Answer:
Skin cells are flat and protect you!
Explanation:
Answer:
Epithelial cells are the safety shields of the body. Take another look at your hand. It is covered with epithelial cells that protect your body by being a barrier between your internal cells and the dirt and microbes in the environment.
A student draws a model of one of the sun's layers. The student draws arrows to represent hot gas moving away from the center of the sun and other arrows to represent cool gas moving toward the center of the sun. Which layer does the model show?
Radiation Zone
Convection Zone
Chromosphere
Inner Core
Answer:
The convection zone :)
4. What is a common cause of acid rain?
Answer:
Exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These can cause acid rain.
Hope this helps! :)
I need help with the question below
Answer:
D po
Explanation:
Sana nakatutulong
#Carry on learning
Pa brainliest po
A mystery element has 18 protons. Which one of the following statements is true about the element?
a.The element belongs in row 2 of the periodic table and is classified as a halogen.
b.The element belongs in row 3 of the periodic table and is classified as a noble gas.
c.The element belongs in row 4 of the periodic table and is classified as an alkali metal.
d.The element belongs in row 5 of the periodic table and is classified as an alkaline earth metal.
Answer:
its aragon , so letter b is right
Explanation:
Which of the following is the equation for wave speed?
Answer:
[tex]{ \boxed{ \mathfrak{ \: answer : \: { \bf{v = f \lambda}} }}}[/tex]
v is the wave speedf is frequencylambda is wave lengthWhat is an activation energy
Answer:
Defination of Activation energy :- In chemistry and physics, activation energy is the minimum amount of energy that must be provided for compounds to result in a chemical reaction. The activation energy of a reaction is measured in joules per mole, kilojoules per mole or kilocalories per mole. Meaning of Activation energy :- The minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction.Explanation:
Hope this helps you dear ✌️Carry on learning !!need help w this question
Answer:
ok you got it you just need to add.
Explanation:
add 5 times and she what you get.
What happens during liquefaction?
Answer:
it becomes water of it liqud
Explanation:
il explain in comment if you brainly me
Element X is in group 2, and element Y is in group 7, of the periodic table. which ions will be present in the compound formed when X and Y react together?
A) X^+ and Y^-
B)X^2+ and Y^-
C)X^+ and Y^2-
D)X^2- and Y^+
Answer:
Element X has valency 2 while Y Valency 2, element Y has high tendency of gaining electrons for its stability thus the compound formed will be B
elements X is positively charged while Y will be negatively charged
The groups or the families in the periodic table are denoted by the vertical column. Element in group 2 and 7 forms compound with ions X²⁺ and Y⁻. Thus, option B is correct.
What is the periodic group?A group of the periodic table is also called a family that has the elements placed togther with the same number of the valence electron. Group II has two valence electrons and VII has seven valence electrons in the outer shells.
The two valence electrons of the atom can be donated easily compared to acquiring the six electrons to complete the octet and stability. Similarly, the seven valence electrons are hard to donate but can accept one electron to achieve satbility.
The group II element X will donate its two electrons to acquire a +2 charge, whereas group VII element Y will accept one electron and acquire a -1 charge.
Therefore, option B. X²⁺ and Y⁻ presents the ions of the compound.
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Figure 5 shows how the temperature of a substance changed as it was heated. Which segment of the graph indicates that the substance was undergoing a change of state?
answer:
B
Why:
Because when heated up, the particles vibrate from the heat and keep on vibrating.
at point b of the diagram, the energy is gone to breaking bonds of the (let's assume) solid.
So there is no change in temperature.
I hope this helps please let me know if you need me to explain more.
When temperature is changing with respect to the time in the given graph, then substance B was undergoing a change of state.
What is change of state?When any substance converts from one form of matter to the other form, then this phenomenon is known as change of state.
In the given figure a graph represents the change in temperature of substances A, B, C and D with respect to the time. Temperature of the substances A, C & D keep continuous changing with respect to the time. But substance B shows change in state because it absorbs the heat to convert in another state by breaking old bonds and making new bonds and showing showing no change in temperature.
Hence, substance B was undergoing a change of state.
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Graphite conducts heat in a similar way to metals because it contains __________ __________. What two words complete the sentence?
Answer:
Free electrons
Explanation:
Graphite conducts heat in a similar way to metals because it contains free electrons.
Conductivity is arised from the delocalization of free electrons. Metals are electron rich and conduct thermally and electrically. Graphite conducts heat in a similar way because it contain delocalized electrons.
What is graphite?Graphite is an allotrope of carbon as diamond and fullerenes. Graphite exhibits a layered helical structures in which the carbon atoms are arranged in a hexagonal fashion.
Substances conduct electricity and heat when they are rich in electrons and are mobile to pass through it. Metals are electropositive and they contains extra electrons which can be delocalized between orbitals or energy levels.
This delocalization of electrons results in an a thermal or electrical current in the substance. Carbon is in sp2 hybridisation in graphite. Where, the electrons can transit from one layer to the other in the layered structure.
Therefore, the presence of delocalized electrons make graphite conducting.
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Can someone give me Two methods for monitoring and minimizing a human impact on the environment?
Copper 11 oxide and charcoal are black solids . How would you distinguish between the two solids
You have been given four substances that are all white
solids at room temperature. List three specific tests that
you could perform to figure out whether they are ionic or
molecular compounds.
Ionic compounds have a high melting point while molecular compounds have a low melting point.
If I have a white solid, this solid may be ionic or molecular. Ionic substances dissolve in water while molecular substances do not dissolve in water. This is the first test.
Secondly, an ionic solid has a high melting point while a molecular solid has a low melting point. Again, ionic substances are crystalline when felt while molecular compounds are non crystalline when felt.
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What do all the molecules in the table have in common?
Answer:
They all consist of the same amount of protons, electrons, and neutrons in an element.
Explanation:
For example in water (H20) contains 1 atom of protons, 1 atom of electrons and 1 atom of neutrons.
What’s solubility need it for science
Answer:
the ability of a compound to dissolve
Explanation:
salt dissolves in water so it would be soluble.
oil does not dissolve in water so it is not soluble
Why is knowledge of the activity series crucial in choosing which metal to build things with?
Answer:
activity series is a list of substances ranked in order of relative reactivity.
For example, magnesium metal can displace hydrogen ions from solution. So magnesium is more reactive than hydrogen:
Mg(s) + 2H⁺(aq) → H₂(g) + Mg²⁺(aq)
Zinc metal can also displace hydrogen ions from solution:
Zn(s) + 2H⁺(aq) → H₂(g) + Zn²⁺(aq)
so zinc is also more active than hydrogen.
But magnesium metal can displace zinc ions from solution:
Mg(s) + Zn²⁺(aq) → Zn(s) + Mg²⁺(aq)
so magnesium is more active than zinc.
The activity series including these elements would be Mg > Zn > H.
Chemists have built up a complete activity series in a similar way.
The most active metals are at the top of the table; the least active are at the bottom.
Any metal that is higher in the series will displace a metal that is below it in a
The knowledge of the activity series in choosing which metal to build things with because; it provides a basis for determining which metal ion is able to displace the other upon chemical interaction.
The choice of building material is a very important design consideration.
This is so because careful consideration must be taken while deciding which metal to build things with as the reactivity of metals vary.This variation is carefully quantified by the position of metals on the activity series.
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3. both covalent and ionic
EXPLANATION
Sodium Phosphate is an ionic compound formed by two ions, Sodium Na+ and Phosphate PO−3 . In order for these two polyatomic ions to bond the charges must be equal and opposite. Therefore, it will take three +1 sodium ions to balance the one -3 phosphate ion. However, polyatomic ions are held together by covalent bonds, so this compound contains both ionic and covalent bonds.
What is considered a pure substance?
Answer:
A substance that has a fixed chemical composition throughout is called a pure substance such as water, air, and nitrogen. A pure substance does not have to be of a single element or compound.
Explanation:
Compound: A substance that contains more than one element
pure substance: is made up of one substance made up of only one type of molecule
5 example of similarities between compression and tension stress?
Answer:
Mark me as Brainliest please
Explanation:
Compression vs Tension
Tension and compression are two concepts discussed in physics. Tension is a force, while compression is a phenomenon. Both these concepts play important parts in fields such as mechanical systems, automobile engineering, heat engines, material science, pendulums and various other fields. It is vital to have a proper understanding in tension and compression in order to excel in such fields. In this article, we are going to discuss what compression and tension are, their definitions, applications of compression and tension, the similarities between compression and tension and finally, the difference between compression and tension.
Copernicus believed the planetary motions were due to:
Answer:circular heliocentric orbits.
Explanation:
plesse hurry aand help with QQQQQ
Answer: the answer should be A the first one
plzz give me brainliest
determine whether each phrase describes starch, glycogen, or cellulose.
Answer:
Starch is a soft, white, tasteless powder that is insoluble in cold water, alcohol, or other solvents.
glycogen is a substance deposited in bodily tissues as a store of carbohydrates. It is a polysaccharide which forms glucose on hydrolysis.
Cellulose is a molecule, consisting of hundreds and sometimes even thousands of carbon, hydrogen and oxygen atoms.
A student compares a sample of isooctane with some petrol. the student found that the isooctane boiled at 99°C while the petrol boiled between 45 and 95°C. which of these is a puse Substance? Explain ur answer.
Answer:
The isooctane
Explanation:
A pure substance is, according to Wikipedia, "a chemical substance is a form of matter having constant chemical composition and characteristic properties." That's a lot of words, but we just need to focus on some of them: "constant... characteristic properties." The properties of a pure substance always stay the same, no matter what.
The boiling point of a substance is one of its properties. It looks like the petrol boils at different points, between 45 and 95°C. The isooctane, on the other hand, boils consistently at 99°C. So, we can infer that the isooctane is the pure substance.
Hopefully that was helpful! If you need more questions answered, let me know. :)
What is acid rainnnnnn
Answer:
ACID RAIN
Explanation:
duh
Put the sets of 3 elements in order from least metallic character to most metallic character. Help please!!
Answer:
29:Mn,V,Sr
30:Ni,Pd,Cs
31:Cr, Mo, W
32:Sn,Pb,Ti
33:F, P, As
Sorry I was in a rush so it may not be right; so check with this picture to help you out.
An atom's Lewis dot structure has three dots. Which of the following elements could it be, and why? (4 points)
Group of answer choices
Aluminum, because it is in group 13 and has three valence electrons.
Lithium, because it is a group 1 element with three total electrons.
Magnesium, because it is in period 3 and has three valence electrons.
Potassium, because it is an alkali metal and has three inner shell electrons.
Answer : The correct option is, Magnesium because it is a group 2 element with two valence electrons.
Explanation :
Element = Calcium
Atomic number = 20
Electronic configuration of Ca =
Number of valence electrons in Ca = 2
The number of inner shell electrons in Ca = 18
This option is wrong because lewis-dot structure shows only valence electrons not inner shell electrons.
Element = Carbon
Atomic number = 6
Electronic configuration of C =
Number of valence electrons in C = 4
This option is wrong because only outermost p-sublevel electrons are not showing in lewis-dot structure.
Element = Lithium
Atomic number = 3
Electronic configuration of Li =
Number of valence electrons in Li = 1
This option is wrong because it has only 1 electron in outermost shell.
Element = Magnesium
Atomic number = 12
Electronic configuration of Ma =
Number of valence electrons in Ma = 3
This option is correct.
Lewis-dot structure : It is defined as the structure in which valence electrons of the atom is shown as dots.
ANOTHER EXPLANATION:
Answer: C. Magnesium, because it is a group 2 element with two valence electrons.
An atom's Lewis dot structure has two dots. Which of the following elements could it be, and why?
A. Calcium, because it is an alkaline earth metal with two inner shell electrons.
B. Carbon, because it has two electrons in its outermost p sublevel.
C. Lithium, because it is a group 1 element with two bonding electrons.
D. Magnesium, because it is a group 2 element with two valence electrons.
Explanation:
If you were to look at the periodic table magnesium would be in group 2. Since magnesium is in group 2 therefore it will have two valence electrons. Calcium is another possible answer because it is also in group two, but for this quiz it is incorrect. Lithium is incorrect because it is in group 1 and therefore it would only have 1 valence electron. Carbon is also incorrect because it is in group 14 so it would have 4 valence electrons. Hope this helps and makes sense.
Good Luck!!
Have a great day Studying!
The Lewis dot structure of an atom has three dots. With three valence electrons and belonging to group 13, which of the following elements may it be?
Are the elements of group 13 metals?The semi-metal boron (B) and the metals aluminum (Al), gallium (Ga), indium (In), and thallium (In) are all members of the boron family (Tl). The periodic table's fifth element, boron (Z=5), is found in Group 13. It is categorized as a metalloid because of its characteristics, which combine those of metals and nonmetals.
What traits does group 13 exhibit?The Periodic Table of Elements places these elements in Group 13 (XIII) of the p block. Metallic elements include thallium, gallium, indium, and aluminum. In their outermost shells, they each have three electrons shell with the valence electron configuration ns2np1 (one electron in the p orbital and a complete s orbital).
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.
A chemist measured the temperature of a liquid to be 26 ∘C, then she heated the liquid to 83 ∘C. By how many Kelvins did the temperature change.
Answer: 57.C
Explanation: simple subtraction
24.) In humans animals and plants the DNA is found in the?
Answer:
chromosome
Explanation:
Answer:
Most of the DNA in all animals, humans, and plants is found in the cell nucleus. Humans, animals and plants contains both DNA and RNA in the cell nucleus and they have to be present in all because every organisms structure and function directly depends upon them.
Explanation:
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Answer:
Lithium has 1 valence electron, Sulfur has 6
A is oxidized, B is reduced
A is reducing agent, B is oxidizing agent
Explanation:
when an atom loses electrons, it is oxidized
when an atom gains electrons, it is reduced (almost think of when you add a negative number to a positive number, the positive number gets smaller or is reduced)
