Answer:
A vacuum flask (also known as a Dewar flask, Dewar bottle or thermos) is an insulating storage vessel that greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck. The gap between the two flasks is partially evacuated of air, creating a near-vacuum which significantly reduces heat transfer by conduction or convection.

The typical design of a Thermos brand vacuum flask, used for maintaining the temperature of fluids such as coffee.

Laboratory Dewar flask, Deutsches Museum, Munich

Diagram of a vacuum flask

A cryogenic storage dewar of liquid nitrogen, used to supply a cryogenic freezer
Vacuum flasks are used domestically, to keep beverages hot or cold for extended periods of time, and for many purposes in industry.
pls make me as brainliest
5) answer is A
2NaHCO3(s) + 129k) - Na2CO3(s) + H2(g) + CO2(g)
This equation indicates that AH is
and energy must be
to complete the reaction.
A)
positive; added
B)
negative; added
C)
positive; released
D)
negative; released
Answer:
A) positive; added
Explanation:
Based on the reaction:
2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)
2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.
That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.
Thus, right answer is:
A) positive; added
Who goes to K12 and if so what grade
Answer:
I do. I am in tenth. What area are you in?
Explanation:
Answer:
8th finna be in 9th wbu
Explanation:
Choose ALL
BIOTIC factors
Lesson 5.01
Question 1 options:
protists
animals
fungi
plants
salinity
Answer:
protists
animals
fungi
plants
Explanation:
i took the test let me know if im wrong tho
The biotic factors from the following options are protist, animals, fungi, and plants. Options A, B, c, and D are correct.
What are biotic factors?Biotic factors are those factors which can grow, and reproduce themselves.
Plants, animals, protists, and fungi are biotic factors that live, eat ad reproduce.
Salinity is the quality of any solution. It is not a biotic factor.
Thus, the correct options are A, B, c, and D.
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Base A dissociates 25% in water. Base B dissociates 50%. Base C dissociates
75%. Which base is the WEAKEST conductor of electricity?
Answer:Base A is the weakest conductor electricity
Explanation:
Dissociation is a factor that affects electrical conductivity. The greater the percentage of dissociation for bases the stronger the conductivity of electricity.
Given that
Base A dissociates 25% in water
Base B dissociates 50%.
Base C dissociates 75%
We can conclude that Base A is the weakest conductor oelectricity since it has the lowest percentage of dissociation.
Which pH is the most acidic
Answers choices below
A. 7
B. 14
C. 0.5
D . 1
C. 0.5
This is the answer.
(assuming that the D option is 1, if it is 0.1 then the answer is 0.1)
[tex]0.5[/tex]
Explanation:
As you know that decreasing in the concentration of OH- (i.e., 14, 13, 12, 11,..) makes to increase in the concentration of H+ ions (5,4,3,2,1).
You will be marked as brainlest if you are able to solve this question
Answer:
See Explanation
Explanation:
1) According to the question, the reactivity of a metal is measured by the temperature of the solution after reaction. The higher the temperature of the solution, the greater the reactivity of the metal. Based on this criterion, the metals can be arranged in an order of reactivity as follows;
Mg> Zn > Fe.
2) The equation of the reaction is;
Mg(s) + 2H^+(aq) ------>Mg^2+(aq) + H2(g)
If we consider the changes in oxidation number from left to right;
The oxidation number of Mg changed from zero to +2
The oxidation number of H changed from +1 to zero
Recall that a redox reaction is a reaction in which the oxidation number of species changes from left to right in the reaction. Hence this reaction is a redox reaction.
The reducing agent experiences an increase in oxidation number. In this case, Mg is the reducing agent.
The oxidation half equation is;
Mg(s) ------> Mg^2+(aq) + 2e
The reduction half equation is;
2H^+(aq) + 2e ------> H2(g)
A student finds that the water's temperature went from 18oC to 38oC. Calculate how many calories are in the peanut.
Answer:
567 calories.
Explanation:
There 567 calories in 100 grams of peanut. In 100 grams of peanut, 49 gram is the fat, 26 grams of protein, 16 grams of carbohydrates, Sodium is 18 mg, Potassium is 705 mg. Calcium is present in peanut about 9%, Iron is 25% , Vitamin B-6 is 15% and Magnesium is 42% of their total weight. Oil content is high in the Peanut so this is the reason for high calories in peanut. It is a good source of proteins and potassium.
What are the two groups the animal kingdom is divided into?
Answer:
Taking the animal kingdom as an example, we can see that it is split into two clear groups: Invertebrates - animals without a backbone. Vertebrates - animals with a backbone.
Explanation:
Which of the following best explains the relationship between peak to peak amplitude and semi amplitude
Answer:
Which of the following best explains the relationship between peak-to-peak amplitude and semi-amplitude? Semi-amplitude is half the distance of the peak-to-peak amplitude. Semi-amplitude is the same distance as the peak-to-peak amplitude.
What is the role of a consumer in the flow of energy through a food chain?
Answer:
The role of consumers in an ecosystem is to obtain energy by feeding on other organisms and sometimes transfer energy to other consumers. Changes that affect consumers can impact other organisms within the ecosystem.
Explanation:
Hope this helped Mark BRAINLIEST!!!!
Consumers are organisms that obtain energy by eating other organisms. Consumers may consume either producers or other consumers. Consumers include animals.
What is food chain ?A food chain is a network of links in a food web that begins with producer organisms and ends with an apex predator, detritivore, or decomposer species.
A food chain also demonstrates how organisms are related to one another through the food they consume. Each trophic level is represented by a different level of a food chain.
Producers can produce their own food and energy, but consumers are not the same. Consumers are living things that must hunt, gather, and eat their food.
Thus, Consumers must eat in order to gain energy, or they will perish. Omnivores, carnivores, herbivores, and decomposers are the four types of consumers.
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what is the k expression for this reaction? plz help !
Answer:
K = [HI]² / [H₂] [I₂]
Explanation:
To write the expression of equilibrium constant, K, it is important that we know how to obtain the equilibrium constant.
The equilibrium constant, K for a given reaction is simply defined as the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient. Thus, the equilibrium constant is written as follow:
K = [Product] / [Reactant]
Now, we shall determine the equilibrium constant for the reaction given in the question above. This can be obtained as illustrated below:
H₂(g) + I₂(g) —> 2HI (g)
K = [HI]² / [H₂] [I₂]
Balancing Equations help (please explain)
Answer:
A balanced equation is an equation for a chemical reaction in which the number of atoms for each element in the reaction and the total charge is the same for both the reactants and the products. In other words, the mass and the charge are balanced on both sides of the reaction.
Explanation:
correct name for Ti(SO4)2?
Answer:
Titanium(IV) Sulfide
Explanation:
Definition: This is the energy that comes to Earth from the Sun.
Example: using the sun to dry your laundry hanging on the clothesline
Answer:
well to me it is called natural energy
PLEASE HELP ASAP!!
WHAT IS THE CYCLE OF OZONE IN THE STRATOSPHERE?
A. UV splits an oxygen molecule into two oxygen atoms, which combine with a oxygen molecule to create ozone.
B. An ozone molecule splits into an oxygen molecule and an oxygen atom.
C. An ozone molecule forms from and then splits into two oxygen molecules and two oxygen atoms.
D. A & B
Which of the following is not a renewable source of energy?
1.) geothermal
2.) coal
3.) solar
4.) wind
2. Coal
It is non renewable energy source.
Answer: the answer would be coal
Explanation: hoped this helped!
Question is in picture! Due in 30 minutes!
Answer:
wheresthepicture.-
Explanation:
Answer:
don't see a picture
Explanation:
During a reaction, H for reactants is -750 kJ/mol and H for products is 920 kJ/mol. Which statement is correct about the reaction and correctly compares the energy in bonds?
Answer:
a
Explanation:
the ones are stronger and herder to break so it will take more energy to break them then when they are made
The statement, that describes the reaction and correctly compares the energy in bonds from the given ΔH values is "It's endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed."
What is ΔH?The quantity of energy evolved during a chemical reaction is represented by ΔH, also known as enthalpy change.
An exothermic reaction is a chemical reaction in which heat energy is emitted. The value of ΔH is always negative in exothermic processes. An endothermic reaction is a chemical reaction that absorbs heat energy. The value ΔH of is always positive for endothermic reactions.
When the bonds in the reactants are broken, more energy is absorbed than is released when new bonds are created in the products, therefore the value of ΔH is always positive in endothermic reactions.
Hence the correct option is endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed.
Learn more about ΔH here
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A gas has a volume of 300 mL in a rigid container at 50oC and 1.75 atm. What will be its pressure at 100K?
Answer:
Its pressure will be 0.54 atm at 100 K.
Explanation:
Gay-Lussac's law indicates that, as long as the volume of the container containing the gas is constant, as the temperature increases, the gas molecules move faster. Then the number of collisions with the walls increases, that is, the pressure increases. That is, the pressure of the gas is directly proportional to its temperature.
Gay-Lussac's law can be expressed mathematically as the quotient between pressure and temperature equal to a constant:
[tex]\frac{P}{T} =k[/tex]
Studying two different states, an initial state 1 and a final state 2, it is satisfied:
[tex]\frac{P1}{T1} =\frac{P2}{T2}[/tex]
In this case:
P1= 1.75 atmT1= 50 °C= 323 K (being 0 C=273 K)P2= ?T2= 100 KReplacing:
[tex]\frac{1.75 atm}{323 K} =\frac{P2}{100 K}[/tex]
Solving:
[tex]P2= 100 k*\frac{1.75 atm}{323 K}[/tex]
P2= 0.54 atm
Its pressure will be 0.54 atm at 100 K.
Please help me ASAP!!!!
Answer:
Explanation:
Determine the balanced chemical equation for the chemical reaction.
Convert all given information into moles (most likely, through the use of molar mass as a conversion factor).
Calculate the mole ratio from the given information.
Balance the chemical equation using the drop-down options.
CaC2 +
A H20 --->
Ca(OH)2
A C2H2 +
Answer:
CaC2 + 2H20 ⇋Ca(OH)2 + C2H2
Explanation:
CaC2 + A H20 ---> Ca(OH)2 + A C2H2
This is calcium carbide reacting with water to produce calcium hydroxide and ethyne commonly called acetylene.
Let's now balance the equation.
CaC2 + 2H20 ⇋Ca(OH)2 + C2H2
Your simulation involved 100 atoms and eight half-life cycles. For half-life cycles 9 and later, how many radioactive nuclei would you expect to be present?
Answer:
you would expect 0 radioactive nuclei to be present
Explanation:
got it right on the assignment
The student then takes a 1.00M stock solution of table sugar (sucrose C12H22O11) and mixes 0.305L of stock solution with additional distilled water to create a dilute solution with a total volume of 1.25L.
Explain how the student can determine the molarity of the resulting solution. Show a valid calculation for the final molarity. PLS HELP
Answer: The molarity of final solution is 0.244 M.
Explanation:
Given: [tex]M_{1}[/tex] = 1.00 M, [tex]V_{1}[/tex] = 0.305 L
[tex]M_{2}[/tex] = ?, [tex]V_{2}[/tex] = 1.25 L
Formula used to calculate the molarity f resulting solution is as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]
Substitute the values into above formula as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}\\1.00 M \times 0.305 L = M_{2} \times 1.25 L\\M_{2} = \frac{1.00 M \times 0.305 L}{1.25 L}\\= 0.244 M[/tex]
Thus, we can conclude that the molarity of final solution is 0.244 M.
Anyone know this question
which of the following examples where molecules are slightly far apart
A.rock
B.water
C.smoke
D.plasma ball
Answer:
in my opinion I think is D you don't have to choose it
24.
What is the molar mass of CO2?
Answer:
The molecular mass of carbon dioxide is 44.01amu
URGENT: Identify the subatomic particles that determine the atomic number of an element.
Answer:
the number of protons determines the atomic number
Explanation:
Ex. Aluminum has 13 protons, so it's atomic number is 13
hope this helps :)
Given the following electronic configurations, identify how many valence electrons each atom has.
A=
Element
Electron Configuration
Number
of
Valence
Electrons
B =
C=
Sodium
(Na)
152 2s 2p 3s
А
DONE
Oxygen (0)
1s 2s 2p
B
Iron (Fe)
1s 2s 2p 3s 3p 452
306
С
Answer:
sodium=atomic number 11 it electronic configuration is ,K=2, L=8,M=1 Valence is 1
oxygen= atomic number 8 it electronic configuration is K=2, L=6 Valence is 2
iron= atomic number 26 it electronic configuration is K= 2 L= 8,M=8 N=6 Valence 2
Answer: A=1
B=6
C=8
Explanation:
A Chemist reacted magnesium and aluminum oxide. A reaction takes place. Explain why
Explanation:
when Magnesium is reacted with Aluminum oxide, Aluminum being a less reactive metal than magnesium, is replaced by magnesium
Al2O3 + 3Mg - 3MgO + 2Al
hence reaction takes place
Consider the following reaction: 2 SO2(g) + O2(g) → 2SO3(g)
If the initial rate of change for sulfur dioxide is -2.00 M/min, what is the initial rate of change of oxygen?
A) -4.00 M/min
B) -1.00 M/min
C) 4.00 M/min
D) 1.00 M/min
Answer:
B) -1.00 M/min
Explanation:
Based on the reaction:
2 SO2(g) + O2(g) → 2SO3(g)
2 moles of SO2 are consumed per mole of O2 producing 2 moles SO3
In the problem, the sulfur dioxide has a rate of change of -2.00M/min. As the moles of oxygen that reacted are half the moles of SO2, its rate of change is halved, that is:
B) -1.00 M/min