electrolytic decomposition or electrolysis.Then MnSO₄ → MnO+SO₃ is a decomposition reaction.
in rutherfords experiment why were some particles deflected a small amount
Answer:
The charges repel each other
Explanation:
State the number one way of increasing the solubility of a substance and explain why it has that effect. Also, explain two ways that you can increase the rate of dissolving for substance.
Answer:
The solubility of a substance can be increased by increasing the amount of solvent in a solution.
Explanation:
Two ways by which the rate of dissolving for substance can be increased.
1 By increasing the temperature of the solution: Increase in temperature will in turn increase the entropy or disorder or randomness of the solute molecules in a solution thus increasing the rate of dissolving the substance in that solution.
2 By increasing the volume of the solution : increase in the volume of the solution by adding more solvent can also increase the dissolving rate of a specific substance in a solution.
Write a method that could be used to produce pure crystals of copper chloride from copper oxide and hydrochloric acid.
-Describe how you would make the salt from the reactants.
-Describe how you would purify the salt from the reaction mixture.
- Describe how you would make the salt from the reactants.
CuO + 2 HCl → CuCl₂ + H₂O
- Describe how you would purify the salt from the reaction mixture.
Filter the solution and let the product crystallize.
Explanation:
The reaction between copper oxide (CuO) and hydrochloric acid (HCl) will produce copper chloride (CuCl₂) and water:
CuO + 2 HCl → CuCl₂ + H₂O
-Describe how you would make the salt from the reactants
In a beaker which contain cooper oxide add the hydrochloric acid. To avoid working with concentrated hydrochloric acid, the acid may be diluted with water but make sure the add the stoechiometric amount (and a little bit of excess) in respect with the copper oxide.
-Describe how you would purify the salt from the reaction mixture.
Let the reaction proceed and then filter the solution to remove the unreacted cooper oxide.
Let the filtered solution, which contain copper chloride, water and unreacted hydrochloric acid, to stand undisturbed for several days. You may see the crystals growing from the solution. To speed up the process you may reduce the temperature.
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To produce pure crystals of copper chloride, react copper oxide with hydrochloric acid to form copper chloride and water, then purify by filtration and evaporation to obtain copper chloride crystals.
Explanation:To produce pure crystals of copper chloride from copper oxide and hydrochloric acid, the reaction involves a simple acid-base reaction, following the general word equation: acid + metal oxide → salt + water. First, copper oxide would react with hydrochloric acid to form copper chloride and water. This reaction can be represented by the equation CuO(s) + 2HCl(aq) → CuCl2(aq) + H2O(l).
To purify the copper chloride, the resulting mixture would need to be filtered to remove any unreacted copper oxide. Then, the copper chloride solution would be evaporated to obtain the crystals. This evaporation could either be done by gently heating the solution to accelerate the process or by allowing the water to evaporate naturally over time.
how many d electrons are found in cobalt
Answer:
7
Explanation:
Because cobalt's a transition metal, the 7 'd'-type electrons can count as valence electrons, though they rarely react with anything.
Determine the type of reaction: H2O + C16H17NaO14 = CO2 + H20 + C2H3NaO3?
A.) Synthesis
B.) Decomposition
C.) Single Replacement
D.) Double Replacement
Answer:
c
Explanation:
Answer:
The correct option is B) Decomposition.
Explanation:
In a decomposition reaction, a single substance decomposes, producing two or more different substances. That is, two or more substances are formed in this type of reactions from a compound. The atoms that form a compound are separated to give the products according to the formula:
AB → A + B
There are 3 types of decomposition reactions, depending on the external factor that can promote the decomposition of the molecule into simpler substances:
Catalysis: Decomposition is caused by a catalyst.Thermal decomposition: Decomposition occurs by the application of heat .Electrolytic decomposition or electrolysis: The decomposition is produced by the application of electric current.In this case a decomposition reaction occurs, where C₁₆H₁₇NaO₁₄ decomposes to give carbon dioxide (CO₂) and C₂H₃NaO₃.
Another option may have been chemical synthesis, which involves the combination of two or more substances and results in the formation of a substance. But in this case you can see that the water does not react (it appears in the reagents and in the products). This means that it helps with the decomposition mentioned previously.
So, the correct option is B) Decomposition.
As the ball falls, its energy will decrease and its energy will increase
Answer: As an object falls its potential energy decreases, while its kinetic energy increases. The decrease in potential energy is exactly equal to the increase in kinetic energy.
Explanation:
For each of the four single-displacement reactions, describe what happened in rachel well. if a chemical reaction occured, write a balanced equation for it. Then using the A, B symbols, write a general equation for a single-displacement reaction.
Answer:
Explanation:
Single replacement:
It is the reaction in which one elements replace the other element in compound.
General equation:
AB + C → AC + B
1) zinc and Copper sulfate
Zn + CuSO₄ → ZnSO₄ + Cu
Zinc is more reactive than copper it displaces the copper from copper sulfate and form zinc sulfate.
2) Aluminium and Copper sulfate
2Al + 3CuSO₄ → Al₂(SO₄)₃ + 3Cu
Aluminium is more reactive than copper it displaces the copper from copper sulfate and form aluminium sulfate.
3) Zinc and silver nitrate
Zn + 2AgNO₃ → Zn(NO₃)₂ + 2Ag
zinc is more reactive than silver it displaces the silver from silver nitrate and form zinc nitrate.
4) copper and silver nitrate
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
copper is more reactive than silver it displaces the silver from silver nitrate and form copper nitrate.
Final answer:
In a single-displacement reaction, one element replaces another element in a compound. The general equation for a single-displacement reaction is A + BC → AC + B.
Explanation:
In a single-displacement reaction, one element replaces another element in a compound. These reactions occur when a more reactive element displaces a less reactive element from its compound.
For example, in the reaction F2 + FeI3, fluorine (F2) replaces iodine (I) in the compound FeI3, resulting in the formation of FeF3:
2F2 + FeI3 → 2FeF3 + 3I2
The general equation for a single-displacement reaction can be written as A + BC → AC + B, where A is the more reactive element that displaces B from its compound BC.
4. Indicate the ionic equation, the net-ionic equation, and the spectator ions of the following
molecular equation.
HCl(aq)
+
Fe2O3(s)
→
FeCl3(aq)
+
H2O(1)
Answer:
Explanation:
Chemical equation:
HCl + Fe₂O₃ → FeCl₃ + H₂O
Balanced Chemical equation:
6HCl (aq)+ Fe₂O₃(s) → 2FeCl₃(aq) + 3H₂O(l)
Ionic equation:
6H⁺(aq) + 6Cl⁻(aq) + 2Fe⁺³(aq) + 3O²⁻(aq) → 2Fe⁺³(aq) + 6Cl⁻(aq) + 3H₂O(l)
Net ionic equation:
6H⁺(aq) + 3O²⁻(aq) → 3H₂O(l)
The Cl⁻(aq) and Fe⁺³(aq) are spectator ions that's why these are not written in net ionic equation. The water can not be splitted into ions because it is present in liquid form.
Spectator ions:
These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.
What is an oxidizing agent?
O
A. A substance that oxidizes another substance
O
B. A substance that is oxidized in a reaction
O
C. A substance that reduces another substance
O
D. The product of an oxidation reaction
SUBN
Answer:
A.) A substance that oxidizes another substance
Explanation:
An oxidizing agent always oxidize another substance by either accept electron, removing electronegative elements or adding electropositive elements to the substance.
4. Why do elements in the same family generally have similar properties?
Elements in the same family have similar properties because they share the same number and distribution of valence electrons, leading to similar chemical behaviors. Group patterns like the alkali metals in Group 1A with one valence electron contribute to these predictable reactivity patterns. Trends, such as increasing metallic character down a group, are also observed.
Elements in the same family or group of the periodic table generally have similar properties because they have the same number and distribution of electrons in their valence shells. This similarity in electron configuration explains their comparable chemical behaviors. For instance, all elements in Group 1A have one valence electron, which leads to common reactivity patterns and they are known as the alkali metals. As we progress along a group, there are also trends, such as an increase in metallic character from nonmetals like oxygen to metals like polonium.
In the 19th century discoveries, similar compounds formed by the reactions of elements such as lithium, sodium, and potassium with other elements underscored the pattern of similar chemical properties within a group. The figure from the provided reference indicates that within a group, elements have the same s and p valence electron configurations, which play a crucial role in their reactions and interactions.
Therefore, the periodic table is deliberately structured to group elements with similar properties, following the patterns of electron configurations, specifically within their valence shells, resulting in the elements' predictable chemical behavior. This order mirrors the sequential filling of electron subshells, ensuring that elements in a family react similarly in chemical reactions.