Answer:
A heating curve graphically represents the phase transitions that a substance undergoes as heat is added to it. The plateaus on the curve mark the phase changes.The second change of phase is boiling, as the temperature stays the same during the transition to gas.
Explanation:
which statement accurately describes the reactants of a reaction?
Answer:
Option (B) is the correct answer.
Explanation:
Reactants are the species which are present on the left hand side of a chemical equation.
On the other hand, products are the species which are present on the right hand side of a chemical equation.
For example,
Here, NaCl and H_{2}O are the reactants whereas NaOH and HCl are the products.
This also means that products are the new substances which are formed.
Thus, we can conclude that new substances that are present at the end of a reaction accurately describes the products of a reaction.
the one that accurately describes the products of a reaction is : B. new substances that are present at the end of a reaction
For example the process of photosynthesis transform CO2 and other nutrients into O2 and H2O
Answer:
I think its substances that are used up
Explanation:
An element with 7 valence electrons will most likely
Answer:
An element with 7 valence electrons will most likely be a halogen and gain an electron
Explanation:
The element with 7 valence electrons is a halogen. Halogen group contains fluorine, chlorine, bromine, iodine and astatine.
What are halogens?Halogens are 17th group elements in periodic table. They are gases and shows high electronegativity. Halogens are p block elements.
The group number in periodic table is given assigned by adding 10 to the number of valence electrons if the no of valence electrons is 3 or more. Elements containing 1 or 2 valence electrons are in group 1 and 2 respectively.
Thus, if the number of valence electron 7 then, the element is in group 17 and it is a halogen.
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3. How does the independent variable (IV)
differ from the dependent variable (DV)?
Answer:
Independent variable in independent where the dependent variable relays on the independent one.
Explanation:
Look in the names and above.
If you squeeze a foam pillow, what kind of energy are you increasing in the foam?
Group of answer choices
Nuclear energy
Sound energy
Chemical energy
Elastic energy
Answer:
elastic energy
Explanation:
If you squeeze a foam pillow, elastic energy is increasing in the foam. Therefore, option D is correct.
What is elastic energy?Elastic energy can be described as the mechanical potential energy stored in the physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy takes place when objects are impermanently compressed, stretched, or deformed.
Elasticity theory develops formalisms for the mechanics of solid bodies and materials. The elastic potential energy can be used in mechanical equilibrium. The energy can be described as potential as it will be transformed into other forms of energy.
[tex]{\displaystyle U={\frac {1}{2}}k\,\Delta x^{2}}[/tex]
Forces applied to elastic transfer energy into the material yield energy to its surroundings and can recover its original shape. Materials have limits to the degree of distortion can without breaking or irreversibly altering their internal structure.
The elastic energy of a substance can be defined as the static energy of configuration. It refers to the energy stored by changing the interatomic distances between nuclei.
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Hector went to the grocery store by heading due north at 3 m/s, then turning east and continuing at
the same speed for another three blocks. Which of the following is true about Hector's velocity?
A. Hector's velocity did not change because his direction did not change.
B. Hector's velocity changed because his speed changed.
C. Hector's velocity changed because his direction changed.
D. Hector's velocity did not change because his speed did not change.
Hector's velocity changed because his direction changed.
Velocity refers to the distance covered per unit time in a specified direction while speed is the distance covered per unit time without taking the direction into account.
We must note that Hector's direction changed. since magnitude and direction are both considered when discussing velocity, then Hector's velocity changed because his direction changed.
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Which of the following is not an example of temperature abuse ?
A student dissolves 10,3 g of sodium chloride(NaCl) in 250 g of water in a well-insulated open cup. She then observes the temperature of the water fall from 23.0 °C to 22.2 °C over the course of 3 minutes. Use this data, and any information you need from the ALEKS Data resource,
NaCl (s) rightarrow Na+ (aq) + Cl- (aq)
You can make any reasonable assumptions about the physical properties of the solution. Note for advanced students: it's possible the student did not do the experiment carefully, and the values you calculate may not be the same as the known and published values for this reaction.
1. Is this reaction exothermic, endothermic, or neither?
2. If you said the reaction was exothermic or endothermic, calculate the amount of heat that was released or absorbed by the reaction in this case.
3. Calculate the reaction enthalpy delta Hrxn per mole of NaCl.
Answer:
1
The reaction is exothermic
2
[tex]H = -1.1 \ KJ[/tex]
3
[tex]\Delta H_{rxn} = -6.24 \ KJ/ mol[/tex]
Explanation:
From the question we are told that
The mass of the sodium chloride is (NaCl ) is [tex]m_s = 10.3 \ g[/tex]
The mass of water is [tex]m_w = 250 \ g[/tex]
The initial temperature is [tex]T_i = 23^oC[/tex]
The temperature after 3 minutes is [tex]T_3 = 22.2 ^oC[/tex]
The time taken for temperature to fall is t = 3 minutes
The reaction is
[tex]NaCl_{ (s)} \rightarrow Na^+ _{(aq)} + Cl^-_{ (aq)}[/tex]
The reaction is exothermic because the temperature fell
Generally the mass of the solution is mathematically represented as
[tex]M = m_w + m_s[/tex]
=> [tex]M = 250 + 10.3 [/tex]
=> [tex]M = 260.3 \ g [/tex]
Gnerally the heat energy released from the solution is mathematically represented as
[tex]H = M * C_s * (T_3 - T_i)[/tex]
Here [tex]C_s[/tex] is the specific heat of solution which for this question we would assume it is the specific heat of water which has a value of
[tex]Cs = C_w = 4.18 J/g^oC[/tex]
So
[tex]H = 260.3 * 4.18 * (22- 23)[/tex]
[tex]H = -1088.054 \ J[/tex]
[tex]H = -1.088054 \ KJ[/tex]
[tex]H = -1.1 \ KJ[/tex]
Generally the number of moles of NaCl is mathematically represented as
[tex]nNaCl = \frac{m_s}{zNaCl}[/tex]
Here [tex]zNaCl[/tex] is the molar mass of NaCl and the value is
[tex]zNaCl = 58.44 \ g/mol[/tex]
So
[tex]nNaCl = \frac{10.3}{58.44 }[/tex]
=> [tex]nNaCl = 0.1762 \ moles[/tex]
Generally reaction enthalpy is mathematically represented as
[tex]\Delta H_{rxn} = \frac{H}{nNaCl}[/tex]
[tex]\Delta H_{rxn} = \frac{-1.1}{0.1762 }[/tex]
[tex]\Delta H_{rxn} = -6.24 \ KJ/ mol[/tex]
Consider the following isotopic abundance data for argon (Ar) and silicon (Si):
Argon Isotope Isotopic Molar Mass 36 Ar 35.96755 g/mol Ar 37.96272 g/mol 40 Ar 39.96240 g/mol Abundance 0.337% 0.063% 99.600% Silicon Isotope Isotopic Molar Mass 25 Si 27.97693 g/mol 29 Si 28.97649 g/mol 30 Si 29.97376 g/mol Abundance 92.23% 4.67% 3.10%
Use the data to calculate the atomic masses of naturally occurring argon and silicon.
b) Calculate the number of atoms in 78.2 g of naturally occuring Si.
c) 42Ar is one of the longest lived radioactive isotopes of Argon. Mass spectroscopy data yields the following ratio of the mass of 42Ar to 40Ar: Mass of 42Ar Mass of 40Ar = 1.05006 use this ratio to find the atomic mass of 42Ar.
2. Pantoprazole, first sold under the brand name Protonix, is used for short-term treatment of erosive esophagitis associated with gastroesophageal reflux disease (GERD). The chemical formula for pantoprazole is C16H15F2N3O4S a) What is the molar mass of pantoprazole? b) How many molecules are in a 0.078 g sample of panotprazole?
Answer:
Explanation:
Molar mass of Argon
= 35.96755 x .00337 + 37.96272 x .00063 + 39.96240 x .99600
= .12121 + .0239165 + 39.80255
= 39.95
Molar mass of silicon
27.97693 x .9223 + 28.97649 x .0467 + 29.97376 x .0310
= 25.803 + 1.35320 + .929
= 28.08
b )
No of atoms of Si in 78.2 g = 78.2 x 6.02 x 10²³ / 28.08
= 16.76 x 10²³ .
c )
42 Ar / 40 Ar = 1.05006
42 Ar / 39.95 = 1.05006
42Ar = 41.95
2 )
C₁₆H₁₅F₂N₃O₄S
Mol weight = 16 x 12 + 1 x 15 + 2 x 19 + 3 x 14 + 4 x 16 + 32
= 192 + 15 + 38 + 42 + 64+ 32
= 383
No of molecules = .078 x 6.02 x 10²³ / 383
= 1.226 x 10²⁰ molecules .
Answer:
It's too short. Write at least 20 characters to explain it well.
Explanation:
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Which type of microscope can be used to view atoms
Answer:
transmission electron microscope
Explanation:
Answer:
Scanning tunneling microscope
Explanation:
What is the minimum number of significant digits in 828,000,000
Answer:
Answer:
Number of Significant Figures: 3
The Significant Figures are 8 2 8
Explanation:
you welcome
a chemist has a jar containing 388.2 g of iron fillings. how many moles of iron does the jar contain?
Why is it difficult to hold and keep liquids like water in your hand? Guys please help
Answer:
Molecules move freely around since they don't have a definite shape. This is the reason water stays liquid and couldn't be gripped.
what are the real primary colors
Answer:
red, yellow, blue are the 3 main primary colors
If an atom contains 11 protons and 12 neutrons, its ATOMIC NUMBER is: a 1 b 11 c 12 d 23
Answer:
B)11
Explanation:
The atomic number is the number of protons and electrons in an atom!!
HOPE THIS HELPS!!!!!!
Which characteristic is expected of a mineral that crystallizes from lava at Earth’s surface?
large crystals
small crystals
magnetic crystals
hexagonal crystals
Answer:
Small Crystals
Explanation:
Answer:
the answer is B
Explanation:
A sample containing 16.93 metal pellets is poured into a graduated cylinder containing 11.2 of water, causing the water level in the to 19.7 Calculate the density of the metal.
Blank = g/ml
Answer:
The answer is 1.99 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 16.93 g
volume = final volume of water - initial volume of water
volume = 19.7 - 11.2 = 8.5 mL
We have
[tex]density = \frac{16.93}{8.5} \\ = 1.9917647058...[/tex]
We have the final answer as
1.99 g/mLHope this helps you
What is an organ? List five (5) examples of organs?
Answer:
Here are all of the organ systems with some examples of organs found in each system:
Integumentary (skin, hair, nails)
Skeletal (bones)
Muscular (smooth, cardiac, and skeletal muscles)
Circulatory (heart, arteries, veins)
Respiratory (lungs, diaphragm, larynx)
Digestive (stomach, intestines, liver)
Explanation:
Zachary adds 26.64 g to 12.557 g. How many significant figures should his answer have?
two
three
four
five
This answer should have four signifigant features
Explanation:
I had this on a test and got it right :D
Students are given a solid sample and asked to determine whether the sample is an element, compound, or mixture. One student observes that the sample is:
made up of particles of different colors, sizes, and shapes
some particles are softer than others
some shine while others appear dull
What can the students conclude about their sample?
It is an element.
It is a compound.
It is a homogeneous mixture.
It is a heterogeneous mixture.
Answer:
Compound
Explanation:
The sample given to the students is a mixture.
A mixture is composed of substances that are not chemically combined together. The components of a mixture all retain their individual properties. So in a mixture, we can easily notice the individual components if the mixture is heterogeneous.
Clearly, the students were given a heterogeneous mixture because one student observed that the sample is;
made up of particles of different colors, sizes, and shapes some particles are softer than others some shine while others appear dullBased on these observations, other students can agree that the sample is a mixture.
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Calculate the wavelength of light with an energy of 3.60x10^-19 J *
Explanation:
from E = mc^2 and de Broglie wavelength=h/mc
combine the eqns with respect to m(considering the body is moving with the speed of light(c))
then
E= hc/de Broglie wavelength
since, c= 3× 10^ 8
h= 6.626 × 10^ -34 and E is given, substitute the values.
sorry I don't have my calculator.
no one ever helps me ☹️ can y’all look at my questions !?
Answer:
[tex]Hope this helps you[/tex] A typical atom consists of three subatomic particles: protons, neutrons, and electrons (as seen in the helium atom below). Other particles exist as well, such as alpha and beta particles (which are discussed below). The Bohr model shows the three basic subatomic particles in a simple manner. Most of an atom's mass is in the nucleus—a small, dense area at the center of every atom, composed of nucleons. Nucleons include protons and neutrons. All the positive charge of an atom is contained in the nucleus, and originates from the protons. Neutrons are neutrally-charged. Electrons, which are negatively-charged, are located outside of the nucleus. [tex]Enjoy your day[/tex]
Explanation:
Answer:
Atoms are the fundamental building blocks of all matter and are composed of protons, neutrons, and electrons. Because atoms are electrically neutral, the number of positively charged protons must be equal to the number of negatively charged electrons. Since neutrons do not affect the charge, the number of neutrons is not dependent on the number of protons and will vary even among atoms of the same element.
Explanation:
hope it helps
What Types of food molecules make up lettuce
Which is most likely a covalent compound?
LiF
MgS
NH3
CaCl2
Answer:
NH3 is the most likely covalent compound
Explanation:
Other Choices are:
LiF- Ionic compound
MgS- ionic compound
CaCl2- ionic compound
The most likely to have a covalent bond is NH₃. The correct option is c. covalent bonds are the strongest bonds among all.
What are covalent bonds?A covalent bond is formed between two atoms by the mutual sharing of one or more pairs of electrons. The two atomic nuclei attract these electrons at the same time. When the difference in electronegativities of two atoms is too tiny for electron transfer to produce ions, a covalent bond occurs.
The unequal sharing of electrons between the combining atoms results in the formation of a polar covalent bond. The equal sharing of electrons between the combining atoms results in the formation of a non-polar covalent bond.
LiF- Ionic compound
MgS- ionic compound
CaCl₂- ionic compound
Therefore, the correct option is c, NH₃.
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Which of the following describes a net force?
It is the total of the combined forces acting on an object.
It is the same thing as gravity.
It is a force that is part of the Internet.
It is the same thing as inertia.
Answer:
Net force is the vector sum of forces acting on a particle or body. ... Its associated torque, the net force, becomes the resultant force and has the same effect on the rotational motion of the object as all actual forces taken together.
Carbon -11 is a radioactive isotope of carbon. It’s half life is 20 minutes. What amount of the initial mass of 70.0g of C -11 atoms in a sample will be left after 80 minutes
Answer:
4.38g
Explanation:
70.0/2 = 35g - 20 mins
35/2 = 17.5g - 40 mins
17.5/2 = 8.75g - 60 mins
8.75/2 = 4.375g - 80 mins
4.375 g of the carbon 11 would be remaining after 80 minutes.
Half life is the time taken for a substance to decay to half of its original value. It is given by:
[tex]N(t)=N_o(\frac{1}{2})^{\frac{t}{t_\frac{1}{2} } } \\\\\\Where\ t_\frac{1}{2}\ is\ half\ life,N_o\ is\ original\ amount,t\ is\ time,N(t)\ is\\amount\ remaining\\\\\\Given\ that\ N_o=70,t_\frac{1}{2}=20,t=80, hence:\\\\N(t)=70(\frac{1}{2} )^\frac{80}{20}=4.375\ g[/tex]
Therefore, 4.375 g of the carbon 11 would be remaining after 80 minutes.
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A small bottle of water is left on the shore of a very large lake on an extremely cold winter night. What is most
likely to be observed the next morning? A). Both the lake and the bottles of water have become solid. B). The bottle of water has become solid but the lake has not. C). The lake has become solid but the bottle of water has not. D). Neither the bottle of water or the lake have become solid.
Answer:
A
Explanation:
Because it is a cold winter night making the lake freeze and the bottle is already solid.
Which phase has the greatest structure
Answer:
The answer is D
Explosion:
it depends on the solid,liquid,gas and the tempcher
An organic solvent has a density of 1.31 g/mL. What volume is occupied by 57.5 g of the liquid?
mL
Answer:
The answer is 43.89 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass = 57.5 g
density = 1.31 g/mL
We have
[tex]volume = \frac{57.5}{1.31} \\ = 43.89312977...[/tex]
We have the final answer as
43.89 mLHope this helps you
Chlorine is made up of 75.78% 35cl and 24.22% 37 cl. The atomic mass of 35 CL is 34.969 amu. The atomic mass of 37 CL is 36.966 amu. What is the average atomic mass of a sample of chlorine?
35.453 amu is the correct answer
Calculate the percent composition by mass of each element in LiClO2.
Given parameters:
Chemical specie = LiClO₂
Unknown:
Percentage composition of each specie = ?
Solution:
The percentage composition involves knowing the percent of total mass of a compound is made up of each of the constituent elements or groups.
Sum up the atomic masses and find the formula massDetermine percentage composition of each elementFormula mass of LiClO₂;
7 + 35.5 + 2(16) = 74.5g/mol
The percentage composition of each species are;
%Li = [tex]\frac{7}{74.5}[/tex] x 100 = 9.4%
%Cl = [tex]\frac{35.5}{74.5} x 100[/tex] = 47.7%
%O₂ = [tex]\frac{32}{74.5} x 100[/tex] = 43.0%