Option B is the correct answer. The best title for these notes is theories.
An explanation for an event in the natural world or the cosmos that has passed rigorous testing and verification using accepted techniques for observation, measurement, and result evaluation is referred to as a scientific theory.
A scientific theory is different from a scientific fact or law in that it explains "why" or "how." Newton's Law of Gravity, for instance, is a mathematical formula that can be used to forecast the attraction between bodies but is not a theory that explains how gravity operates.
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Answer:
B
Explanation:
4 Fe(s) + 3 O2(g) → 2 Fe2O3(s) How many grams of oxygen gas, O2(g), are needed to react completely with 17.86 grams of iron?
• According to the balanced equation, we have :
4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)
4 x 55.85g of Fe reacts with 3 x 32g of Oxygen
Given 17.86 g of Ion, we want to find out how much oxygen will be required in this instance .
• So :
M.mass Fe: 4* 55.85 = 223.4
M.mass O2 : 3* 32 = 96
we can rearrange by :
223.4 → 96
17.86 → x .....(cross multiply )
223.4x = 96* 17.86
x = (96 *17.86) / 234.4
x = 7.314
• Therefore mass of oxygen required = 7.3g ,
What is the standard cell notation for an electrolytic cell with aluminum and gold electrodes? (answer choices in screenshot)
Oxidation takes place at the anode. Reduction takes place at the cathode. Oxidation takes place on the left and recution takes place on the right.
The standard cell notation for an electrolytic cell with alumium and gold electrodes:
[tex]Al(s)\lbrack Al^{3+}(aq)\parallel Au^+(aq)]Au(s)[/tex]To determine which metal undergoes oxidation and which undergoes reduction we use the standard cell potentetial of the metals. Au is the stronger oxidising agent of the two and so it is likely to undergo reduction and so the Al will undergo oxidation.
Answer: A
Imagine the movement of gas particles in a closed container. According to the kinetic molecular theory, which statements below are true of the gas particles? Check all that apply.
Based on the kinetic molecular theory, the statements that are true of the gas particles are as follows:
Gas particles act like tiny, solid spheres; option A.Gas particles are in constant, random motion; option BCollisions are elastic, there is no energy lost as the particle hits the sides of the container; option C.What is the kinetic molecular theory?The Kinetic Molecular Theory is the theory that molecules of a gas are in constant random motion colliding with one another and with the wall of their container.
These collisions between the gas molecules are perfectly elastic and are responsible for the pressure of gas molecules.
The higher the kinetic energy of the gas molecules, the higher the temperature of the gas.
The kinetic molecular theory explains the physical state of gases since gas molecules have negligible intermolecular forces.
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Complete question:
Imagine the movement of gas particles in a closed container. According to the kinetic molecular theory, which statements below are true of the gas particles? Check all that apply. Gas particles act like tiny, solid spheres. Gas particles are in constant, random motion. Gas particles at lower temperatures move faster. Collisions are elastic, there is no energy lost as the particle hits the sides of the container. Slower moving particles collide more often and with more force with the container.
30.Which of the following procedures increases the amount of oxygen that is dissolved in a certain amount of water?Select one:a. Increasing the air pressure on the solution.b. Shaking the solution.c. Stirring the solution.d. Warming the solution.
Answer
a. Increasing the air pressure on the solution.
Explanation
Measurements show that the energy of a mixture of gaseous reactants decreases by 181.kj during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -86.kj of work is done on the mixture during the reaction.
Calculate the change in enthalpy of the gas mixture during the reaction. Round your answer to 2 significant digits.
The change in enthalpy of the gas mixture during the reaction is - 95 kj.
The formula for the change in internal energy is given by:
ΔU = ΔH + W
ΔU = the change in inter energy = -181 kj ( decreased)
ΔH = the change in enthalpy
W = work done = -86 kj
substituting the values in the formula we get :
ΔU = ΔH + W
- 181 kj = ΔH - 86 kj
ΔH = -181 kj + 86 kj
ΔH = - 95 kj
Measurements show that the energy of a mixture of gaseous reactants decreases by 181.kj during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -86.kj of work is done on the mixture during the reaction. The change in enthalpy of the gas mixture during the reaction is - 95 kj.
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1. What is the difference between a homogenous and a heterogeneous mixture? 2. Give 3 examples of each mixture and explain its uses in our daily lives.
Answer:By combining two or more substances, a mixture is produced. A homogeneous solution tends to be identical, no matter how you sample it. Homogeneous mixtures are sources of water, saline solution, some alloys, and bitumen. Sand, oil and water, and chicken noodle soup are examples of heterogeneous mixtures.
Explanation:
HELP ASAP 50 POINTS WILL MARK BRAINLY REAL ANSERS ONLY
Answer:A
Explanation:because i did the test
Component Q is more powerful in explaining a scientific phenomenon because peer conformation and support are characteristics of a theory.
Scientific phenomena are events that can be witnessed in the natural and artificial worlds that make people wonder and pose questions. A theory is a logical interpretation or explanation of a phenomenon or set of occurrences. For instance, the theory of evolution through natural selection is a hypothesis because it explains the variety of life on earth.
In addition to offering accurate explanations or interpretations, theories also serve additional objectives. Here, we examine three additional goals of theories: the organizing of well-understood phenomena, the forecasting of outcomes in novel circumstances, and the development of fresh lines of inquiry.
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Scientists can use chemicals to clean toxins from the soil. What does this
show about chemicals?
Any substance made of matter is by definition a chemical, which includes solids, liquids, and gases. Pure substances or mixtures of substances can both be found in chemicals. Water (H2O), for example, is a pure chemical because the same molecules and molecular combinations are present throughout its whole structure.
Explain about the chemicals ?Any material with a known composition is a chemical. Some chemicals, like water, are found in nature, meaning they always consist of the same "stuff." Other chemicals, including chlorine, are produced (used for bleaching fabrics or in swimming pools).
A chemical compound is a material that contains a specific combination of atoms or ions. Chemical compounds are made up of two or more elements coming together through a chemical process. While all substances are compounds, not all substances are compounds.
On its list of substances covered by the Toxic Substances Control Act, the EPA has more than 85,000 chemicals listed.
Not all chemicals are detrimental to the economy.
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A population is a group of plants or animals of the same ______ that live in an area.
Answer:
Species. A population is a group of plants or animals of the same species that live in an area.
What is the pH of a 0.83 M solution of sodium fluoride?
Report your answer to 2 decimal places.
The pH of a solution that is 0.67 M in sodium fluoride and 0.43 M in hydrofluoric acid is 8.53
What is the pH of a solution?The pH of a solution is the negative logarithm of the hydrogen ion concentration of the solution.
Mathematically:
pH = - log [H⁺]The pH of the given solution is calculated as follows:
Ka of HF = 7.2 * 10⁻⁴
Also, Kw = Ka * Kb
Kw = 1.0 * 10⁻¹⁴
Kb = 1.0 * 10⁻¹⁴ / 7.2 * 10⁻⁴
Kb = 1.39 x 10⁻¹¹
The [OH¯] is calculated using the Kb expression:
Kb = [OH⁻] * [H⁺] / [HA}
[OH⁻] = [H⁺] = x
Kb = x² / (0.83 - x)
Assuming x is negligible, the denominator = 0.83
x = √(1.39 x 10⁻¹¹ * 0.83)
x = 3.39 * 10⁻⁶
pOH = -log (3.39 * 10⁻⁶)
pOH = 5.47
pH = 14 - 5.47
pH = 8.53
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The atomic radius of a boron atom is 9 times 10-11m. Give its atomic radius in nanometres?
The atomic radius of boron atom is 0.09nm
What is an atomic radius?
Atomic radius, also known as atomic radii, is the total distance between an atom's nucleus and its electron's outermost orbital.
Atomic radius is thus defined as: The distance from the nucleus's center to the edge of its surrounding electron shells.
The radius of an atom is comparable to a circle's radius. The electron's most distant orbital is likened to the circle's outside edge, and the nucleus to the circle's center. The position of the outermost electron is unclear, making it challenging to calculate the atomic radii.
According to the question,
1m = 10-9nm
So, 9*10-11m = 0.09nm
The atomic radius of boron atom is 0.09nm
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When a bright light is shined on glow in the dark powder what is happening to the electrons.
a.The electrons are absorbing some of the light and are become excited.
b.The atoms become negatively charged ions.
c.Nothing, the electrons are not affected by light.
d.The electrons move to a lower energy state.
I cant figure this one out. How do I know ΔH∘ for the preceding reaction without knowing the standard enthalpie of F2?
The enthalpy of formation (ΔH°) of the given chemical reaction is equal to -905.3 KJ/mol.
What is the standard enthalpy of formation?The standard enthalpy of formation is defined as the change in enthalpy when one mole of a substance is formed from its pure elements under the standard state (1 atm of pressure and 298.15 K).
The standard enthalpy of formation is the energy released or absorbed when one mole of a substance is formed from its constituents under standard conditions. The symbol of the standard enthalpy of formation is represented by [tex]\triangle {H^o_f}[/tex].
The equation for the standard enthalpy change of formation for a balanced chemical reaction is shown below,
ΔH° (reaction) = ∑ [ΔH° of (products)− ∑ ΔH° of (Reactants)]
The standard enthalpy of the formation of fluorine gas = 0
The standard enthalpy of the formation of iodine gas = 62.23 KJ/mol
The standard enthalpy of the formation of IF₅ = -843 KJ/mol
ΔH° (reaction) = - 843 - 62.23 = - 905 .3 KJ/mol
Therefore, the enthalpy of formation (ΔH°) of the given chemical reaction is -905.3 KJ/mol.
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Can you please help me with 1-13
Answer:
E, C, A, 90, 5, D, B, D, D, D and B, A C and E, A, E
Explanation:
1. is correct, it is E
2. is C, not D. D is when the liquid is freezing/when the solid is melting.
3. the answer is A. B is when the gas is condensing or when the liquid is boiling.
4. 90 temperature units. This is the boiling point. Technically the substance can still condense below this point until 5 temperature units, or D, but ignore that.
5. 5 temperature units.
6. D, this is where the solid and liquids exchange states (ie melting/freezing)
7. B, this is where boiling and condensing occurs
8. Crystallisation is a fancy word for freezing. The melting and freezing points are the same, so D
9. D. Fusion means freezing.
10. D and B.
11. A, C, and E
12. A has the highest temperature and the highest kinetic and potential energy
13. E has the lowest kinetic and potential energy
The reaction of carbon with oxygen to produce carbon monoxide is an example of which type (or class) of reaction?2C(s) + O2(g) → 2CO(g)single replacementendothermicdouble replacementcatalyticcombination
Combination. Option E is correct.
Explanations:Given the chemical reaction between carbon and oxygen expressed as:
[tex]2C(s)+O_2(g)\rightarrow2CO(g)[/tex]From the equation, you can see that carbn combines with oxygen atom to produce carbonmonoxide. This type of reaction is known as the combination reaction since it involves the reaction of two elements to produce a compound (carbon monoxide)
Based on the explanations above, we can concude that the reaction of carbon with oxygen to produce carbon monoxide is an example of a combination reaction.
5. During factory inspection, Just Lemons, Inc. discovered that a water valve to the
lemonade mixing station was not functioning. Once they repair it, more water will
enter the mixing station. From what you know about the limiting and excess
ingredients for current lemonade production, what advice would you give engineers
about the upcoming increase in water?
The advise which would be given to the engineers is for them to determine the limiting reactant so water will not be in excess.
What is a Limiting reagent?This is referred to as the reactant which is completely used up in a chemical reaction and it helps to determine when the reaction stops. In this scenario, either water, lemon juice or sugar is a limiting reactant.
The best option in this scenario is to tell the engineers to determine the limiting reactant so as to ensure that the quality of lemonade made is maximized and is therefore the right choice.
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Question 1 (3 points)
Listed in the Item Bank are some important labels for sections of the image below.
Select the label for each corresponding area it identifies in
-noble gas
-alkaline earth metals
-transition metals
-alkali metals
-nonmetal
-metalloids
-halogens
The first column represent the alkali metal, the second column represent alkaline earth metals, the 3rd horizontal middle block is d block, the right 6 columns of the periodic table represent p block and the rightest column is noble gas.
What is noble gas, transition metals and it's places?See figuring out the right place of the elements mentioned in the periodic table is easy because its a predicted and factual thing.The first column we see in the periodic table is alkali metals.The second column we see in the periodic table is alkaline earth metals.The middle horizontal slit of elements called as d block elements starting from scandium.The right six columns belongs to p block elements and the rightest column represents noble gas elements.To know more about metals visit:
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The volume of a gas is 480 mL at 45.0 oC the temperature is increased to 60.0 oC at a constant pressure what is the new volume
Answer
The new volume = 0.503 L or 503 mL
Explanation
Given:
Initial volume, V₁ = 480 mL = (480/1000) = 0.480 L
Initial temperature, T₁ = 45.0°C = (45 + 273 K) = 318 K
Final temperature, T₂ = 60.0°C = (60 + 273 K) = 333 K
What to find:
The new volume, V₂ when the temperature increases to 60.0°C.
Step-by-step solution:
Since the pressure is constant, the new volume, V₂ can be calculated using Charle's law formula.
[tex]\begin{gathered} \frac{V_1}{T_1}=\frac{V_2}{T_2} \\ \\ \Rightarrow V_2=\frac{V_1T_2}{T_1} \end{gathered}[/tex]Plugging the values of the given parameters into the formula, we have
[tex]V_2=\frac{0.480L\times333K}{318K}=0.503\text{ }L[/tex]The new volume, V₂ when the temperature increased to 60.0°C = 0.503 L or (0.503 x 1000 mL) = 503 mL
What do you call a way of acquiring knowledge through experiment?
a.Academic method C.Scientific method
b.Experimental method d.Scientific notation
Answer:B
Explanation:
Predict the chemical formula for the ionic compound formed by V³⁺ and NO₂⁻
You can see that NO₂⁻ has an oxidation number of -1 and V³⁺ has an oxidation number of +3.
When we state the chemical formula of these compounds, we need to have that the algebraic sum of the oxidation numbers must be zero. In this case, we have that the sum is -1 + 3 = 2, it is incorrect because we need to have the result of zero.
For this problem, we can multiply three times NO₂⁻ obtaining that the oxidation number is -3, so the algebraic sum would be: (-1)(3) + 3 = -3 + 3 = 0. This means that the chemical formula will have three times NO₂⁻ bonded with V³⁺ and it would be:
[tex]V(NO_2)_3.[/tex]Provide the number of moles of Ca^ 2- ions contained in 0.125 L of 0.455 M solution of Ca 3 (PO 4 ) 2
Answer:
Moles of Ca3(PO4)2 = 0.455 M * 0.125 L = 0.0569 mol
1 Mole of Ca3(PO4)2 = 3 moles of Ca2+ ions
Thus, moles of Ca2+ ion = 3 * 0.0569 = 0.1707 ~ 0.171 moles
The number of moles of ions in a solution can be calculated using the molarity and volume of the solution. The number of moles of Ca ²⁺ ions contained in 0.125 L of 0.455 M solution of Ca₃ (PO₄) ₂ is 0.0170 moles.
What is molarity?Molarity is a term used to represent the concentration of the solution. Mathematically it is the ratio of number of moles of solute to the volume of solution in liters.
The molarity of the calcium phosphate solution is given 0.455 M and its volume is 0.125 L. Thus, the no.of moles of calcium phosphate in the solution is calculated as follows:
no.of moles of Ca₃ (PO₄) ₂ = molarity × volume
= 0.455 M × 0.125 L
= 0.0568 moles.
It is clear from the formula that one mole of calcium phosphate contains 3 moles of Ca ²⁺ ions. Therefore, the number of moles of calcium ions in 0.0568 moles of calcium phosphate is calculated as follows:
No. of moles of Ca ²⁺ ions = 0.0568 × 3
= 0.0170 moles.
Hence the number if moles of calcium ions in 0.125 L of 0.455 M calcium phosphate is 0.0170 moles.
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PLEASE HELP ASAP, I will mark the "brainiest"
In the generic reaction: 5A + 2B --> 6C + 3D The molar mass of A is 146.70g/mol while the molar mass of C is 21.31g/mol. If 4.253 g of A reacts with an excess of B, how many grams of C can form? Remember significant figures and units.
The amount, in grams, of C that can form from the reaction, is 0.7414 g.
Stoichiometric problemFrom the equation of the reaction, the mole ratio of A to that of C is 5:6.
In other words, for every 5 moles of A that reacts, 6 moles of C is produced.
Molar mass of A = 146.70 g/mol
Molar mass of C = 21.31 g/mol
Recall that: mole = mass/molar mass
Mole of 4.253 g of A = 4.253/146.70
= 0.029 mol
From the mole ratio, the equivalent mol of C that will be produced is:
0.029 x 6/5 = 0.03479 mol
mass = mole x molar mass
Mass of 0.03479 mol of C = 0.03479 x 21.31
= 0.7414 g (to the appropriate sig. fig.)
In other words, the amount of C that will be produced from 4.253 g of A will be 0.7414 g.
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How much work (in J ) is involved in a chemical reaction if the volume decreases from 4.25 to 1.97 L against a constant pressure of 0.838 atm ?
The amount of work (in J ) is involved in a chemical reaction if the volume decreases from 4.25 to 1.97 L against a constant pressure of 0.838 atm is: 8.78 Joules.
What is work done?The work done by an object can be calculated by multiplying the force acting on it by the perpendicular distance covered by the physical object. Also, the work done during a chemical reaction can be determined by multiplying the change in volume by the accompanying level of pressure.
Mathematically, the work done by a system is given by the formula:
Work done = PΔV = P(V₂ - V₁)
Where:
P represents the pressure.V represents the volume.Substituting the given parameters into the formula, we have;
Work done = 0.038(4.25 - 1.97)
Work done = 0.038(2.28)
Work done = 0.08664 L.atm
Next, we would convert L.atm to Joules:
Work done = 101.325 × 0.08664
Work done = 8.78 Joules.
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A student conducts an experiment to determine how the temperature of water affects the time for sugar to dissolve. In each trial, the student uses a different amount of sugar and a different temperature of water. What is wrong with this experimental design? Responses The student needs to perform more trials. The student needs to perform more trials. The student does not have a dependent variable. The student does not have a dependent variable. The student changed too many variables. The student changed too many variables. The student did not change enough variables.
Answer:
The student changed too many variables.
Can someone help me with this? I’m not understanding what it’s asking of me
Answer: You need to research what ever you are working on and find 2 examples.
Explanation:
How many moles of magnesium is 5.01 x 1022 atoms of magnesium?
Answer
Explanation
Note that a mole of any substance has 6.02 x 10²³ atoms of that substance.
Let x represent the mole of magnesium present in 5.01 x 10²² atoms of magnesium.
Therefore,
[tex]\begin{gathered} 1\text{ mole }=\text{6.02}\times10^{23}\text{ atoms} \\ x\text{ mole }=5.01\times10^{22}\text{ atoms} \\ \end{gathered}[/tex]Cross multiply, and divide both sides by 6.02 x 10²³ atoms to get x
[tex]undefined[/tex]
What is the expected product from the reaction of potassium with oxygen?K2O2K2OKO2KO
Potassium oxide is an ionic compound formed by combining potassium and oxygen. It carries the chemical formula K2O.
So, this is expected product from the reaction of potassium with oxygen because of the following:
To get the net charge of the compound equal to zero, we need to satisfy the equation K2O. So that's the answer.
A liquid in the lab has a density of 1.24 g/cm³ . What is the mass in grams of 254 mL of the liquid? I dont know where to start when to convert because of the Activ app. I need help on how to answer this.
The mass in grams of the 254 mL of the liquid, given that it has a density of 1.24 g/cm³ is 314.96 grams
How to determine the mass of the liquidWe'll begin by listing the out the parameters obtained from the question. This is given below:
Density of liquid = 1.24 g/cm³Volume of liquid = 254 mL = 254 cm³Mass of liquid =?The mass of the liquid can be obtained as follow:
Density = mass / volume
Cross multiply
Mass = Density × Volume
Mass of liquid = 1.24 × 254
Mass of liquid = 314.96 grams
Thus, the mass of the liquid is 314.96 grams
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Consider the following processes: 1. A ─→ B delta H = ─100 kJ 2. B ─→ C + D delta H = ─50 kJ 3. E ─→ D delta H = ─25 kJ What is the delta H for the process: A ─→ C + E?
The enthalpy change, ΔH of the process: A → C + E is -125 kJ.
What is the enthalpy change of a reaction?The enthalpy change of a reaction is the sum of the heat changes that occur as reactants combine to form products.
The enthalpy change of the reaction is given by the following formula:
Enthalpy change = sum of energy of bonds broken - sum of energy of the bonds formedΔH = ∑H(bonds broken) - ∑H(bonds formed)The delta H for the process A → C + E is given as follows;
1. A ─→ B ΔH = ─100 kJ
2. B ─→ C + D ΔH = ─50 kJ
3. E ─→ D delta H = ─25 kJ
-3. D → E = +25 kJ
A → C + D = 1 + 2 + (- 3)
A → C + E = (- 100 - 50 + 25) kJ
A → C + E = -125 kJ
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This alkyl halide can be prepared by electrophilic addition of HBr to 2 different alkenes. Draw them
This alkyl halide can be prepared by electrophilic addition of HBr to 2 different alkenes because of alkenes undergo hydrogenation in presence of acid and base when HBr can added to the different alkyl 3-methyl-hex-2-ene, 3-methyl-hex-3-ene and 3-methylene hexane
Hydrogenation is the chemical reaction in which molecular hydrogen and another compound and element usually in presence of catalyst such as nickel, palladium or platinum and this process is commonly employed to reduce or saturated organic compound
Addition of hydrogen and halogen to the double bond or triple bond based on markovnikov rule of addition and when HBr is added to CH3- CH=CH2 then Br is added to CH group and H is added to the CH₂ group of the alkene and if the reaction is carried in the presence of any peroxide then reverse addition is taking place
Then different alkyl structure such as 3-methyl-hex-2-ene, 3-methyl-hex-3-ene and 3-methylene hexane and image is given below
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