Answer:
20 degrees Celsius
Explanation:
How much energy is required to vaporize 14.27 grams of water at its
boiling point? *
Energy required to vaporize : 32.3 kJ
Further explanationThe heat to change the phase can be formulated :
Q = mLf (melting/freezing)
Q = mLv (vaporization/condensation)
Lf=latent heat of fusion
Lv=latent heat of vaporization
Mass of water = 14.27 g
Latent heat of vaporization ( boiling point of 100 ºC) : 2260 J/g
Energy required :
[tex]\tt Q=m.Lv\\\\Q=14.27\times 2260\\\\Q=32250.2~J\approx 32.3~kJ[/tex]
A student added 5 grams of calcium chloride, a white solid substance, to 15 grams of water at 220 C. Several observations were made and the student inferred that a chemical reaction occurred.
Which observation best supports the student's inference that a chemical reaction occurred?
Answer:
D
Explanation:
A The calcium chloride dissolves in solution
B The mass of the solution totals 20 g
C The temperature of the solution is 35 degrees
D The solution became lighter in color
The correct answer would be that the solution became lighter in color.
An increase in temperature can also be considered a sign of a chemical reaction but in this case, the dissolution of calcium chloride in water is in itself exothermic.
A change in the mass of the final solution could also be considered a sign of a chemical reaction but in this case, the total mass equals the addition of the individual masses of the reactant.
The dissolution of calcium chloride in water is not enough as evidence of a chemical reaction. Dissolution can be a physical change of which, the evaporation of the water would retrieve the solute.
A change in color, however, is one of the evidence to establish that a chemical reaction has occurred.
The correct option is D.
Which is the formula for iodine tribromide?
IBr
IB3
IBr3
I3Br
Answer:
the answer is c IBr3
Explanation:
The chemical formula for iodine tribromide is IBr₃ as it has 1 iodine and 3 bromine atoms.
What is chemical formula?
Chemical formula is a way of representing the number of atoms present in a compound or molecule.It is written with the help of symbols of elements. It also makes use of brackets and subscripts.
Subscripts are used to denote number of atoms of each element and brackets indicate presence of group of atoms. Chemical formula does not contain words. Chemical formula in the simplest form is called empirical formula.
It is not the same as structural formula and does not have any information regarding structure.It does not provide any information regarding structure of molecule as obtained in structural formula.
There are four types of chemical formula:
1)empirical formula
2) structural formula
3)condensed formula
4)molecular formula
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Which of the following correctly lists the organization of genetic material inside the cell?
A.
chromosomes → nucleus → genes → DNA
B.
DNA → genes → nucleus → chromosomes
C.
genes → DNA → chromosomes → nucleus
D.
nucleus → DNA → gene → chromosomes
Answer:
A
Explanation:
I got it in a test
What is the concentration of a stock solution if 20 mL was used to make 400 mL of a 1.44
M solution?
30 M
40 M
50 M
5M
Given :
Volume of stock solution, [tex]V_s = 20\ mL[/tex].
Volume of diluted solution, [tex]V_d = 400 \ mL[/tex].
Molarity of diluted solution, [tex]M_d = 1.44\ M[/tex].
To Find :
The concentration of the stock solution.
Solution :
We know, dilution factor is given by :
[tex]D.F=\dfrac{V_ {diluted}}{V_{stock}}[/tex] ....1)
and [tex]D.F= \dfrac{M_{stock}}{M_{diluted}}[/tex] ....2)
Putting volume in above equation, we get :
D.F = 400/20
D.F = 20
Putting value of D.F in equation 2) we get :
[tex]\dfrac{M_{stock}}{M_{diluted}} = 20\\\\M_{stock} = 20\times 1.44\\\\M_{stock} =28.8\ M[/tex]
The concentration of stock solution is nearest to 30 M.
Therefore, the correct option is 1) 30 M.
Choose the molecule with the strongest internal bond, (intra-, not intermolecular bond)
Answer:
A
Explanation:
The molecule with the strongest intramolecular bond is HF. Hydrogen fluoride is the answer due to the strong and highly electronegative nature of Fluorine.
Fluorine is the most electronegative element in nature. When it combines with other substances, due to its electronegative property, it draws most of the electrons closest to itself in the bond. This tendency and ability makes the shared electrons closer the fluorine in the bond. The strong polarization that ensues confers a very strong covalent bond pair on the bond formed.The molecule with the strongest internal bond is HF and the correct option is option A.
An intramolecular bond, also known as a chemical bond, refers to the attractive forces that hold atoms together within a molecule. It involves the sharing, transferring, or rearrangement of electrons between atoms to achieve a more stable configuration.
There are three primary types of intramolecular bonds:
Covalent Bond: In a covalent bond, atoms share electrons to achieve a more stable electron configuration. This bond is formed between nonmetal atoms.Ionic Bond: An ionic bond is formed when there is a complete transfer of electrons from one atom to another. It involves the attraction between positively and negatively charged ions. Ionic bonds typically occur between a metal and a nonmetal.Metallic Bond: Metallic bonding occurs in metals and is characterized by a "sea of electrons" in which the valence electrons are delocalized and free to move within the metal lattice. This allows metals to conduct electricity and exhibit other unique properties.Thus, the ideal selection is option A.
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What is the difference between active transport and facilitated diffusion?
Answer:
Active transport is an active process. Thus, it requires energy. Whereas facilitated diffusion is a passive process and does not require energy.
Explanation:
ugh
are Li, Na and K in the same group
Answer: Yes, they are.
Explanation:
Yes, they are. Li, Na, and K are referring to Lithium, sodium, and potassium.
They are all belonging to the same group which is called the alkali metals group.
They are having the same number of valence electrons i.e. 1.
This group of the alkali metals are considering tree more metals in it which are Rb, Cs, and Fr.
Please help me #6!!!!!!!!
PLEASE HELP!!!!
7. According to Mohs Hardness scale, which of these groups of minerals can scratch fluorite? А. B. talc, calcite, and apatite calcite, quartz, and topaz apatite, orthoclase, and corundum diamond, gypsum, and quartz C.
Answer:
B
IS THE CORRECT ANSWER
Which of these statements describes the basic idea of the Valence Shell
Electron Pair Repulsion (VSEPR) theory?
1. Molecules repel one another due to intermolecular forces.
2. There is always an octet of electrons around an atom in a molecule
3. Shared and unshared electron pairs repel each other as much as
possible
4. Electrons are attracted to the nucleus of the central atom.
Answer:
3. Shared and unshared electron pairs repel each other as much as
possible
Explanation:
The variations in the bond angles of molecules and ions can be explained using the valence shell electron pair repulsion theory.
The VESPR model determines the total number of electron pairs (TEP) surrounding the central atom of a specie. The TEP consists of bond pairs BP and lone pairs LP.
All the electron pairs will orient themselves in such a way as to minimize the electrostatic repulsion between them.
The repulsion determines the geometry of the covalent bonds around the central atom. As the number of lone pairs increases from 0 to 2, the bond angles diminishes progressively.
Which element is probably most like Carbon? and why
PLS PLS PLS HELP I WILL MARK YOU BRAINLYEST PLS
Answer:
A: Endoplasmic reticulum
B: Chroloplast
C: Mitochondrion
D: Cytoplasm
E: Cell wall
Explanation:
Agree or disagree
one rotation of the earth occurs everyday or 24 hours
Answer:
Agree
Explanation:
The rotation of earth happens about once every 24 hours.
can you pls help me with this question
Answer:
probably c
Explanation:
Answer: I feel like the correct answer is choice C but I really don’t know how to explain it..
Which statement correctly describes how a landform is created?
A canyon is created when ice from a glacier slowly melts over time.
A delta is created when wind blows large amounts of soil toward the shore
A sand dune is created when an earthquake breaks large rocks into small particles.
A V-shaped valley is created when a fast-moving river carves steep sides into hills and mountains
Plz I need help with this stuff!!!!!!!!!brainly wouldn’t let me post the other pics
Help plz 15 pointsss
Find the percent of water in Zn3(PO4)2 x 7H2O
Answer:
24.66%
Explanation:
To find the percent of water (H2O) in the following compound: Zn3(PO4)2. 7H2O
The atomic mass of the elements are as follows:
Zn = 65g/mol
P = 31g/mol
O = 16g/mol
H = 1g/mol
Hence, molar mass of the compound is as follows:
65(3) + {31 + 16(4)} 2 + 7{1(2) + 16}
195 + 95(2) + 7(18)
195 + 190 + 126
511g/mol
Molar mass of 7H2O
= 7(18)
= 126g/mol
Hence, the percent of H2O in the compound is:
Molar Mass of 7H2O/molar mass of compound × 100
= 126/511 × 100
= 0.2466 × 100
= 24.66%
Much of the earth’s heat is retained in the
crust.
wind.
oceans.
mountains.
1. An element is defined by the number of:
Electrons
Protons
Neutrons
Chemical Bonds
lons
Answer:
The correct answer for this question would be B) Protons
Explanation:
I got it right on my test (Can I have brainlyest)
What is the advantage of using Microsoft Excel to create a graph, as opposed to pen and paper?
Chemistry class I NEED HELP FAST
Answer:
the advantage of using Microsoft Excel to create a graph, as opposed to pen and paper is it will help you get the right answer
Explanation:
How many grams of CaCI2 (molar mass = 111 g/mol) are needed to prepare 100.mL of 0.100 M CI-(aq) ions?
a.) 0.555 g
b.) 1.11 g
c.) 2.22 g
d.) 5.55 g
I will mark as brainliest if you give the correct answer (brief explanation only, no worries)
Answer:
a
Explanation:
Because that is the answer
d) velocity ratio =_________ Iload distance
Answer:
velocity ratio is defined as the ratio of distance moved by effort and load in the same time interval
Explanation:
How many moles are in 2.91 x 10^22 molecules of Helium?
Answer:
0.048 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{2.91 \times {10}^{22} }{6.02 \times {10}^{23} } \\ = 0.048338...[/tex]
We have the final answer as
0.048 molesHope this helps you
As bond number increases (double bonds rather than single, triple rather than double etc.), bond length and bond energy . Group of answer choices Decreases, increases Decreases, decreases Increase, increases Increase, decreases
Answer:
Decreases, increases
Explanation:
Depending on the number of electrons shared, covalent bonds may be single, double or triple. In a single bond, two electrons are shared between bonding atoms. In a double bond, four electrons are shared between bonding atoms while in a tripe bond, six electrons are shared between bonding atoms.
The number of bonds is otherwise referred to as the bond order. The higher the bond order the higher the bond energy and the shorter the bond length. The bond length shortens due to an increase in the s character of the bond.
I WILL GIVE BRAINLEST IF YOU ANSWER THIS QUESTION QUICKLY!!!
what is an orbital?
Answer:
Electric Patterns and has many different variations.
Explanation:
Why do you see different stars in spring’s night sky than in fall’s night sky? Explain.
Answer:
If observed through the year, the constellations shift gradually to the west. This is caused by Earth's orbit around our Sun. In the summer, viewers are looking in a different direction in space at night than they are during the winter.
Explanation:
Answer:
there it the fact that the earthisspinningand so the starsare staying still and we are spinning
Plz help already late in turning it in
WILL GIVE BRAINLIEST (major help!!! need now!!!) David observed properties of four different compounds, only one of which is an ionic compound. His observations are shown in the chart.
A 2-column table with 4 rows. The first column labeled compound has entries W, X, Y, Z. The second column labeled observations has entries is a hard solid, melts at 44 degrees C, has a molecular structure; is a brittle solid, does not conduct electricity in water, has a crystal structure; is a hard solid, conducts electricity, has a molecular structure; is a brittle solid, melts at 801 degrees C, has a crystal structure.
Which is most likely the ionic compound?
W
X
Y
Z
Answer:
B. X
Explanation:
Answer:
The answer is D
Explanation:
Wave W is being diffracted, Wave X is being reflected, and waves Y and Z are being refracted.