Answer:
C) Reactants absorb a minimum amount of energy and then release a smaller
amount of energy as products form.
Explanation:
The statement that best describes how to read a reaction pathway from the graph of an endothermic reaction is that, reactants absorb a minimum amount of energy and then release a smaller amount of energy as products form.
In an endothermic change, heat is absorbed from the surrounding.
As such, the surrounding becomes colder at the end of the reaction. On a graph of an endothermic reaction, the reactants absorbs a minimum energy. As the reaction proceeds, the products gives off an even lesser amount of energy.For which of the following processes would S° be expected to be most positive? a) O2(g) + 2H2(g) 2H2O(g) b) H2O(l) H2O(s) c) NH3(g) + HCl(g) NH4Cl(g) d) 2NH4NO3(s) 2N2(g) + O2(g) + 4H2O(g) e) N2O4(g) 2NO2(g) 12. Which of the following statements is
Answer:
Explanation:
a) O₂(g) + 2H₂(g) = 2H₂O
b) H₂O(l) = H₂O(s)
c) NH₃(g) + HCl(g) = NH₄Cl(g)
d) 2NH₄NO₃(s) = 2N₂(g) + O₂(g) + 4H₂O(g)
e) N₂O₄(g) = 2NO₂(g)
ΔS is positive when there is increase in disorderliness. It happens when there is increase in volume .
Increase is volume is maximus in the following reaction.
d) 2NH₄NO₃(s) = 2N₂(g) + O₂(g) + 4H₂O(g)
in this reaction solid NH₄NO₃ is changed to 7 x 22.4 L of gases so there is maximum increase in volume . Hence maximum increase in entropy . Hence ΔS is most positive .
Which is the best surface for absorbing heat radiation? ☆ Shiny white Shiny black Dull black Dull white
Dull black surface are good absorbers of radiation.
Thermal radiationThe process by which energy in the form of electromagnetic radiation is emitted by a heated surface and travels directly to its absorption point at the speed of light.
The rate at which a body absorbs or radiates thermal radiation relies upon the nature of the surface as well.
According to the Kirchhoff's radiation law, the objects, which are good emitters are also good absorbers.
A blackened surface is an excellent absorber as well as an excellent emitter.
A black body refers to a body, which is regarded as a perfect radiator and absorber of electromagnetic radiations, a dull black surface is a good absorber of heat radiation.
Thus, dull black surface is the best surface for absorbing heat radiation.
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Potassium hydrogen phthalate is a solid, monoprotic acid frequently used in the laboratory to standardize strong base solutions. It has the unwieldy formula of KHC8H4O4. This is often written in shorthand notation as KHP.
Required:
How many grams of KHP are needed to exactly neutralize 25.6 mL of a 0.527 M potassium hydroxide solution?
Answer:
2.75 g
Explanation:
The number of moles of KOH is obtained from the equation;
n=CV
C= concentration
V= volume of solution
n= 0.527 × 25.6/1000
n= 0.0135
Reaction equation;
KOH(aq) + KHC8H4O4(aq) --->(KC8H4O4)K(aq) + H2O(l)
1 mole of KHP reacts with 1 mole of KOH
Hence; 0.0135 moles of KHP reacts with 0.0135 moles of KOH
From;
Number of moles = reacting mass/molar mass
Reacting mass = 0.0135 × 204
= 2.75 g of KHP
Mass number is equal to
(10 Points)
O neutrons and electrons
o electrons and protons
O protons and nucleus
protons and neutrons
Which of the following compounds contains polar covalent bonds?
a) CS2
b) LiF
c) F2
d) CH3F
Answer:
no d
Explanation:
it has a permanent dipole
CH₃F compound contains polar covalent bonds in its structure, hence option D is correct.
This happens when the electronegativity of the relevant atoms differs significantly.
The electronegativities of the carbon and fluorine atoms in CH3F are dissimilar. Because fluorine is more electronegative than carbon, it attracts the shared electrons to it, giving the fluorine atom a partial negative charge and the carbon atom a partial positive charge.
A polar covalent bond is created as a result of this unequal charge distribution. CH₃F compound contains polar covalent bonds in its structure.
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empirical formula of N4H8O4
Answer:
NH₂O
Explanation:
Given compound:
N₄H₈O₄
Unknown:
The empirical formula of the compound = ?
Solution:
The empirical formula of a compound is its simplest formula. It expresses the composition of a the compound in the simplest whole ratio of atoms of the different elements present in the compound.
For the given compound:
N₄H₈O₄
Number of moles of N = 4
H = 8
O = 4
the highest common factor is 4 and we simply divide through by this number;
N = 1
H = 2
O = 1
So, the empirical formula of compound is NH₂O
Cathode rays are deflected toward a negatively charged plate in an electric field.
True
False
Answer:
true. cathode rays are deflected
Substance B is hard, does not conduct electricity, and melts at 1200 °C. Substance B is likely a(n):
(a) ionic solid
(b) metallic solid
(c) molecular solid
(d) covalent network solid
Aluminum metal and bromine liquid (red) react violently to make aluminum bromide (white powder). One way to represent this equilibrium is:
Al(s) + 3/2 Br2(l)AlBr3(s)
We could also write this reaction three other ways, listed below. The equilibrium constants for all of the reactions are related. Write the equilibrium constant for each new reaction in terms of K, the equilibrium constant for the reaction above.
1) 2 AlBr3(s) 2 Al(s) + 3 Br2(l)
2) 2 Al(s) + 3 Br2(l) 2 AlBr3(s)
3) AlBr3(s) Al(s) + 3/2 Br2(l)
Answer:
Explanation:
Al(s) + 3/2 Br₂(l) = AlBr₃(s)
K = [ AlBr₃] / [ Al] [ Br₂]³/²
K² = [ AlBr₃]² / [ Al ] ² [ Br₂]³
2 AlBr₃ = 2 Al(s) + 3 Br₂(l) =
K₁ = [ Al ] ² [ Br₂]³ / [ AlBr₃]²
K₁ = ( 1 / K² ) = K⁻²
2 ) 2 Al(s) + 3 Br₂(l) = 2 AlBr₃(s)
K₂ = [ AlBr₃ ]² / [ Al ]² [ Br₂ ]³
K₂ = K²
3 )
AlBr₃(s) = Al(s) + 3/2 Br₂(l)
K₃ = [ Al ] [ Br₂ ] ³/² / [ AlBr₃ ]
= ( 1 / K ) = K⁻¹
What calculated value is used to evaluate accuracy for a set of data? Group of answer choices (multiple choice) yield percent error range
Answer:
Percent error
Explanation:
Percent error is defined as the percentage of the difference between the measured( accurate value) and the known value of a substance.
It is usually calculated by:
Measured value — Known value/ known value * 100%
Percent error is the calculated value that is used to evaluate accuracy for a set of data
What mass of water is produced from the complete combustion of 6.60×10−3 g of methane?
State the number of sig figs in each value:
1) 0.00004050
2) 54.7000
3) 1,000.09
4) 0.039
Answer:
Explanation:
Significant figure implies number of digits that are to be considered. Some rules are required to be considered when writing a given expression to an expected significant figures.
So that:
1) 0.00004050 is 4 significant figures
2) 54.7000 is 6 significant figures
3) 1,000.09 is 6 significant figures
4) 0.039 is 2 significant figures
A plant uses carbon dioxide and water to form food and oxygen. Why is this a chemical change?
Answer:
The plant uses carbon dioxide and water to make an entirely new chemical hence chemical change.
Explanation:
Plants create their own 'food', they turn carbon dioxide water and sunlight to create starch and glucose..
Answer:
The properties of carbon dioxide and oxygen are different.
Explanation:
im taking the exam right now and Im pretty sure it's D The properties of carbon dioxide and oxygen are different.
What is the amount of charge on a calcium ion if its neutral atom has lost two valence electrons?
A. 1+
B. 2+
C. 3+
D. 4+
Answer: B
Explanation: a calcium ion has a charge of +2 because it has 2 more protons than electrons giving it a positive charge instead of neutral or negative.
How are ecological islands different from geographical islands as described from the reading in the text?
Answer:
Ecological islands is just a terminology used, since it isn't surrounded by water like an actual island, instead, it's something isolated from other things, which is the same thing as an island in a way:
Island (geographical) - Land isolated from bigger "main" land masses by water.
Island (ecological) - Land which contains certain isolated features (habitat, plants, etc.).
Explanation:
An ecological island is an area of land, isolated by natural or artificial means from its surrounding land while geographical islands are a body of land surrounded by water.
What are ecological islands and geographical islands?An ecological island refers to an area of land which is not necessarily an actual island but isolated by natural or artificial means from the surrounding land. A natural micro-habitat exists on sich lands amidst a larger differing ecosystem.
In artificial ecological islands, all non-native species are eradicated, native species are reintroduced and nurtured, and the natural or artificial border is maintained to prevent the reintroduction of non-native species.
A geographical island is a body of land surrounded by water. Continents are also surrounded by water as they are so big but they are not considered islands. Islands may be categorized as either continental or oceanic.
There are so many islands in the lakes, oceans, and rivers around the world. They vary in climate, size, and the types of organisms that inhabit them.
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A student ran the following reaction in the laboratory at 751 K: N2(g) + 3H2(g) 2NH3(g) When she introduced 3.47×10-2 moles of N2(g) and 6.38×10-2 moles of H2(g) into a 1.00 liter container, she found the equilibrium concentration of H2(g) to be 6.25×10-2 M. Calculate the equilibrium constant, Kc, she obtained for this reaction.
Answer:
Kc = 4.86×10⁻⁶
Explanation:
We begin from the equation:
N₂ + 2H₂ ⇄ 2NH₃
We start from 3.47×10⁻² moles of N₂(g) and 6.38×10⁻² moles of H₂(g), so when we reach the equilibrium, we get 6.25×10⁻² moles of H₂.
This data means, that in the reaction we made react:
6.38×10⁻² - x = 6.25×10⁻²
x = 1.3×10⁻³ moles of H₂
As stoichiometry is 1:3, we will know that the moles of N₂ that have been reacted were:
1.3×10⁻³ moles / 3 = 4.33×10⁻⁴ moles of N₂
So, in the equilibrium we would have:
3.47×10⁻² moles of N₂ - 4.33×10⁻⁴ moles of N₂ = 0.0343 moles of N₂
How many ammonia, would we have in the equilibrium?
4.33×10⁻⁴ mol . 2 = 8.66×10⁻⁴ moles (from stoichiometry with N₂, 1:2)
(1.3×10⁻³ mol . 2) / 3 = 8.66×10⁻⁴ moles (from stoichiometry with H₂, 2:3)
Let's make the expression for Kc
Kc = [NH₃]³ / [N₂] . [H₂]²
(8.66×10⁻⁴ )³ / (0.0343 . (6.25×10⁻²)² = 4.86×10⁻⁶
the two stages of cellular respiration.
Which belongs in the area marked X?
Energy is released.
Oxygen is used up.
Glucose is broken down.
Carbon dioxide is used up.
Answer:
Oxygen is used up
Explanation:
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Rearange the equation to isolate a. (a+b/c)(d-e)=f find a =
Answer:
[tex]a=\frac{f}{d-e}-\frac{b}{c}[/tex]
Explanation:
Hello.
In this case, for the equation:
[tex](a+b/c)(d-e)=f[/tex]
For isolating a, we must first pass (d-e) to divide at the other side as it is initially multiplying:
[tex]a+b/c=\frac{f}{(d-e)}[/tex]
Next, as b/c is adding, it passes to subtract at the other side in order to finally isolate a:
[tex]a=\frac{f}{d-e}-\frac{b}{c}[/tex]
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Which 2 main body systems work alongside the digestive system?
Which profile best shows the topography alone line AD
How many molecules of NH3 are produced from 8.01x10-4g of H2
Answer:
1.61 x 10²⁰ molecules
Explanation:
Given parameters:
Mass of the hydrogen gas = 8.01 x 10⁻⁴g
Unknown
Number of molecules of NH₃ = ?
Solution:
Given reaction:
N₂ + 3H₂ → 2NH₃
We have to solve from the known to the unknown
The known specie is the mass of H₂ ;find the number of moles of the specie;
number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of H₂ = 2(1) = 2g/mol
Number of moles = [tex]\frac{0.0008}{2}[/tex] = 0.0004mol
3 moles of H₂ will produce 2 moles of NH₃0.0004 moles of H₂ will produce [tex]\frac{0.0004 x 2}{3}[/tex] = 0.00027moles of NH₃
1 mole of a substance contains 6.02 x 10²³ molecules
0.00027mole of NH₃ will contain 0.00027 x 6.02 x 10²³
= 1.61 x 10²⁰ molecules
.
Can you explain why you feel warm when you are standing near a campfire?
Answer:
You feel warm when you stand near a campfire because the flames of the fire warm your body. The heated waves are hit towards you and your body feels warm.
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Explanation:
Which of the following is an example of a chemical change that occurs in your home?
A) Water boiling on the stove
B) Composting your own fertilizer
C) Smashing a window with a baseball
D) Adding food coloring to icing for a cake
The atomic notation for a particular atom of boron is ' B. The
atomic number is while the mass number is
Answer:
5;11
Explanation:
You have a 50.0g samples of silver, a 50g sample of iron, and a 50g sample of water. You add 100 J of energy to each sample. Which substance will have the largest resulting temperature change? Which substance will have the smallest temperature change?
Answer:
Silver.
Explanation:
Hello!
In this case, we can consider the specific heat as the property that we can analyze in order to answer to this question. In such a way, as the specific heat is known as the energy required to modify the temperature of 1 g of the substance by 1 °C, since the masses of all the substances are the same, we can that their specific heats are respectively 0.240, 0.444 and 4.184 J/(g°C), from the equation:
[tex]Q=mCp\Delta T[/tex]
We can see that the higher the specific heat (Cp) the lower the change in temperature considering their inversely proportional relationship. However, as 100 J of energy is applied to all the substances, we can see that silver will exhibit the largest temperature change because a higher change is needed to fit with the provided energy.
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Compare ionic, covalent, and metallic bonds based on each's strength
Answer:
Covalent bond involves the sharing of electrons, while metallic bonds have strong attractions and ionic bonds involve the transferring and accepting of electrons from the valence shell. The adhering property of an atom, in order to arrange themselves in a most stable pattern by filling their outermost electrons orbit
Explanation:
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MY ELEMENT IS NICKEL!!
Answer:
Metallurgy can be isolate other elements. Iron and bronze are the common metalsNickel is the metal which reacts with many metalsSome halogen and discredited metalsFind the density of a liquid that has a mass of 24 grams and a volume of 6 ml.
Answer:
4
Explanation:
24/6 is 4.
Answer:
Mathematically: D = m/v. If you know what liquid you have, you can look up its density in a table. Once you know that, all you have to do to find the mass of the liquid is to measure its volume. Once you know density and volume, calculate mass using this relationship: mass = density • volume.
Explanation:
Determine each type of reaction. 2 C 2 H 2 ( g ) + 5 O 2 ( g ) ⟶ 4 C O 2 ( g ) + 2 H 2 O ( l ) 2CX2HX2(g)+5OX2(g)⟶4COX2(g)+2HX2O(l) Choose... N H 4 N O 3 ( s ) ⟶ N 2 O ( g ) + 2 H 2 O ( l ) NHX4NOX3(s)⟶NX2O(g)+2HX2O(l) Choose... C O ( g ) + 2 H 2 ( g ) ⟶ C H 3 O H ( l ) CO(g)+2HX2(g)⟶CHX3OH(l) Choose... 2 F e ( s ) + 6 H C l ( a q ) ⟶ 2 F e C l 3 ( a q ) + 3 H 2 ( g ) 2Fe(s)+6HCl(aq)⟶2FeClX3(aq)+3HX2(g) Choose... C a C l 2 ( a q ) + N a 2 C O 3 ( a q ) ⟶ 2 N a C l ( a q ) + C a C O 3 ( s ) CaClX2(aq)+NaX2COX3(aq)⟶2NaCl(aq)+CaCOX3(s) Choose...
Answer:
2 C 2 H 2 ( g ) + 5 O 2 ( g ) ⟶ 4 C O 2 ( g ) + 2 H 2 O ( l )- combustion reaction
N H 4 N O 3 ( s ) ⟶ N 2 O ( g ) + 2 H 2 O ( l )- decomposition reaction
C O ( g ) + 2 H 2 ( g ) ⟶ C H 3 O H ( l ) - combination reaction
2 F e ( s ) + 6 H C l ( a q ) ⟶ 2 F e C l 3 ( a q ) + 3 H 2 ( g )- Redox reaction
C a C l 2 ( a q ) + N a 2 C O 3 ( a q ) ⟶ 2 N a C l ( a q ) + C a C O 3 ( s )- double displacement reaction
Explanation:
We can determine the type of reaction by considering the reactants and products.
Combustion is a reaction between a substance and oxygen which produces heat and light. The first reaction is the equation for the combustion of ethyne.
A decomposition reaction is one in which a single reactant breaks down to form products. The second reaction is the decomposition of ammonium nitrate.
A combination reaction is said to occur when two elements or compounds react to form a single product. The third reaction is the combination of carbon dioxide and methane to form methanol.
An oxidation-reduction reaction is a reaction in which there is a change in oxidation number of species from left to right of the chemical reaction equation. The fourth reaction is the oxidation of iron (0 to +3 state) and reduction of hydrogen (+1 to 0 state).
A double displacement reaction is a reaction in which ions exchange partners from left to right in the reaction equation. The fifth reaction is a double displacement reaction. Both Na^+ and Ca^2+ exchanged partners from left to right of the reaction equation.
Reactions are the formation of the products from the reactant. The types of reactions are combustion, decomposition, combination, Redox and double displacement.
What are the types of reactions?The reaction is a chemical change in the properties of the reactant that forms the products. It can be of various types based on the formation of the product.
The first reaction is combustion as the reactants react and use oxygen to form heat, carbon dioxide and water. The combustion reaction of ethyne can be shown as,
[tex]\rm 2 C _{2} H _{2} ( g ) + 5 O _{2} ( g ) \rightarrow 4 C O _{2} ( g ) + 2 H _{2} O ( l )[/tex]
The second reaction is decomposition in which a single reactant decomposes to form two or more products. The decomposition of ammonium nitrate can be shown as,
[tex]\rm N H _{4} N O _{3} ( s ) \rightarrow N _{2} O ( g ) + 2 H _{2} O ( l )[/tex]
The third reaction is a combination reaction in which two compound or elements combines to form one product. The combination reaction between carbon monoxide and hydrogen to form methanol can be shown as,
[tex]\rm C O ( g ) + 2 H _{2} ( g ) \rightarrow C H _{3} O H ( l )[/tex]
The fourth reaction is redox and includes the oxidation and the reduction of the species of the reaction. In the reaction, iron undergoes oxidation and hydrogen reduction. The redox reaction can be shown as,
[tex]\rm 2 F e ( s ) + 6 H C l ( a q ) \rightarrow 2 F e C l _{3} ( a q ) + 3 H _{2} ( g )[/tex]
The fifth reaction is a double displacement reaction in which the calcium and sodium interchange their position in the product formation. The reaction can be shown as,
[tex]\rm C a C l _{2} ( a q ) + N a _{2} C O _{3} ( a q ) \rightarrow 2 N a C l ( a q ) + C a C O _{3} ( s )[/tex]
Therefore, the type of reactions is 1. combustion, 2. decomposition, 3. combination, 4. redox and 5. double displacement.
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True or false this model represents an ion
Answer:
False
Explanation:
From the question given above, the following data were obtained:
Electron number = 6
Proton number = 6
Neutron number = 6
From the question given above, we can see clearly that the model has the same number of protons and electrons. Hence the model is not an ion.
This can further be explained if we determine the charge.
Electron number = 6
Proton number = 6
Charge =?
Charge = Proton – Electron
Charge = 6 – 6
Charge = 0
Since the charge is zero, the model is not an ion.