Which substance is an element that is composed of molecules?
A. water (H2O)
B. methane (CH4)
C. hydrogen (H2)
D. helium (He)
Answer:
the answer is hydrogen which is B
The substance is an element that is considerably composed of molecules known as hydrogen (H2). Thus, the correct option for this question is C.
What is a Chemical element?A chemical element may be defined as a species of an atom that remarkably bears a specific number of sub-atomic particles in its structure. These elements are not further decomposed into smaller components in a chemical reaction.
H2 is also known as molecular hydrogen. It forms when two hydrogen atoms are significantly bonded to one another in order to give rise to a molecule. Water is not an element, it is a molecule. While methane is a chemical compound that possesses a chemical formula CH4. Helium (He) is a chemical element only.
Therefore, hydrogen is an element that is composed of molecules. Thus, the correct option for this question is C.
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Axon diameters of cortico-cortical fibres in the human brain range from 0.16 um to 9 um in
length. Convert the length, 0.16 um, into meters using scientific notation. (Use the following
format: a x 10^b using the correct number of significant figures).
The conversion of units in science is achieved by the use of conversion factors.
A conversion factor is a number used to change a quantity from one unit to another.
The given unit here is the micrometer and we are expected to convert the quantity (mass in this case) from micrometer to meter.
The conversion factor to use is:
1 μm = [tex]1 * 10^-6 m[/tex]
Hence;
0.16 μm = 0.16 μm * 1 * 10^-6 m/ 1 μm
= 1.60 * 10^-7 m
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Which of the following is an example of quantization?
A. The distance the ball is passed
O B. The fans sitting in the bleachers
C. The coach pacing the floor
O-D. The movement of basketball players on a court
The correct option is D The movement of basketball players on a court.
What is basketball ?Basketball exists as a team sport in which two teams, most generally of five players each, opposing one another on a rectangular court, contest with the primary objective of shooting a basketball (approximately 9.4 inches (24 cm) in diameter) through the defender's hoop (a basket 18 inches (46 cm) in diameter mounted 10 feet (3.048 m) high to a backboard at each end of the court, while controlling the opposite team from shooting through their hoop. A field goal stands worth two points unless made from behind the three-point line when it stands worth three. After a foul, timed play stops and the player fouled or selected to shoot a technical foul is assigned one, two, or three one-point free throws. The team with the most points at the end of the game wins, but if regulation play passes with the score tied, an additional period of play (overtime) exists mandated.
Hence, The correct option is D The movement of basketball players on a court.
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In a year an adult cow produces around 3.571 x 10^27 molecules of methane CH4 a greenhouse gas how many moles of methane does this cow produce in a year
Answer:
[tex]\boxed{\boxed {\sf 5930.0 \ mol \ CH_4}}[/tex]
Explanation:
We are asked to find how many moles of methane (CH₄) a cow produces in a year. We must convert molecules of methane to moles of methane. We will do this using Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance.
In this case, the particles are molecules of methane. There are 6.022 × 10²³ molecules of methane in 1 mole.
We will convert molecules to moles using dimensional analysis. Set up a ratio using Avogadro's Number.
[tex]\frac {6.022 \times 10^{23} \ molecules \ CH_4}{ 1 \ mol \ CH_4}[/tex]
We are converting 3.571 × 10²⁷ molecules of methane to moles, so we multiply the ratio by this value.
[tex]3.571 \times 10^ {27} \ molecules \ CH_4 *\frac {6.022 \times 10^{23} \ molecules \ CH_4}{ 1 \ mol \ CH_4}[/tex]
Flip the ratio. It is still the same value, but the units of molecules of methane cancel.
[tex]3.571 \times 10^ {27} \ molecules \ CH_4 *\frac { 1 \ mol \ CH_4}{6.022 \times 10^{23} \ molecules \ CH_4}[/tex]
[tex]3.571 \times 10^ {27} *\frac { 1 \ mol \ CH_4}{6.022 \times 10^{23} }[/tex]
[tex]\frac {3.571 \times 10^ {27}}{6.022 \times 10^{23} } \ mol \ CH_4[/tex]
[tex]5929.923613 \ mol \ CH_4[/tex]
The original measurement of molecules of methane( 3.571 × 10²⁷ molecules) has 4 significant figures, so our answer must have the same. For the number we calculated, that is the ones place. The 9 in the tenth place tells us to round the 9 in the ones place up to a 0, then the 2 in the tens place up to a 3.
[tex]5930 \ mol \ CH_4[/tex]
We must add a placeholder zero in the tenth place to reach 4 sig figs.
[tex]5930.0 \ mol \ CH_4[/tex]
The adult cow produces approximately 5930.0 moles of methane in a year.
22. Which of the following is contained only in a eukaryotic cell? A. cell wall
B. nucleus
C. chromosomes
23.Which of the following terms represent the chemical reactions to break down food into simpler compounds in an organism?
A. anabolism
B. catabolism
C. nitrogen cycle
24.What types of molecules are bonded together to form a nucleotide? A. 2 nitrogen bases + 1 sugar
B. 2 sugars + 1 phosphate group
C. 1 nitrogen base + 1 phosphate group + 1 sugar
25.Glucose and oxygen are the two products of photosynthesis A. true
B. false
26.What is the first step in the refining of petroleum? A. cracking
B. drilling
C. distillation
27.When radium-226 (atomic number 88) decays by emitting an alpha particle, it becomes _________.
A. polonium-222 B. polonium-224 C. radon-222
28.The general name for hydrocarbons with at least one triple covalent bond is _________.
A. alkenes B. alkanes C. alkynes
29.What particle is emitted in alpha radiation? A. electron
B. photon
C. helium nucleus
30.Which type of compound is this? CH3CH2CH2CH2OH
A. alcohol B. aldehyde C. ether
31.Why are the molecules of hydrocarbons nonpolar? A. The intermolecular attractions are strong.
B. All the bonds are single covalent bonds.
C. The electron pair is shared almost equally in all the bonds.
32. An amino group and a carboxyl group are joined by a ___________ bond. A. peptide
B. protein
C. amino
33.What type of radiation is likely to occur when the ratio of protons to neutrons is below the band of stability?
A. alpha decay
B. beta decay
C. neutron emission
34.Covalent bonds are between bases in a DNA base-pair. A. true
B. false
35.What is the name of the functional group in the following compound? R—NH2
A. halogen B. amine C. ether
Answer:
22 options A cell wall
23 options A anabolism
24 options B 2sugar + 1phosphate group
4.25x10 ^ -3 in standered notation
Answer:
This Scientific notation;
[tex]4.25 \times {10}^{ - 3} [/tex]
This in standered notation ;
[tex]0.00425[/tex]
I hope I helped you^_^
If you know the atomic number of an element, what information does it give you about neutral atoms of that element?
Answer:
electrons
Explanation:
the atomic number tells you the number of Drotons in one atom of an element.It also tells you the number of electrons in a neutral atom of that element. The atomic number gives the "identity" of an element as well as its location on the periodic table.
What is the SI unit for energy? How is it abbreviated?
Answer:
Joule - J
Explanation:
As energy is defined via work, the SI unit of energy is the same as the unit of work – the joule (J).
Nobel gases (inert gases) have full set of valence electrons so they DO NOT REACT with other elements. Noble gases are elements.
A. stable
B. unstable
Answer:
Noble gases are stable as they have fully filled outermost orbital. Hence they do not participate in chemical reactions.
But Xenon reacts in some cases in favourable conditions
which atom can gain electrons lose electrons and how many ? if sodium is -2,8,1/and chlorine is -2,8,7
Answer:
A sodium atom can lose its outer electron. It will still have 11 positive protons but only 10 negative electrons. So, the overall charge is +1.
A major component of gasoline is octane . When octane is burned in air, it chemically reacts with oxygen gas to produce carbon dioxide and water . What mass of octane is consumed by the reaction of of oxygen gas
What's the difference between science and science methods?
Answer:
Science is related only to sense-experience, and reason based on the former. It is an accumulation of systematic and verifiable knowledge. The scientific method is one and the same in all branches of knowledge. The unity of science, according to him, consists in its method, not in its material alone.
Explanation:
Al(s) + NaOH(aq) → Al(OH)3(s) + Na+(aq) displacement, or decomposition.
Answer:
Displacement
Explanation:
OH- in the reactant side of the reaction has switched from Na+ to Al 3+ in the product side. Decomposition is where a compound from the reactant side of the reaction would dissolve into elements in the product side, but that's not the case in this example.
If an inverse relationship exist between x and y, and k = 200, which of the following would be points on the graph?
-(200,0.1)
-(100, 0.2)
-(400, 0.5)
-(800, 0.4)
Answer:
The answer is (400, 0.5)
Which of the following atoms is expected to have two unpaired electrons?
Al
Mg
Na
None of the above
Answer:
none of the above answers
A bike lost 20% of its value after the first year, its value after the first year is $1039. Calculate the original price of the bike?
Answer:
$1246.90
Explanation:
Since the bike lost [tex]20%[/tex]% of it's value and it now currently at $[tex]$1039[/tex], we have to do 20% * $1039 to find the amount of money lost. 20%*1039=207.8. We have to add it up to find the original value so 1039+207.8=$1246.8
what is the formula of water
Answer:
H2O is the formula of water
Answer:
H²O is formula of water
Explanation:
2 molecule of hydrogen and 1 molecule of oxygen
Which option describes the molecule geometry of a molecule with one bond and three lone pairs?
A. octahedral
B. linear
C. angled
D. tetrahedral
The option describes the molecule geometry of a molecule with one bond and three lone pairs. Thus, option B is correct.
What is covalent bond?A covalent bond is defined as a chemical bond that includes the sharing of electron pair between atoms.The pair of electrons are know as bonding pairs and the stable balance of attractive and repulsive forces between atoms.
The properties of covalent bond are mentioned below:
The covalent compounds have low melting points and boiling points.The covalent compounds do not contain electricity.
The covalent compounds are having lower enthalpies of vaporization and fusion.The covalent compounds are easily catches fire and are more flammable than ionic compounds.
The covalent compounds are very soft and flexible. The physical properties of covalent compounds are that they have lower melting points and electrical conductivity.
Therefore, The option describes the molecule geometry of a molecule with one bond and three lone pairs. Thus, option B is correct.
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Choose the correct definition of PRESSURE.
1. force per unit area
2. the rate of work done
3. a push or a pull applied on an object
4. product of force with displacement of object
Pressure - Force per unit area
Hope it helped :)
A carboxylic acid is an organic acid based on the carboxylate functional group, −COO−−COO−. The pKa of acetic acid, CH3COOHCH3COOH, is 4.80. The pKa of chloroacetic acid, CH2ClCOOHCH2ClCOOH, is 2.99. The pKa of trichloroacetic acid, CCl3COOHCCl3COOH, is 0.79 Acetic acid diluted in water is known as vinegar, which is safe for many food, cleaning, and alternative health applications. The other two acids are quite hazardous to our health in addition to being stronger acids, and their reactivity makes them useful as reagents in organic synthesis. Let us consider what accounts for the increased acidity and how to test those hypotheses.
Consider what trend exists in the pKapKa values for these three carboxylic acids based on their molecular formulas, then complete the following statement regarding a trend that relates to this phenomenon.
The pKa values of the carboxylic acids tend to decrease as the ___ increases.
the electronic configuration of an atom of element X is 2,8,2 what will be the valency of the element x
The element is Magnesium
It has total 12 electronsit has electronic configuration
[tex]\\ \sf\longmapsto 2,8,2[/tex]
or
[tex]\\ \sf\longmapsto 1s^22s^22p^63s^2[/tex]
In valence cell it has 2 electrons and therefore its valency is 2
You are unable to lift an object. Which property makes the object difficult to lift?(1 point)
mass
density
weight
volume
Answer:
You are unable to lift an object. Which property makes the object difficult to lift?(1 point)
weight
How many inches are in 1.00 km
Which of the following is a feature of a Type IV flotation device?
Answer:
A Type IV PFD is an approved device designed to be thrown to a person in the water. It is not designed to be worn. It is designed to have at least 16.5 pounds of buoyancy. The most com- mon Type IV PFD is a buoyant cushion.
Explain why there was a reaction between zinc metal and a salt solution of copper sulphate please help me
Answer:
When zinc is added to copper sulphate (CUSO4) solution due to more reactivity of zinc, cooper is replaced by the zinc and forms zinc sulphate. During the process, the colour of the solution changes from blue to colourless.
Which isotope of iron from the periodic table is most abundant
Answer:
Iron has four naturally-occurring stable isotopes, 54Fe, 56Fe, 57Fe and 58Fe. The relative abundances of the Fe isotopes in nature are approximately 54Fe (5.8%), 56Fe (91.7%), 57Fe (2.2%) and 58Fe (0.3%).
Which property is an intensive, rather than an extensive, property of matter?
A. volume
B. density
C. mass
D. length
Answer:
Density other dude is incorrect
Explanation:
Density is an intensive, rather than an extensive property of matter.
WHAT ARE INTENSIVE AND EXTENSIVE PROPERTIES?
The property of matter is divided into two categories namely: intensive and extensive properties.Intensive properties are those properties that are not dependent on the size or amount of the substance. Examples include density, temperature, boiling point, melting point etc. Extensive properties are those properties that depend on the size or amount of the substance involved. Examples are length, mass, volume weight etc.Therefore, density is an intensive, rather than an extensive property of matter.
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Given the ion Al+3, what species would you expect to form with each of the following ions? OH- ___________ S2- ___________ PO43- _________
Ionic substances are formed by exchange of valencies between the ions that make up the substance.
The ion [tex]Al^3+[/tex] has a valency of +3. It exchanges this valency with other ions as it forms ionic substances.
In the case of OH- which has a valency of 1, the compound Al(OH)3 is formed.
In the case of [tex]S^2-[/tex] which has a valency of 2, the compound Al2S3 is formed.
In the case of [tex]PO4^3-[/tex] which has a valency of 3, the compound AlPO4 is formed.
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balanced equation for the decomposition by heating of iron(II) sulfate heptahydrate
The balanced equation for the decomposition by heating of iron(II) sulfate heptahydrate is FeSO₄.7H₂O —> FeSO₄ + 7H₂O.
What is a balanced equation?An equation for a chemical reaction is said to be balanced if both the reactants and the products have the same number of atoms and the total charge for each component of the reaction. In other words, both sides of the reaction have an equal balance of mass and charge.
Here, in the equation FeSO₄.7H₂O —> FeSO₄ + 7H₂O
There is one molecule of iron is given on both sides and seven molecules of water given on both sides. So this equation is balanced. When there are similar molecules present on both sides. If the count on both sides is equal then this is called a balanced equation.
Thus, the balanced equation is FeSO₄.7H₂O —> FeSO₄ + 7H₂O.
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which is the best interpretation of the two flat portions of the graph
A. These show where kinetic energy is increased
B. These show where temperature is at 0 Celsius
C. These show where thermal energy does not exist
D. These show were changes of state are occurring
Answer:
b
Explanation: