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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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
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
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 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.
What volume of 0.32M HCl is required to completely neutralize 50.0m mL of a 0.12M Mg(OH)2 solution?
Answer:
37.5 mL of HCl will be required for complete neutralization with magnesium hydroxide
Explanation:
[tex]{ \bf{2HCl _{(aq)} + Mg(OH)_{2(s)}→ MgCl_{2(s)} + 2H _{2} O_{(l)}}}[/tex]
we've to first get moles of magnesium hydroxide in 50.0 ml :
[tex]{ \sf{1 \: l \: of \: hydroxide \: contains \: 0.12 \: moles}} \\ { \sf{0.05 \: l \: of \: hydroxide \: contain \: (0.05 \times 0.12) \: moles}} \\ = { \underline{0.006 \: moles}}[/tex]
for complete neutralization:
[tex]{ \sf{1 \: moles \: of \: hydroxide\: react \: with \: 2 \: moles \: of \: acid}} \\ { \sf{0.006 \: moles \: react \: with \: \{0.006 \times 2 \}} \: moles} \\ = { \underline{0.012 \: moles \: of \: acid}}[/tex]
compare with acid molarity:
[tex]{ \sf{0.32 \: moles \: of \: acid \: occupy \: 1 \: litre}} \\ { \sf{0.012 \: moles \: of \: acid \: occupy \: ( \frac{0.012}{0.32}) \: litres }} \\ { \underline{ = 0.0375 \: litre \: \: = \: \: 37.5 \: ml}}[/tex]
What is the major organic product obtained from the reaction of ethylbenzene with nitronium ion, followed by benzylic oxidation?
a. 3-ethyl-aniline.
b. 4-nitro-benzoic acid.
c. 3-nitro-toluene.
d. 3-nitrobenzoic acid.
Answer:
b
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.
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:
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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Which compound is a carbohydrate. Nucleotide or protien or starch or amino acid
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 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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calculate the number of each atom in 2.5 gram of caco3
Answer:
[tex]2.5\; \rm g[/tex] of [tex]\rm CaCO_{3}[/tex] would contain:
Approximately [tex]1.5 \times 10^{22}[/tex] calcium atoms (approximately [tex]0.025\; \rm mol[/tex],)Approximately [tex]1.5 \times 10^{22}[/tex] carbon atoms (approximately [tex]0.025\; \rm mol[/tex],) andApproximately [tex]4.5 \times 10^{22}[/tex] oxygen atoms (approximately [tex]0.075\; \rm mol[/tex].)Explanation:
Look up the Avogadro constant: [tex]N_{\rm A} \approx 6.022 \times 10^{23}\; \rm mol^{-1}[/tex].
For example, "[tex]1\; \rm mol[/tex] of carbon atoms" would contain [tex]N_{\rm A}[/tex] carbon atoms (approximately [tex]6.022\times 10^{23}[/tex]) by definition.
Look up the relative atomic mass of carbon, calcium, and oxygen on a modern periodic table:
Calcium: [tex]40.078[/tex].Carbon: [tex]12.011[/tex].Oxygen: [tex]15.999[/tex].In other words, the mass of [tex]1\; \rm mol[/tex] of calcium atoms would be [tex]40.078\; \rm g[/tex]. The mass of [tex]1\; \rm mol\![/tex] of carbon atoms would be [tex]12.011\; \rm g[/tex], and the mass of [tex]1\; \rm mol \!\![/tex] of oxygen atoms would be [tex]15.999\; \rm g[/tex].
As the formula [tex]\rm CaCO_{3}[/tex] suggests, every formula unit of this ionic compound includes one calcium atom, one carbon atom, and three oxygen atoms. The formula mass of [tex]\rm CaCO_{3}\![/tex] would give the mass of every mole of [tex]\rm CaCO_{3}\!\![/tex] formula units.
Calculate the formula mass of [tex]\rm CaCO_{3}[/tex] from the relative atomic mass data:
[tex]\begin{aligned} & M({\rm CaCO_{3}}) \\ =\; & 40.078\; \rm g \cdot mol^{-1} \\ & + 12.011\; \rm g \cdot mol^{-1} \\ & + 3 \times (15.999\; \rm g \cdot mol^{-1}) \\ =\; & 100.086\; \rm g \cdot mol^{-1}\end{aligned}[/tex].
Calculate the number of [tex]\rm CaCO_{3}[/tex] formula units in that [tex]2.5\; \rm g[/tex] of this compound:
[tex]\begin{aligned}& n({\rm CaCO_{3}}) \\ =\; & \frac{m({\rm CaCO_{3}})}{M({\rm CaCO_{3}})} \\ =\; & \frac{2.5\; \rm g}{100.086\; \rm g \cdot mol^{-1}} \\ \approx\; & 0.025\; \rm mol\end{aligned}[/tex].
In other words, [tex]2.5\; \rm g[/tex] of [tex]\rm CaCO_{3}[/tex] would contain approximately [tex]0.025\; \rm mol[/tex] [tex]\rm CaCO_{3}\![/tex] formula units.
Again, there are one calcium atom, one carbon atom, and one oxygen atom in every [tex]\rm CaCO_{3}[/tex] formula unit. That approximately [tex]0.025\; \rm mol[/tex] [tex]\rm CaCO_{3}\![/tex] formula units would thus contain:
Approximately [tex]1 \times 0.025\; \rm mol = 0.025\; \rm mol[/tex] calcium atoms, Approximately [tex]1 \times 0.025\; \rm mol = 0.025\; \rm mol[/tex] carbon atoms, andApproximately [tex]3 \times 0.025\; \rm mol = 0.075\; \rm mol[/tex] oxygen atoms.Make use of the Avogadro constant to convert the numbers.
For example, the number of calcium atoms in that approximately [tex]0.025\; \rm mol[/tex] of calcium atoms would be:
[tex]\begin{aligned} & N({\text{calcium}) \\ = \; & n({\text{calcium}) \cdot N_{\rm A} \\ \approx \; & 0.025\; \rm mol \times 6.022\times 10^{23} \cdot mol^{-1} \\ \approx \; & 1.5 \times 10^{22} \end{aligned}[/tex].
Likewise, the number of carbon atoms in that approximately [tex]0.025\; \rm mol[/tex] of carbon atoms would be:
[tex]\begin{aligned} & N({\text{carbon}) \\ = \; & n({\text{carbon}) \cdot N_{\rm A} \\ \approx \; & 0.025\; \rm mol \times 6.022\times 10^{23} \cdot mol^{-1} \\ \approx \; & 1.5 \times 10^{22} \end{aligned}[/tex].
The number of oxygen atoms in that approximately [tex]0.075\; \rm mol[/tex] of oxygen atoms would be:
[tex]\begin{aligned} & N({\text{oxygen}) \\ = \; & n({\text{oxygen}) \cdot N_{\rm A} \\ \approx \; & 0.075\; \rm mol \times 6.022\times 10^{23} \cdot mol^{-1} \\ \approx \; & 4.5 \times 10^{22} \end{aligned}[/tex].
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
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 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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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
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
In rutherfords gold foil experiment, most alphas particles passed through the gold foil without deflection and were detected on the screen. What caused the particles to pass through without any deflection?
Answer:
The vast majority of the volume in an atom consists of the electron orbitals with electrons that have too little mass to deflect the alpha particles. So most pass right through the foil. Only the ones hitting the nucleus are deflected.
Explanation:
The whole reason Rutherford and his students conducted this experiment was to test the then current hypothesis that an atom consists of a homogeneous blend of atomic particles, known as the "plum pudding" model. If so, there should be no, or minimal, deflection of particles. That's not what they found. Since particles were found to be deflected, the group concluded that atoms must contain a large object, which became known as the nucleus.
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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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
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%).
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
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).
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
A 25.0 mL sample of 0.723 M HClO4 is titrated with a 0.273 M KOH solution. The H3O+ concentration after the addition of 66.2 mL of KOH is __________ M.
a. 0.723
b. 1.00 × 10-7
c. 2.81 × 10-13
d. 0.439
e. 0.273
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
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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.