Answer:
45 grams
Explanation:
when it is time to end a reflux, first choose... and then turn off the heat. choose... until the system has cooled.
Answer:
second one is better
Explanation:
system is very much hot in first state..so wait for cooling down the system..but these depend on the organic compounds and products you are using. sometimes we need to carryout further steps in hot state..then you can't wail it to cool down
Please help I am stuck on this question
i think the answer is nervus cell because they work togtter to form the brain
What can affect the properties of a substance?
neither the arrangement nor the types of atoms
only the types of atoms
the arrangement and types of atoms
only the arrangement of atoms
What are the ways that heat transfers? identify common examples of heat transfer.
Answer:
Conduction is the process of heat being transferred between objects through direct contact, and it's the most common type of heat transfer. For example, in cooking the burners on stoves will conduct heat energy to the bottom of a pan sitting on top of it. From there, the pan conducts heat to its contents.
Explanation:
What is true of a saturated solution?
Answer:
A saturated solution is a solution that contains the maximum amount of solute that is capable of being dissolved. At 20°C, the maximum amount of NaCl that will dissolve in 100. g of water is 36.0 g. If any more NaCl is added past that point, it will not dissolve because the solution is saturated.
Copy and complete the concept map using the following:
(Na, Fe, actinides, Hg, Cs, Alkali, Inner transition)
Answer:
a) Alkali
b) Na
c) Cs
d) Inner Transition
e) actinides
f) Fe
g) Hg
Explanation:
K, Na and Cs are all Alkali MetalsFe, Hg and Ag are all Transition Metalsactinides and lanthanides are known as the Inner Transition Metalhow many valence electrons does P have?
Answer:
5 valence electrons
Explanation:
Phosphorus is in group VA so it has 5 valence electrons and Oxygen is in group VIA so each oxygen has 6 valence electrons.
what is the characteristics of crystals
what is the number of neutron in an atom of 86Kr
Answer:50
Explanation:
Kr has 36 protons because that is its atomic number. Simple subtraction from the given AMU gets 50 protons. ([tex]86-36=50[/tex])
Answer:
Neutron Number (N) 50
(I think)
Which statement best describes a physical change?
1 Changes can occur to certain chemical properties of the substance, but the overall shape of the substance will remain the same.
2 Changes can occur to certain physical properties of the substance, but the overall shape of the substance will remain the same.
3 Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same.
4 Changes can occur to chemical properties of a substance, but the chemical composition of the substance remains the same.
Answer: 3 Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same
Explanation:
Physical change mainly physical properties of a substance while the chemical changes remain unchanged. Once there is a change to the chemistry of the substance, this would be classified as a chemical change.
This photo shows two objects: the lead in a pencil and a mineral sample.
Both are made of the element carbon. Which statement about these objects
must be true?
A. They contain the same number of atoms
B. They have the same mass
C. They consist of a single type of atom
D. They take up the same amount of space
PLS hurry I’ll give brainlist!! :>
how do ions form bonds, and describe the structure of the resulting compound.
Answer:
Electrons are transferred between atoms together in the ionic compound. The ions are arranged in a regular repeating pattern in an ionic crystal
Explanation:
Ions electrostatically attracts its counter ions and forms the ionic bond between these ions. The structure of ionic compounds depends on the number of atoms and bonded pair of electrons.
What is ionic bonding ?Ionic bonds are formed between metals and non-metals. Metals are electron rich and easily loss one or more electrons to the electron deficient non metals.
The loss of electrons make the atom forms a positive ion called cations. The gain of electrons make the formation of anions or negative ions. These positive ions and negative ions attracts electrostatically and forms ionic bond between them.
The structure of ionic compounds depends on the number of bonded atoms, size, presence of lone pairs etc. In solution ionic compounds exists as separate ions.
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Help me have no frewnds
People who have certain lung diseases, such as emphysema or lung cancer, often have to use oxygen from tanks. A large volume of oxygen can be put into a small tank because oxygen is a gas, and gases can be_________.
Answer:
I believe the answer is compressed
Explanation:
The answer may be a slightly different word, but if it's looked at by a human and not a robot compressed should work too
Gases can be compressed by applying high pressure. Thus large volume of oxygen can be contained in a tank by compressing the gas with high pressure.
What are gases?Gases are substances in state where its molecules are located far apart and are able to spread in the surroundings. This property of spreading based on the concentration difference is called diffusion.
Thus, gases diffuse from high concentrated area to lower concentration region. Gaseous substances does not have a certain volume, mass or shape. But when they are collected into a container then the volume will be that of the container.
in liquid state, molecules are some more closer in comparison to gases and an intermolecular attraction of force bind these molecules together to have a certain volume and mass. Whereas in solids, all the molecules are tightly packed.
Gases can be liquified by applying high pressure at low temperature so that the distance between molecules can be decreased and an intermolecular force of attraction occurs there.
So that large volume of gases can be collected to a tank by compression using high pressure.
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Someone pls help me I will make you brain
Answer:
human migration
Explanation:
Answer:
I think its D
Explanation:
Which of the following is an example of chemical energy being used?
(A) Battery in a flashlight
(B) Ice melting
(C) Riding a bicycle
(D) Mercury rising in a thermometer
Answer:
(A) Battery in a flashlight
Explanation:
Because the chemicals in the battery are being converted to light and heat energy from the bulb!
Answer: D
Explanatione: I hope this helped :)
a sample of double-stranded dna contains 42% cytosine. approximately what percent of the nucleotides in this sample will be thymine?
Answer:
8% thymine
Explanation:
The percent of thymine in the given sample of the DNA will be equal to 8 %.
What is the structure of DNA?DNA, according to Chargaff, is composed of nucleotide subunits. These nucleotides are linked through two or more hydrogen-bonded to one another to form the double-stranded molecule of DNA.
The nucleotides found in the DNA molecule are Adenine, Thymine, Cytosine, and Guanine. Guanine (G) pairs with Cytosine (C) while Adenine (A) pairs with Thymine (T).
According to Chargaff's rule, the amount of Adenine is equal to that of Thymine in a DNA molecule and the same applies to Guanine and Cytosine. We can consider that the total amount of nucleotides equals 1 or 100%.
[tex]A + T + G + C = 100\%[/tex]
If Cytosine is 42 % of the DNA sample, this means that guanine will also be 42%.
G + C = 42 + 42 = 84%
A + T = 100% - 84 % = 16%
This means that Adenine and Thymine amount to 16 %. The amount of each nucleotide will be 16% ÷ 2 = 12% i.e. A = T = 8 %
Therefore, the percent of thymine in the given sample of the DNA will be 8 %.
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the modern model of the atom shows that electrons are:
. How many grams of water would require 4400 joules
of heat to raise its temperature from 34°C to 100°C?
The specific heat of water is 4.18 J/g.C
Answer:
The specific heat of water is 4.18 J/g C.
Explanation:
q
=
m
C
s
Δ
T
Never forget that!
2200
=
m
⋅
4.18
J
g
⋅
°
C
⋅
66
°
C
∴
m
≈
8.0
g
Arrange in the correct order of occurrence. Write 1 – 5 for each statement.
___ Magma cools and sinks.
___ Rocks are heated and melt.
___ Magma expands and rises at divergent boundaries.
___ Some magma move sideways in opposite directions.
___ Subduction in convergent boundaries make plates to reach the mantle
Answer:
Explanation:Rocks are heated and melt.
Some magma move sideways in opposite directions.Magma cools and sinks.Magma expands and rises at divergent boundaries.Magma expands and rises at divergent boundaries.
This image shows electronegativities of elements on the periodic table. Based on this information, which element is most likely to form a strong ionic bond and take on electrons?
(1 point)
helium (He)
cesium (Cs)
fluorine (F)
hydrogen (H)
Answer:
The answer is C. Fluorine.
Compare and contrast how light acts as a wave and as a particle
here you go
Explanation:
the flow of photons is a wave. ... The various properties of light, which is a type of electromagnetic wave, are due to the behavior of extremely small particles called photons that are invisible to the naked eye
Q4. What are the different ways in which human being use rocks ?
Answer:
To hit someone on the head
Explanation:
self protection
CHEMMMMMMMMM HELPPPPPP PLEASEEEE
Answer:
: \large \boldsymbol {\rm x > 5 \ or \ x\in (5\ ; \ \infty ) }x>5 or x∈(5 ; ∞)
Step-by-step explanation:
\begin{gathered}\large \boldsymbol {} \displaystyle -2(3x+2) > -8x+6 \\\\ -6x-4 > -8x+6 \\\\ 8x-6x=6+4 \\\\ 2x > 10 \\\\ x > 5 \ or \ x\in (5\ ; \ \infty )\end{gathered}
−2(3x+2)>−8x+6
−6x−4>−8x+6
8x−6x=6+4
2x>10
x>5 or x∈(5 ; ∞)
Investigation of ions and Separation of Mixtures 1- Propose systematic schemes for the identification of the following salts with respect to their anions and cations: NaCl, KNO3, and CuSO4?
The cations and anions can be identified using cataloged reactions schemes. For instance, the copper II ion can be identified by reaction with sodium hydroxide.
The sodium cation is easily identified by flame test. sodium imparts a yellow color to a flame. The chloride ion is identified by the use of a mixture of HNO3/AgNO3 solution. The color of the precipitate shows which halide ion is present. A white precipitate indicates the presence of the chloride ion.
The potassium cation is also identified by flame test. The ion imparts a lilac color to flame. Addition of acidified FeSO4 solution is used to confirm the presence of the nitrate ion. Formation of a brown ring is a positive test for the nitrate ion.
For CuSO4, the presence of copper II ion can be confirmed using dilute NaOH. If a light blue precipitate is formed which dissolves in excess NaOH then the copper II ion is confirmed. The presence of the sulfate ion is confirmed using a solution of barium nitrate and dilute nitric acid. Formation of a white precipitate is a positive test for the sulfate ion.
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Bernice created a table using her knowledge of charged and uncharged objects. Which statement best explains why the table is incorrect?
Charged Object Uncharged Object
Negatively charged attract
Positively charged repel
The negatively charged and uncharged objects do not attract.
A positively charged object attracts an uncharged object.
Both positive and negative charges repel uncharged objects.
An uncharged object neither attracts nor repels charged objects.
Answer:B
Explanation:
A positively charged object attracts an uncharged object.
A positively charged object attracts an uncharged object statement is in correct in the table. Hence option B is correct.
What are charge?Charge are defined as a subatomic particle's ability to experience force when exposed to an electric and magnetic field. The value that the atom reaches after removing or gaining electrons is known as charge. Only ions that comply with the octat rule are stable. Atoms or groups of atoms with an electric charge are referred to as ions. Cations are positive-charged ion particles. Anions are ion types that have a net negative charge.
A charged object will cause an opposing charge to be applied to an uncharged object when it is brought close to the charged one. These two things are drawn to one another because opposing charges attract one another. Other charged items are drawn to a charged object whereas uncharged objects are repelled by it.
Thus, a positively charged object attracts an uncharged object statement is in correct in the table. Hence option B is correct.
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Substances like liquid mercury are very ______, but substances like rubber are very _______
Answer:
electrons form the atoms f one material may move to the atoms of the other material. The movement of electrons from one atom to another changes the charge of the atoms. When an atom loses electrons, it is left with more protons than electrons, so it then has a positive charge. when an atom gains electrons, it has more electrons than protons so its charge is negative.
Explanation:
Convert 15.0 grams of H2 to molecules of H2.
What are the three zones in almost all human cells?
O cytoplasm, mitochondria, plasma membrane
O ribosomes, genetic material, cytoplasm
O nucleus, cytoplasm, plasma membrane
O mitochondria, genetic material, plasma membrane
In a molecule, how do we show what types of atoms are there and how many atoms there are of each type.