Answer:
H
hydrogen have different properties
Which property altered during a chemical change is not altered during a physical change?
A. composition of the matter
B. temperature of the matter
C. volume of the matter
D. phase of the matter
The property altered during a chemical change that is not altered during a physical change is composition of the matter.
A physical change is one in which no new substance is formed and it is easily reversible.
A chemical change is one that is not easily reversible and no new substance is formed. It may be accompanied by absorption or evolution of heat.
The composition of a substance changes during a chemical change because bonds between atoms break and new bonds are formed. This does not occur during a physical change.
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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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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.
The density of gold is 19.3 g/cm3, and the density of iron pyrite is 5.02 g/cm3. What substance do you think you found?
Answer:
Step 1
1 of 2
V = m / D; V (nugget of gold) = 50 g / 5.0 g / cm 3 = 10 cm3; V (nugget of iron pyrite) = 50 g / 19 g / cm3 = 2.63 cm 3
Result
2 of 2
Due to these results you can conclude that nugget of gold which volume is 10 cm3 is bigger than volume of nugget of iron pyrite which is 2.63 cm3.
Explanation:
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 :)
How much heat is absorbed by a 112.5 g sample of water when it is heated from 12.5 °C to 92.1 °C? (Specific heat capacity of water is 4.184 J/g °C)
Answer:
[tex]\boxed {\boxed {\sf37,467.72 \ Joules }}[/tex]
Explanation:
We are asked to find how much heat a sample of water absorbed. Since we are given the mass, temperature, and specific heat, we will use the following formula.
[tex]q=mc \Delta T[/tex]
The mass (m) of the sample is 112.5 grams. The specific heat capacity of water (c) is 4.184 Joules per gram degree Celsius. The difference in temperature (ΔT) is found by subtracting the initial temperature from the final temperature.
ΔT= final temperature - initial temperatureThe water was heated from 12.5 degrees Celsius to 92.1 degrees Celsius.
ΔT= 92.1 °C - 12.5 °C= 79.6°CNow we know three variables and can substitute them into the formula,
m= 112.5 g c= 4.184 J/g °C ΔT= 79.6 °C[tex]q= (112.5 \ g )(4.184 \ J/g \textdegree C)(79.6 \textdegree C)[/tex]
Multiply the first 2 numbers. Note the units of grams cancel.
[tex]q= (112.5 \ g *4.184 \ J/g \textdegree C)(79.6 \textdegree C)[/tex]
[tex]q= (112.5 *4.184 \ J/ \textdegree C)(79.6 \textdegree C)[/tex]
[tex]q= (470.7 \ J/ \textdegree C)(79.6 \textdegree C)[/tex]
Multiply again. This time the units of degrees Celsius cancel.
[tex]q= (470.7 \ J/ \textdegree C *79.6 \textdegree C)[/tex]
[tex]q= (470.7 \ J *79.6 )[/tex]
[tex]q= 37467.72 \ J[/tex]
37, 467.72 Joules of heat are absorbed by the sample fo water.
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
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^_^
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%).
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
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)
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.
Based on properties of elements in the periodic table, which element is the best conductor of thermal energy?
(1 point)
argon (Ar)
O germanium (Ge)
O vanadium (V)
polonium (Po)
Answer:
Vanadium (V) is the best conductor of thermal energy in this list
Which compound is a carbohydrate. Nucleotide or protien or starch or amino acid
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
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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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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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
Oceanography does not include the study of which of the following topics?
A.the relationship between the Sun, Moon, and Earth
B.the relationship between the atmosphere, Earth, and the oceans
C.the Earth's oceans
D.the plants and animals that live in the oceans
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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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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How many inches are in 1.00 km
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.
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 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).
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:
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
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.
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.
Name the reaction type & mechanism of the following reactions:
Answer:
MECHANISM:
1) The lone pair on oxygen attacks the H-Br molecule forming a hydronium ion.
2) Formation of carbocation.
3) Attack of Nucleophile Br − .
Explanation:
Answer:
DISPLACEMENT REACTION
COMBINATION REACTION
DOUBLE DISPLACEMENT REACTION
DECOMPOSITION REACTION