Answer: hope this helps mark me BRAINLEST plz ;)
Explanation:42. Practice Problem How many joules of energy are required to vaporize 423g of water at 100oC and 1atmosphere of pressure. q = mHv m = 423 g Hv = 2260 J/gq = (423g) (2260J/g) = 955,980 J = 956 43. Table T – Heat Formulas
The amount of heat needed to melt 423 g of water at 0°C is 141282 J
The heat required to melt water can be obtained by using the following formula:
Q = mLQ is the heat required.
L is the latent heat of fusion (334 J/g)
m is the mass.
With the above formula, we can obtain the heat required to melt the water as illustrated below:
Mass of water (m) = 423 g
Latent heat of fusion (L) = 334 J/g
Heat (Q) required =?Q = mL
Q = 423 × 334
Q = 141282 JTherefore, the amount of heat needed to melt 423 g of water at 0°C is 141282 J
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What is empirical evidence
A retest of experimental results to make them reliable
Knowledge gained by observation or measurement
A prediction of test results before an experiment
A conclusion derived from evidence and logical reasoning
Please help me..
Will give the brainliest
Urgent
Please answer correctly
Explanation:
a) blue litmus paper turns red when u add acid in it .
b) red litmus paper , when an alkali dissolves in water it produce hydroxide ions
which cause it to become a alkaline
why do we need to calibrate equipment
Answer:
to be precise in the calculations
Explanation: for example your cell phone has a gps inside it, the gps is responsible for providing direction data like a compass, if the equipment is not calibrated, the gps will not find the correct direction.
How many significant figures in 100000 g?
Answer:
1
Explanation:
Any digit that is not 0 is always significant
Please tell me the answer of this question, first person to answer will be marked brainlist
the rays produced in a cathode tube are
Answer:
Electrons
Explanation:
Cathode rays carry electronic currents through the tube. Electrons were first discovered as the constituents of cathode rays. J.J. Thomson used the cathode ray tube to determine that atoms had small negatively charged particles inside of them, which he called “electrons.”
The rays produced in a cathode tube are electrons which are present in the shells surrounding the nucleus of an atom.
What is an atom?
An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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Explain why, at room temperature, CO2 is a gas and CS2 is a liquid. You may use diagrams as part of your explanation.
Explanation:
A. Hydrogen bonding is present in CS2 but not in CO2.
B. CS2 has greater dipole moment than CO2 and thus the dipole-dipole forces in CS2 are stronger.
C. CS2 partly dissociates to form ions and CO2 does not. Therefore, ion-dipole interactions are present in CS2 but not in CO2.
D. The dispersion forces are greater in CS2 than in CO2.
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If yuo put hand sanitizer in a bottle, light a match, drop it in the bottle, what will happen?
Answer: As hand sanitizer dries, it evaporates into gas, which can also catch fire. That’s why the experts recommend that people avoid lighters, matches and fires after using hand sanitizer.
Explanation:
Explanation:
A medida que se seca el desinfectante de manos, se evapora en gas, que también puede incendiarse. Es por eso que los expertos recomiendan que las personas eviten los encendedores, fósforos y fuegos después de usar desinfectante para manos.
when using a ph meter to monitor a stirring reaction mixture, where should you place the ph sensor electrode?
Answer:Between the stirring vortex and the side of the glassware
When using a ph meter to monitor a stirring reaction mixture, the ph sensor electrode
should be placed;
between the stirring vortex and the side of the glassware.
The pH meter is an electric device that is used to measure the hydrogen-ion activity in water-based solutions. This means that it is used to measure the PH which is the acidity or alkalinity.
The pH meter is made up of a voltmeter attached to a pH-responsive electrode and a reference electrode.
Now, this pH-responsive electrode is usually made of glass while the reference electrode is usually a silver–silver chloride electrode.
Now when monitoring the stirring reaction mixture, the PH-responsive electrode written above is usually placed between the stirring vortex and the side of the glassware.
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According to Democritus, which substance cannot be divided?
O A. molecules
O B. matter
O C. compounds
OD. atoms
Answer:
D.) Atoms.
I hope this helps! :)
How long should you monitor a person who shows signs of a mild allergic reaction
Answer:
Most reactions occur quickly after ingestion or contact with the allergen, but some can occur up to a few hours later. There can also be a second phase of the reaction when symptoms reoccur. It is important to keep an eye on your child for about 6-8 hours following the first reaction.
Explanation:
How would you change liquid water into ice? Be sure to explain what is happening to the energy (the heat)
Answer:
By putting the liquid water in the fridge
Explanation:
When it is solid the heat will melt to liquid water and if you put it inside a boiling kettle if it boil finished it will bring out gas,if you open it the cover of the kettle you see water if you put it in the fridge and it will be solid again.
The thermochemical equation for the formation of ammonia (NH3) is shown below. How much energy (kcal) is released when 6.0
mol of H2 reacts?
(Note - when the direction of energy flow is indicated, e.g. "released", the negative sign is not used in the answer.
3 H2(g) + N2(g) →2 NH3(g) triangleH = - 11 kcal
In the formation of NH₃, -22 kcal are released when 6.0 moles of H₂ react.
Let's consider the thermochemical equation for the formation of ammonia.
3 H₂(g) + N₂(g) → 2 NH₃(g) ΔH = - 11 kcal
As we can see, 11 kcal are released when 3 moles of H₂ react. The heat released when 6.0 moles of H₂ react is:
[tex]6.0molH_2 \times \frac{(-11kcal)}{3molH_2} = -22kcal[/tex]
In the formation of NH₃, -22 kcal are released when 6.0 moles of H₂ react.
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Carbon burns with oxygen to produce carbon dioxide gas.
Which of these shows the correct chemical reaction?
O C+0=CO2
O CO, CO2
C +02 + CO2
CO2 = C+0
Answer:
it will help you , but I am not sure it is correct
what happens to the pressure of a gas if its volume is reduced?
Answer:
When the volume decreases, the pressure increases. This shows that the pressure of a gas is inversely proportional to its volume. This is shown by the following equation - which is often called Boyle's law. ... It means that for a gas at a constant temperature, pressure × volume is also constant.
Explanation:
may i have the brainlyest
Answer:
When the volume decreases, the pressure increases. This shows that the pressure of a gas is inversely proportional to its volume. ... It means that for a gas at a constant temperature, pressure × volume is also constant.
Explanation:
why does the reaction of anthracene with maleic anhydride needs to be kept away from water?
Answer:
Water separates the two reactants into two layers, stopping the reaction.
Explanation:
Maleic anhydride can and will react with water.
The reaction between maleic anhydride and anthracene is a Diels Alder reaction. This type of reaction is a cycloaddition reaction.
What is Diels Alder reaction?The Diels Alder reaction is a member of a class of reactions called cycloadditions. This reaction involves three pi bonds, two from the diene and one from the dienophile in a concerted reaction to give a six-membered ring.
Since this reaction involves four pi electrons in the diene and two pi electrons from the dienophile, it is sometimes referred to as a 4+2 cycloaddition.
The presence of electron donating groups on the diene and the electron withdrawing groups on the dienophile favors normal Diels Alder reactions. The reaction involves the formation of new σ bonds which are energetically more stable than π bonds.
Anthracene can react with water, breaking the center ring. Maleic anhydride can react with water, opening its ring. The reactants get seperated into two layers by water and thereby stops the reaction.
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Compare and contrast Dalton's atomic theory with modern atomic theory.
Answer:
Postulates of Dalton's Atomic Theory:
1) Atoms can neither be created nor destroyed.
2) During chemical reaction, atoms combine or separate or re-arrange. They combine in simple ratios.
3) All elements are composed of the indivisible particles called atoms.
4) Atoms of a particular element are identical. They have the same mass and volume.
Postulates of modern atomic theory:
1) All matter is composed of atoms.
2) Atoms consist of protons, electrons and neutrons.
3) Atoms of an element may differ in masses. (as in isotopes)
4) The ratio in which elements combine may not be simple.
Similarities:
1) All elements/matter are/is composed of atoms.
2) Atoms can neither be created nor destroyed.
3) During chemical reactions, atom combine or separate or rearrange.
Differences:
1) Dalton's theory said that atoms are indivisible particles but modern theory denies it and calls atom a divisible particle consisting of sub-atomic particles, protons, electrons and neutrons.
2) Dalton's theory said that atoms of the same element have same mass and volume but according to modern theory, it is said that atoms of the same element can differ in mass (as in isotopes).
3) Dalton said that atoms combine in simple ratio but modern theory denies it.
[tex]\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807a space probe identifies a new element in a sample collected from an asteroid. successive ionization energies, in attojoules per atom, for the new element are given in the table. i1 i2 i3 i4 i5 i6 i7 0.507 1.017 4.108 5.074 6.147 7.903 8.294 to what family of the periodic table does this new element probably belong?
The element belongs to group 17 of the periodic table.
In the periodic table, elements are arranged in groups depending on their properties. Usually, elements whose atoms have the same number of valence electrons are placed in the same group.
All the elements in group 17 have seven electrons on their outermost shell. Since an ionization energies of the electrons on the valence shell of an atom are always close together, the ionization energies of the seven electrons as shown indicate that they must be on the same shell.
Hence, the new element must be a member of group 17 of the periodic table.
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The formation of a covalent bond involves the
Answer:
Atoms of non metals
Explanation:
Hope it helps!
How do I know the melting point and boiling point of each chemical?
What MUST always be true of the masses of the red and blue liquids?
А.
They will NEVER equal the mass of the purple liquid to the right of the arrow.
B.
They will ALWAYS equal the mass of the purple liquid to the right of the arrow.
The
6.
1. 0,005
5x10 3.
7.
2. 5,050
=
88104
8.
3. 0.0008 =
1 X 103
9.
4. 1,000 =
10
10
5. 1,000,000 =
Answer:
So the asnwer is 66666666666666666666666666666666666666666666666666666666666666666666666666666666666668888844444444444444444443299997832........................................................4563ygfdjuzgu3456655555555555555555555553444446445444444555554
Explanation:
when using vacuum filtration which type of tubing is best?
Answer:
The filter flask and the vacuum trap consist of heavy-walled glassware. You should use thick-walled tubings as well. Normal tubing that you use as water hoses will collapse under vacuum.
For vacuum filtration, thick walled tubings are best as they can withstand the pressure which is applied during filtration.
What is vacuum filtration?It is a filtration technique which works faster .This is because water is suck out the air in the vacuum flask and Buchner funnel by flowing it through the aspirator.
Filter at the bottom separates the solids from the liquids.Solid residue at top of funnel can be easily dried. The filtration takes place effeciently in presence of vacuum .
There is a rubber conical seal which ensures that the apparatus is hermetically closed,maintains vacuum in apparatus and avoids physical points of stresses.
Vacuum filtration is faster than gravity filtration and is more efficient leading to purer liquid. It is of much importance in crystallization.
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What happens when water reaches its boiling point?
Answer:
khi sôi nhiệt độ của nước đạt 100oC, đến lúc này một phần nước sôi sẽ biến thành hơi nước, hơi nước sẽ đùn lên phá vỡ mặt nước và bốc hơi vào không khí, hình thành lên hiện tượng sôi của nước. Nước sôi đánh dấu mốc chuyển đổi trạng thái từ nước (thể lỏng) sang hơi nước (thể khí).
Explanation:
Wavelength whose frequency is 5.00 x10^15
The wavelength of the radiation whose frequency is 5 X 10^15s^-1 is 2.4 X 10^-6 inches, or 60 nanometers.
what is the maximum wavelength of photon that will eject a ground state electron from a hydrogen atom?
Answer:
9.13 x 10^-8 m
Explanation:
The maximum wavelength of photon that will eject a ground state electron from a hydrogen atom is 9.18 * 10^-8.
What is wavelength?
Wavelength is defined as the distance between identical points in the adjacent cycle of a waveform signal propagated in space or along the wires.
Wavelength is calculated as wave speed and frequency.
Wavelength = speed/frequency
SI unit of wavelength is meter.
A ground state atom is an atom in which total energy of the electron can not be lowered by transferring one or more electrons to different orbitals.
Thus, the maximum wavelength of photon that will eject a ground state electron from a hydrogen atom is 9.18 * 10^-8.
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I will brainless who can answer this all pleaseeeeej
Answer:
False, True, True, False, False, not sure, True, False, True, True
here u go
Think of a time you might have used the scientific method without even realizing it.
Answer:
when i exist
Explanation:
When an electron in excited energy level drops to a lower energy
level, a photon is emitted.
If the electron is dropping to n=1, which transition will emit the longest
wavelength? n= ____ was to n=1.
The transition between n=1 and n=2 corresponds to the longest wavelength with the lowest frequency.
An electron is said to be "excited" when it is promoted to a higher energy level inside its bound state.
Either the electron absorbs a photon and obtains all of its energy, or it receives energy via a collision with another, energetic electron.
Understanding energy levels :
Therefore the transition between n=1 and n=2 corresponds to the longest wavelength at the lowest frequency.
The higher the frequency of a photon, the higher its energy.
The longer the wavelength of a photon, the lower its energy.
E ∝ 1/λ [ FOR PHOTON ]
The lowest energy is 1 eV, which corresponds to the transition between the n=1 and n=2 levels.
The longest wavelengths are associated with the lowest energies, so transitions between n=1 correspond to the longest wavelengths.
The term "thermal excitation" refers to the process by which electrons within a semiconductor crystal lattice are elevated to a higher energy band via lattice vibrations. This process, known as electron relaxation, occurs when an excited electron returns to a less energetic state.
As a result, a photon is released into the environment, or energy is transferred to another particle. The amount of energy released is proportional to the gap in potential energy between the electron's lowest and highest states.
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List some things that help with heat generation. What do you use everyday that helps with heat generation?
Answer: A toaster
Explanation: A toaster is an house held item that is used for heating and toasting bread and other stuff.
