Answer:
Minimizes heat transfer
Explanation:
To keep my lunch from getting cold at the beach, a material the minimizes heat transfer will be the most desirable.
Such material should be modified to prevent had transfer by convection, conduction and radiation. This kind of material is desirable because heat generally flows from a place of high amount to that of low amount. Since the food will mostly have a temperature higher than the ambient one, it is expected that heat will flow away from the food to the environment. This will make the food cold. If such heat transfer is prevented, then, the food will remain hot.Cells pump definition
Answer:
Pumps also called transporters, are transmembrane proteins that actively move ions and/or solutes against a concentration or electrochemical gradient across biological membranes.
is metal and plastic beads magnetism, state of matter, or solubility?
please help!!!!
How to make the solar oven using the following materials
-pizza box
-aluminium foil
-mirror
-hot glue
-chopstick
Answer:
hot glue
Explanation:
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What element produced the unknown emission spectrum?
Answer:
The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state.
The pressure of a 5.0 L sample of gas changes from 3.0 atm to 10.0 atm while the temperature remains constant. What is the gas’s new volume?
Answer:
The answer is 1.5 LExplanation:
The new volume can be found by using the formula for Boyle's law which is
[tex]P_1V_1 = P_2V_2[/tex]
Since we are finding the new volume
[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]
From the question we have
[tex]V_2 = \frac{5 \times 3}{10} = \frac{15}{10} = \frac{3}{5} \\ [/tex]
We have the final answer as
1.5 LHope this helps you
Add oxidation numbers to the following reaction: 2 H3PO4 (aq) + 2 Cr(s) → 2 CrPO4 (aq) + 3 H2(g). Identify the atom that is oxidized and identify the oxidizing agent.
The atom that is oxidized : Cr
The oxidizing agent : H₃PO₄
Further explanationReaction
2 H₃PO₄ (aq) + 2Cr(s) → 2 CrPO₄ (aq) + 3H₂(g)
Atoms undergoing a reduction reaction (decrease in oxidation number) and an oxidation reaction (increase in oxidation number)
Reduction (+1 to 0)H⁺(in H₃PO₄) =+1
H₂=0
Oxidation (0 to +3)Cr = 0
Cr³⁺(in CrPO₄ )
the oxidizing agent.⇒which undergoes a reduction reaction and oxidizes another compound/element : H₃PO₄
Calculate the mass percent composition of iron for the third one of these iron ores.
Iron is mined from the earth as iron ore. Common ores include Fe2O3 (hematite), Fe3O4 (magnetite), and FeCO3 (siderite).
Answer:
[tex]\% Fe=48.2\%[/tex]
Explanation:
Hello!
In this case, since the percent composition of an element in a compound is given by:
[tex]\% i =\frac{z_i*m_i}{MM}*100\%[/tex]
Whereas i represent the element in the compound for which we want compute the mass percent. As required for siderite, FeCO3 whose molar mass is 115.854 g/mol, and knowing there is one iron atom there with an atomic mass od 55.85 g/mol, the mass percent of iron there is:
[tex]\% Fe=\frac{1*55.85}{115.854}*100\%\\\\\% Fe=48.2\%[/tex]
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Why are the sublevels within a principal level split into different energies for multi-electron atoms but not for hydrogen atom?
Answer:
Kindly check the explanation section.
Explanation:
Hydrogen in the periodic chart/table is the first element on the periodic table with binding energy of 0.000± 0.0000 keV, Isotopic mass of 1.007825 u, one or single proton and a spin value of half(1/2).
The first thing to note for the fact that hydrogen's sublevels within a principal level does not split into seperate or different energies is that THERE IS A VACANT GROUND STATE IN HYDROGEN ATOM. With this, it makes it impossible for the electrons that are inside to get infiltrated which is the case with the atoms with multielectron.
NB: Penetration is done by electrons outside.
A student needs to use the metric system while measuring the length of a box. Which units should he use?
AWNSER FAST PLEASEEE
Answer:
Centimeters or milimeters.
Explanation:
The answer depends on the size of the box.
The metric system base unit for length is the meter. Centimeters and milimeters are thus also part of the metric system.
If the box is a "regular-sized" box that we use to put stuff in (books, presents, etc), then centimeters would be the most appropiate.
If we're talking about those tiny boxes that are printed on paper (for example in some notebooks) then milimeters would be the most appropiate.
Answer:
Centimeters
Explanation:
The barometric pressure measured outside an airplane at 3 km ( ft) was 524 mmHg. Calculate the pressure in kPa.
Answer:
69.8609 KPa.
Explanation:
The following data were obtained from the question:
Pressure (in mmHg) = 524 mmHg.
Pressure (in KPa) =?
Thus we can obtain the pressure in KPa as follow:
760 mmHg = 101.325 Kpa
Therefore,
524 mmHg = 524 mmHg × 101.325 KPa / 760 mmHg
524 mmHg = 69.8609 KPa
Thus, 524 mmHg is equivalent to 69.8609 KPa.
Write a balanced half-reaction describing the oxidation of aqueous iodide anions to gaseous diiodine.
Answer:
I might be a little late but in case anyone in the future needs it the answer is 2I^-(aq) ---> I_2(g)+2e^-
The balanced half reaction describing the oxidation of aqueous iodide anions to gaseous diiodine is;
2I-(aq). ==>. I2(g) + 2e-Definition:
Oxidation as determined by oxidation Numbers simply refers to an increase in oxidation number.
In essence, the chemical reaction above involves the increase in oxidation number of Iodine, I from -1 to 0.
The half reaction is thus so, because gaseous diiodide is a diatomic element.
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List any three quantum numbers that describe an electron in an atom and state the relationship between any of the two
Explanation:
To completely describe an electron in an atom, four quantum numbers are needed: energy (n), angular momentum (ℓ), magnetic moment (mℓ), and spin (ms).
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How much water must be added to 424 mL of 0.189 M HCl to produce a 0.140 M solution?
Answer:
Volume of water added = 148.4 mL
Explanation:
Given data:
Initial volume = 424 mL
Initial molarity = 0.189 M
Final molarity = 0.140 M
Volume of water added = ?
Solution:
Formula:
M₁V₁ = M₂V₂
0.189 M×424 mL = 0.140 M×V₂
V₂ = 0.189 M×424 mL /0.140 M
V₂ = 80.136 M.mL / 0.140 M
V₂ = 572.4 mL
Final volume of solution is 572.4 mL.
Volume of water added = Final volume - initial volume
Volume of water added = 572.4 mL - 424 mL
Volume of water added = 148.4 mL
how many sodium ions are in 1.4 kg of sodium chloride, NaCl?
Answer:
1.44 x 10²⁵ ions of Na⁺
Explanation:
Given parameters:
Mass of NaCl = 1.4kg = 1400g
Unknown:
Number of ions of sodium = ?
Solution:
The compound NaCl in ionic form can be written as;
NaCl → Na⁺ + Cl⁻
In 1 mole of NaCl we have 1 mole of sodium ions
Now, let us find the number of moles in NaCl;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Number of moles = [tex]\frac{1400}{58.5}[/tex] = 23.93mol
So;
Since 1 mole of NaCl gives 1 mole of Na⁺
In 23.93 mole of NaCl will give 23.93 mole of Na⁺
1 mole of a substance = 6.02 x 10²³ ions of a substance
23.93 mole of a substance = 6.02 x 10²³ x 23.93
= 1.44 x 10²⁵ ions of Na⁺
Luca made the following chart for Earth’s four basic movements. What needs to be correct on his chart
Answer:
The solar system speed and Milky Way speed should be switched
Explanation:
Answer:
Explanation:
The solar system speed and Milky Way speed should be switched
Consider the following reaction:2 HgCl2(aq) + C2O42-(aq) 2 Cl-(aq) + 2 CO2(g) + Hg2Cl2(s)(a) The rate law for this reaction is first order in HgCl2(aq) and second order in C2O42-(aq). What is the rate law for this reaction?Rate = k [HgCl2(aq)] [C2O42-(aq)]Rate = k [HgCl2(aq)]2 [C2O42-(aq)]Rate = k [HgCl2(aq)] [C2O42-(aq)]2Rate = k [HgCl2(aq)]2 [C2O42-(aq)]2Rate = k [HgCl2(aq)] [C2O42-(aq)]3Rate = k [HgCl2(aq)]4 [C2O42-(aq)](b) If the rate constant for this reaction at a certain temperature is 0.0169, what is the reaction rate when [HgCl2(aq)] = 0.158 M and [C2O42-(aq)] = 0.202 M?Rate = M/s.(c) What is the reaction rate when the concentration of HgCl2(aq) is doubled, to 0.316 M while the concentration of C2O42-(aq) is 0.202 M?Rate = M/s
Answer:
b
Explanation:
Calcium sulfide has a face-centered cubic unit cell with calcium ions in octahedral holes and sulfide ions at the lattice points. How many ions of each element are contained in each unit cell
Answer:
4 calcium ions and 4 sulfide ions.
Explanation:
In a face centered unit cell, 8 corners of the unit cell are occupied by 8 atoms. Each corner is 1/8 of a cell. In addition it has 6 atoms in the face of the lattice, which is 1/2 of a cell. (1/8 * 8) + (1/2 * 6) = 4. CaS has a 1:1 ratio. Therefore, they each have 4 ions.
Each cubic unit cell contains FOUR (4) calcium ions in octahedral holes and FOUR (4) sulfide ions at the lattice points.
Calcium sulfide is a solid inorganic compound (chemical formula: CaS) that shows a white appearance and crystallizes in cubes like rock salts. This molecule (calcium sulfide) is widely used to produce certain classes of paints, ceramics, paper, etc.Calcium has a valence of 2 electrons, while sulfur has '6' valence electrons, thereby the number of valence electrons in CaS is equal to 2 + 6 = 8.Calcium sulfide (CaS) adopts a sodium chloride crystal structure where each CaS unit cell contains four sulfide (S²⁻) ions and four calcium (Ca²⁻) ions.In conclusion, each cubic unit cell contains FOUR (4) calcium ions in octahedral holes and FOUR (4) sulfide ions at the lattice points.
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Why do scientists' study and synthesize new transuranium elements in the laboratory?
Explanation:
Nuclear structure and stability
Although the decay properties of the transuranium elements are important with regard to the potential application of the elements, these elements have been studied largely to develop a fundamental understanding of nuclear reactions and nuclear and atomic structure.
If the concentration of a reactant is tripled (all other things remain constant), and the reaction rate increases nine times, what is the reaction order with respect to the tripled reactant? Enter your answer as a number.If the concentration of a reactant is increased 1.5 times (all other things remain constant), and the reaction rate increases 2.25 times, what is the reaction order with respect to the reactant? Enter your answer as a number.If the concentration of a reactant is tripled (all other things remain constant), and the reaction rate remains constant, what is the reaction order with respect to the tripled reactant? Enter your answer as a number.When 29.0 mL of 0.220 M KIO3 is combined with 38.0 mL of H2SO3 and 50.0 mL of water, what is the resulting concentration of KIO3?
The reaction order for the following conditions are:
a. two
b. two
What do you mean by reaction order?Reaction order is the number of reactants, whose concentration affects the reaction rate.
The reaction order can be determined by adding the exponents of each reactant.
The rate equation is [tex]v^0 = k[A]^x + k[B]^y[/tex]
The first-order reaction is in which the reaction is dependent on one variable concentration.
The second-order reaction is that in which the reaction is dependent upon the concentration of two variables.
Thus, the correct options are a. two, b.two.
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Heavier compounds tend to have higher boiling points. However, sulphur dichloride (Mr= 103.1 gmol-1) and sulphur hexafluoride (Mr = 146.1 g mol-1) have the boiling point of 59 °C and -50.8 °C respectively. Explain this phenomenon.
write the formular of the compound formed when element D and oxygen react together
Answer:
D oxide
Explanation:
Hope this helped!
Calculate ΔHrxn for the following reaction:CH4(g)+4Cl2(g)→CCl4(g)+4HCl(g)Use the following reactions and given ΔH′s.C(s)+2H2(g)→CH4(g)ΔH=−74.6kJC(s)+2Cl2(g)→CCl4(g)ΔH=−95.7kJH2(g)+Cl2(g)→2HCl(g)ΔH=−184.6kJ
Answer:
ΔH= -390.3kJ
Explanation:
Using Hess's law, we can obtain ΔHrxn from the sum of related reactions.
Using:
(1) C(s) + 2H2(g) → CH4(g) ΔH=−74.6kJ
(2) C(s) + 2Cl2(g) → CCl4(g) ΔH=−95.7kJ
(3) H2(g) + Cl2(g) → 2HCl(g) ΔH=−184.6kJ
(2) - (1):
CH4(g) + C(s) + 2Cl2(g) → CCl4(g) + C(s) + 2H2(g)
CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g)
ΔH= -95.7kJ - (-74.6kJ) = -21.1kJ
This reaction + 2*(3):
2H2(g) + 2Cl2(g) + CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g) +4HCl(g)
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
ΔH= -21.1kJ + 2*-184.6kJ
ΔH= -390.3kJHow many atoms of phosphorus are in 5.70 mol of copper(II) phosphate?
Answer:
Cu3 (PO4)2 contains a total of 2 atoms of phosphorus in just one molecule. (2.10 mol)(6.02214 x 10^23 atoms / mol)(2 phosphorous) = 2.53 x 10^24 atoms of phosphorous per molecule of copper i
Explanation:
Determine the molarity of a solution prepared by dissolving 0.198 g of "KHP" (C8H5O4K) in enough water to make 125 mL of solution.
When the solution is found and titrated with aqueous sodium hydroxide, the endpoint is reached after the addition of 27.80 mL of base solution. How many moles of NaOH reacted? What is the concentration of the NaOH?
Answer:
0.007756M KHP; 0.0009695 moles NaOH reacts; 0.03488M NaOH.
Explanation:
Potassium hydrogen phthalate, KHP, is a salt used as standard to determine concentration of basic solutions as NaOH solutions.
To find molarity of the KHP solution we need to convert mass of KHP to moles and divide this in 125mL = 0.125L:
Moles KHP -Molar mass: 204.22g/mol-:
0.198g * (1mol / 204.22g) = 0.0009695 moles KHP
Molarity:
0.0009695 moles KHP / 0.125L = 0.007756M KHP
NaOH reacts with KHP as follows:
NaOH + KHP → Na⁺ + KP⁻ + H₂O
That means 1 mole of NaOH reacts per mole of KHP, that means moles of NaOH that reacts are = Moles of KHP added:
0.0009695 moles NaOH reacts
In 27.80mL = 0.02780L the NaOH was contained. Molarity is:
0.0009695 moles NaOH / 0.02780L =
0.03488M NaOH
Moles of NaOH added will be "0.034".
According to the question,
→ [tex]Molarity = \frac{Number \ of \ moles}{Volume}[/tex]
By substituting the values, we get
[tex]= \frac{0.198}{204}\times \frac{1000}{125}[/tex]
[tex]= 0.0077 \ M[/tex]
Let,
The number of moles added be "[tex]M_2[/tex]".Now,
→ [tex]M_1 V_1 = M_2 V_2[/tex]
→ [tex]0.0077\times 125=M_2\times 27.8[/tex]
→ [tex]M_2 = 0.034 \ moles[/tex]
Thus the above answer is appropriate.
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A crow flies 100 meters east in 5 minutes. What is the crow’s velocity?
Answer: 20 m/min east
Explanation: The speed is distance divided by time
distance between start-point and end-point = 100 meters
time to cover the distance = 5 minutes
100 m ÷ 5 min = 20 m/min east
you have to add east since velocity is the measure of speed and direction and your answer needs to include the direction
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5. Which two body systems work together to bring oxygen into the body's cells
and take carbon dioxide away?
A. Nervous and endocrine
B. Respiratory and digestive
C. Respiratory and circulatory
D. Muscular and skeletal
Answer:
C
Explanation:
the respiratory system and the circulatory system work closely together to deliver oxygen to cells and to get rid of the carbon dioxide the cells produce. The circulatory system picks up oxygen in the lungs and drops it off in the tissues, then performs the reverse service for carbon dioxide.
The two-body systems that work together to bring oxygen to the body's cells and remove carbon dioxide are the RESPIRATORY system and CIRCULATORY system (Option C).
The red blood cells of the circulatory system transport oxygen from the lungs and other nutrients to all the cells of the body, which are required to carry out a process called cellular respiration.
Moreover, carbon dioxide is also transported in the red blood cells to the lungs in the opposite direction.
The alveoli in the lungs of the respiratory system function to absorb oxygen from the air through the process of inhalation and subsequently eliminate carbon dioxide through exhalation.
In conclusion, the two-body systems that work together to bring oxygen to the body's cells and remove carbon dioxide are the RESPIRATORY system and CIRCULATORY system (Option C).
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Which of the following examples of erosion would occur most quickly?
OA. A river erodes sediment to form a canyon.
ОВ.
A glacier carves out a path as it moves.
OC. A wind storm moves sand from one area to another
OD
Ocean waves erode a large rocky cliff.
Answer: OC
Explanation:
The Others Could Take Many Millions Of Years
The diagram shows water in a graduated cylinders. Graduated cylinder B has 30 mL of water.
What is this statement and example of?
(4 Points)
Prediction
A theory
An observation
A hypothesis
Which of the following indicates that an endothermic reaction has occurred?
Heat is released
Water is formed
Salt is produced
Temperature decreases
ive seen people say that its A but I don't think so because heat is released when its an exothermic reaction not an endothermic.
will mark brainiest if you get it right
Answer:
Temperature decreases
Explanation:
The correct answer that indicates that an endothermic reaction has occurred would be a reaction in which the temperature decreases.
An endothermic reaction is a reaction in which energy in the form of heat is absorbed from the surrounding. Hence, the final temperature of an endothermic reaction is usually lower than the initial temperature.
Endothermic reactions are the complete opposite of exothermic reactions in which heat is given off in the course of the reactions. Hence, the temperature of the reaction in exothermic reactions increases instead of decreasing.
In summary, a decrease in temperature of a reaction is an indication that heat has been absorbed during the course of the reaction and such a reaction is said to be endothermic.
Answer: Temperature Decreases
Explanation: Endothermic reaction is when heat is released meaning the temperature will decrease.
Draw the structures of the starting materials needed to make 2‑methylhept‑3‑yne or 2‑methyl‑3‑heptyne. The starting materials may be any bromoalkane having five carbons or fewer.
Answer:
Explanation:
The structures of the starting materials 2‑methylhept‑3‑yne can be seen in the diagram attached below. We will also notice the role of NaNH₂ which acts as a strong base and whose function is to extract acidic proton and form an alkyne as a product.
The reaction with NaNH₂ yields acetylide ion which is then reacted with a straight-chain alkyl halide to form an extended carbon chain.
CHECK THE DIAGRAM BELOW.