Explanation:
Plant cells have several structures not found in other eukaryotes. In particular, organelles called chloroplasts allow plants to capture the energy of the Sun in energy-rich molecules; cell walls allow plants to have rigid structures as varied as wood trunks and supple leaves; and vacuoles allow plant cells to change size.
The cell wall is located outside the cell membrane. It consists mainly of cellulose and may also contain lignin , which makes it more rigid. The cell wall shapes, supports, and protects the cell. It prevents the cell from absorbing too much water and bursting.
What is known about a reaction with a negative enthalpy?
A. The reaction is endothermic,
B. The reaction is spontaneous,
C. The reaction is exothermic,
D. The reverse reaction is favored,
Considering the definition of enthalpy of reaction, the correct answer is option C. a reaction with a negative enthalpy indicates that the reaction is exothermic.
Definition of enthalpy of reactionThe enthalpy of a chemical reaction as the heat absorbed or released when chemicals are transformed into a chemical reaction and it occurs at constant pressure.
The enthalpy is an extensive property, that is, it depends on the amount of matter present.
Finally, it must be taken into account that:
A reaction is called exothermic if its enthalpy of reaction is negative (that is, if the system gives up heat).A reaction is called endothermic if its enthalpy of reaction is positive (that is, if the system absorbs heat).SummaryIn summary, a reaction with a negative enthalpy indicates that the reaction is exothermic.
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define SI unit system
Answer:
The SI base units are the standard units of measurement defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of Quantities: they are notably a basic set from which all other SI units can be derived.
H3C6H507 + H2O + H3O+ + H2C6H507
acid
base
Explanation:
an acid will give away a proton and become a conjugate base.
A base will accept a proton and become a conjugate acid.
9. a) Name salt that can be prepared by precipitation
I think its the substances that sublimes
what is the requirements to obtain citizenship?
please answer it correctly
Answer:
Age. ...
Residency. ...
Residence and Physical Presence.
Good Moral Character.
Attachment to the Constitution.
Language.
U.S. Government and History Knowledge.
Oath of Allegiance.
These are some requirements for obtaining citizenship .
In an electrochemical cell, equilibrium is the point at which:
A. None of these
B. both electrodes have an equal number of electrons.
C. ion concentrations are no longer changing and the voltage is 0.
D. Equilibrium cannot be reached in a voltaic cell because electrons only flow in one direction.
Answer:
C. ion concentrations are no longer changing and the voltage is 0.
Explanation:
Electrochemical cells are a device that generates current from redox reactions. In the cell, the equilibrium is reached when the voltage drops to 0. Thus, option C is correct.
What is an electrochemical cell?An electrochemical cell is a voltaic device that uses chemical energy to generate electrical energy and vice versa. It is of two types electrolytic and galvanic cells depending on the energy it produces.
The electrochemical cell comprises two electrodes namely an anode and cathode, a salt bridge or the porous barrier, and an external connection.
The connection shows the voltage that indicates the equilibrium. When the current flow stops and the voltage reaches zero, the electrochemical cell is said to be in equilibrium.
Therefore, no change in the ionic concentrations and zero voltage indicates equilibrium.
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which best describes nuclear energy?
A the energy that matter has due to the vibrations of its particles
B the energy an object has due to its chemical bonds
C the energy generated by a flow of electrons
D the energy stored inside the center of an atom
Answer:
The correct answer is - D. the energy stored inside the center of an atom.
Explanation:
Each atom has a small center in it called the nucleus and the energy that holds the nucleus or center of the atom together in the atom is known as nuclear energy.
It is the energy that is stored in the center of the atom and normally does not come out, however, in some radioactive atoms the sends some part of the energy as radiation.
Thus, the correct answer is - D. the energy stored inside the center of an atom.
precautive measures taken when using pooter
I guess ensuring that you don't suck the insects or specimen collected by ensuring there is a net in the pooter
what is the purest form of iron
what occurs when the vapor pressure of a lquid is equal to the external atmospheric pressure
Answer:
The change from a liquid phase to a gaseous phase occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid.
Explanation:
Boiling is a physical change and molecules are not chemically altered during the process.
A phase change from a solid to a gas is called:
Answer:
sublimation
Explanation:
Organisms do not adapt as a result of competition for resources.
Answer:
The given statement is False.
The organisms adapt as a result of competition for resources. Different places have different organisms suited for that particular places.
The animals living at a particular place compete for the resources available and the nature selects the organism that has won the competition for resources.
The organisms are evolved as a result of competition for resources
Answer:
I just wanted to say the other person is totally right.
this statement is false.
A sample of oxygen gas occupies a volume of 160 liters at 364 K. What will be the volume of the gas when the temperature drops to 273 K?
210 L
120 L
62 L
470 L
Answer:
62L
.
.
.
.
tysm.
.
.
.
.
hope it help
If an atom has three shell and number of valence electrons are two. Is this element metal
or non-metal and why? Name the element and it’s valency.
Answer:
Metal
Element: Calcium
Valency: 2
Explanation:
To find the element, let's use the periodic table. (Look below)
We already went past 3 shells, just need the 2 electrons after it.
Just skip to the 4th row and count 2 to the right
We end up at Calcium.
Calcium is a metal and we're also on the alkaline earth metals column.
Calcium will need to lose 2 electrons to reach stability, so the valency is 2.
describe an activity to separate the mixture of sand and water
Answer:
Sedimentation and decantation
Explanation:
Sedimentation and decantation: Mixture is kept undisturbed for some time. After some time, sand being heavier and insoluble in water, settles down at the bottom of container. Now, water is poured into another container to separate it from sand.
Answer:
evaporation or destillation
Explanation:
When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation.
Energy in the amount of 420 J is added to a 35 g sample of water at a temperature of 10°C. What is the final temperature of the water?
The final temperature of the water, T2 = 38.57°C
Temperature can be defined as a measure of the degree of hotness or coldness of a physical object (body). Thus, it is measured with a thermometer and its units are degree Celsius (°C), Fahrenheit (°F) and Kelvin (°K).
A calorie refers to the amount of heat required to raise the temperature of a gram of water by one (1) degree Celsius (1°C).
Given the following data:
Quantity of energy = 420JMass = 35 gramsInitial temperature, T1 = 10°CThe specific heat capacity of water is 4.2 J/g°C.
To find the final temperature of the water (T2):
Mathematically, the quantity of energy (heat capacity) is given by the formula;
[tex]Q = mcdt[/tex]
Where;
Q represents the heat capacity or quantity of heat.M represents the mass of an object.C represents the specific heat capacity of water.dt represents the change in temperature.Substituting the values into the formula, we have;
[tex]420 = 3.5 \; * \; 4.2 \; * \; dt[/tex]
[tex]420 = 14.7 \; * \; dt\\\\dt = \frac{420}{14.7}[/tex]
Change in temperature, dt = 28.57°C
Next, we would solve for the final temperature by using this formula;
[tex]dt = T2 - T1[/tex]
[tex]28.57 = T_{2} - 10\\\\T_{2} = 28.57 \; + \; 10\\\\T_{2} = 38.57[/tex]
Final temperature, T2 = 38.57°C
Therefore, the final temperature of the water, T2 is equal to 38.57°C
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PLS HELP WILL GIVE BRAINLIEST
it is a simple chemistry question
i thought F has 9 electrons, so why does this structure show 8 electrons.
Answer:
The IUPAC structure only shows bond pairs and lone pairs. In the flouromethane structure above, there is only one bond pair and three lone pairs of electrons. Therefore there is one electron remaining, but since it doesn't not make up a pair, it is ignored in the structure but theoretically it is present.
[tex].[/tex]
Answer:
therefore there is one electron remaining , but since it doesn't make up a pair . It is ignored in the structure but theoretically it is present .
what is plasma in chemistry
Explanation:
Plasma is an ionized gas, a distinct fourth state of matter. “Ionized” means that at least one electron is not bound to an atom or molecule, converting the atoms or molecules into positively charged ions.but plasma is present in human body too in a liquid form.
hope this helps you
have a nice day
Plz help me with this question
Drawing of water molecular formulas
1.Draw molecular structure of water
Answer:
Here is your answer. I hope it will help you .Aluminum hydroxide containing medicine is used for gastric why
Answer:
Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They may be used to treat these symptoms in patients with peptic ulcer, gastritis, esophagitis, hiatal hernia, or too much acid in the stomach (gastric hyperacidity).
Answer:
wow it's a very nice question
Câu 1: Trong các dung dịch sau, dung dịch nào làm quỳ tím đổi màu xanh?
A. HCl B. H2SO4 C. NaOH D. NaCl
Câu 2: Bazơ nào dưới đây là bazơ không tan?
A. KOH B. NaOH C. Cu(OH)2 D. Ca(OH)2
Câu 3: Trong các chất sau đây, chất nào không phải là muối?
A. HCl B. KCl
C. NaOH
C. Cu (OH)
A. HCl
what do you mean by acceleration due to gravity of a body is 10 metre per second square
Answer:
If a body is accelerated by 10m/s^2, it means that the body's speed (or velocity to be precise) is increasing by 10m/s every second. That is, if the initial ...
Which phrase correctly describes the molecular structure within a molecule?(1 point)
A the location of atoms, groups, or ions relative to one another and the number, type, and location of covalent bonds
B long, repeating chains of molecules
C the smallest fundamental unit of a compound that participates in reactions, represented by a bonded group of atoms
D the basic unit of a chemical element
Answer: A the location of atoms, groups, or ions relative to one another and the number, type, and location of covalent bonds
Explanation: I just took the assessment and in my notebook molecular structure has a definition that is literally answer A. Also I got it right lol.
help pls I will mark brainlest
Resources found in lithosphere: gold and iron etc
Resources found in atmosphere: Water vapor, gases etc.
Câu 6: Cho 4,2 gam este đơn chức no E tác dụng hết với dung dịch KOH ta thu được 4,76
gam muối natri. Vậy công thức cấu tạo của E có thể là:
Convert 15,000 seconds into minutes
Answer:
250 minutes
Explanation:
60 seconds = 1 minute
15000 secods = 15000 / 60
1500 secons = 250 minutes
Which statement best describes redox behavior in an electrochemical cell?
Electrons are produced at the copper rod.
Electrons flow from cathode to anode.
Reduction occurs at the zinc electrolyte.
Charges are balanced during redox.
Answer:
The last one
Explanation:
Charges are balanced in a redox reaction
A student wants to separate a mixture of salt and water in a laboratory (a) Describe how the student can obtain both salt and water from the salt solution
Answer:
okay so basically what you are being tested is if you know the difference between simple and fractional distillation and okay you can evaporate the mixture but you won't obtain water so you will use simple distillation to obtain both salt and water
A student in a lab holds an iron nail over an open flame, and no reaction occurs. The nail is then filed, creating small pieces of
iron shavings. These pieces burn brightly when placed over an open flame.
Which statement accurately identifies one of the changes that occurs as a physical or chemical change?
Formation of small pieces of iron shavings is a physical change whereas burning of pieces of iron shavings is chemical change.
Formation of small pieces of iron shavings is an example of physical change because it can be changed again into nail while on the other hand, burning of pieces of iron shavings on the flame is an example of chemical change because it can't change again into its original shape. Physical change is a change in matter which does not change the chemical properties of the matter whereas chemical change is a change in matter which change the chemical properties of the matter.
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Arrange the steps in order to describe how photons and carbon dioxide (CO2) contribute to the warming of Earth.
CO2 in the atmosphere absorbs infrared
photons.
CO2 in the atmosphere emits infrared photons back toward Earth.
Photons from the Sun strike Earth and become infrared photons.
Earth radiates infrared photons into the atmosphere
The Sun radiates sunlight (visible)
photons
The Sun radiates sunlight (visible) photons
Photons from the Sun strike Earth and become infrared photons.
Earth radiates infrared photons into the atmosphere
CO2 in the atmosphere absorbs infrared photons.
CO2 in the atmosphere emits infrared photons back toward Earth.
Certain gases are known to contribute towards global warming. Such gases are called greenhouse gases. The infrared rays from the sun are absorbed by these gases as they are re-emitted from the earth and re-emitted.
The sun radiates photons to the earth which is re-radiated into outerspace from the earth's surface. CO2 and other greenhouse gases absorbs these gases and re-emit them to the earth thereby causing a gradually rise in the temperature of the earth called global warming.
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