Describe the two categories used to classify physical changes.
Answer:
Physical changes can be classified as reversible or irreversible. Melting is an example of a reversible physical change.
Explanation:
How many moles of iron are in 50.0g of iron? How many iron atoms are in 50.0g of iron?
Answer:
50g iron comprises 5.376 × 1023 atoms.
Explanation:
Define valence electrons.
Answer:
Electrons on the outermost shell of an atom. They are responsible for the chemical properties of an atom.
Which of the following shows a valid combustion reaction?
2Al + 2O2 → 2AlO + O2
C2H4 + 3O2 → 2CO2 + 2H2O
2CH4 + O2 → 2CO + 4H2
Ca + O2 → CaOH
Answer: C2H4 + 3O2 → 2CO2 + 2H2O
Explanation:
2Al + 2O2 → 2AlO + O2 Not Balanced Properly: 2Al + O2 = 2AlO
C2H4 + 3O2 → 2CO2 + 2H2O Looks Good
2CH4 + O2 → 2CO + 4H2 Not Correct: CO should be CO2
Ca + O2 → CaOH Not Balanced and No source for the H
Answer:
2H4+3O2 →2CO2+2H2
Explanation:
What is an example of a polar molecule
Question 8 options:
A molecule that is made of ionic bonds like NaCl.
A molecule that is made of covalent bonds like sugar.
A molecule made of covalent bonds that has partial positive and partial negative charges in different areas of the atom.
A molecule made of ionic bonds that has strong positive and strong negative charges in different areas of the molecule.
Answer:
The two main classes of molecules are polar molecules and nonpolar molecules. Some molecules are clearly polar or nonpolar, while others fall somewhere on the spectrum between two classes. Here's a look at what polar and nonpolar mean, how to predict whether a molecule will be one or the other, and examples of representative compounds.
Explanation:
so its c
An example of polar molecule is a molecule made of covalent bonds that has partial positive and partial negative charges in different areas of the atom.
What is covalent bond?
Covalent bond is defined as a type of bond which is formed by the mutual sharing of electrons to form electron pairs between the two atoms.These electron pairs are called as bonding pairs or shared pair of electrons.
Due to the sharing of valence electrons , the atoms are able to achieve a stable electronic configuration . Covalent bonding involves many types of interactions like σ bonding,π bonding ,metal-to-metal bonding ,etc.
Sigma bonds are the strongest covalent bonds while the pi bonds are weaker covalent bonds .Covalent bonds are affected by electronegativities of the atoms present in the molecules.Compounds having covalent bonds have lower melting points as compared to those with ionic bonds.
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How are traits inherited?
Please explain thoroughly
inherited traits are passed from parent to offspring according to the rules of Mendelian genetics. Most traits are not strictly determined by genes, but rather are influenced by both genes and environment
PLS HELP: Endocrine Organs Crossword
Valence electrons are electrons in the ? of an atom.
Answer:
Valence electrons are the outermost of electrons.
Explanation:
valence electrons are the outermost electrons of an atom located in the shell/ orbit
what is an environmental result from burning fossil fuels?
Answer:
The burning of fossil fuels contributes to the addition of greenhouse gases to the atmosphere. These gases trap thermal energy in the Earth's atmosphere.
In the reaction below the total mass of calcium in the reactants is 40. What is the total mass of calcium in the products?
Answer:
40
Explanation:
The total mass of calcium in the products is 40
What is the total mass number?The mass number (represented by the letter A) is defined as the total number of protons and neutrons in an atom. Consider the table below, which shows data from the first six elements of the periodic table. Consider the element helium. Its atomic number is 2, so it has two protons in its nucleus.
How do you find the mass number?Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.
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help me please the subject is siecnce
Answer:
okay your question in science
What is oxidation state?
Answer:
a number assigned to an element in chemical combination which represents the number of electrons lost (or gained, if the number is negative), by an atom of that element in the compound
Explanation:
sodium, magnesium, iron is zero.
The definition of oxidation state is as follows: Oxidation state is a number given to the atom of an element when participating in a chemical reaction.
OXIDATION STATE:The atoms of elements are not always neutral i.e. carry no charge. They sometimes carry either positive or negative charges to become ions. Ions can either be cations (positively charged) or anions (negatively charged). The amount of charges are represented by numbers placed as a superscript in front of the element involved. These superscript charge assigned to a corresponding element during a chemical reaction is called oxidation state. The oxidation state of an element portrays the number of electrons gained or lost during the reaction.Therefore, oxidation state can be defined as a number given to the atom of an element when participating in a chemical reaction.
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When pyridine is treated with a mixture of nitric and sulfuric acids, the major product is:.
Answer: 3-nitropyridine
Explanation:
I have to answer questions about science
Answer:
What Questions?
Explanation:
What Questions?
Answer:
Explanation:
What is the Questions frist ?
A disadvantage of disposing of waste polymers through _____ is that they must first be separated, which can be expensive. What is the missing word in this sentence?
A disadvantage of disposing of waste polymers through recycling is that
they must first be separated.
Recycling is the process of forming new polymers and compounds as against their disposal .
Recycling involves separating the items into various sections such as paper,
plastic , metal etc. This is because they both undergo different recycling
processes.
The disadvantage of this process is that it's time consuming and also
expensive as a great amount of time and man power is needed to
separate the waste items.
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help asap for brainlist
Answer:
Function A: +3
Function B: +2
y intercept is greater in Function B, the value is 16
Explanation:
The letter for element Q stands for "qualium." What would the compound in 1a be called?
(1 A)
Answer:
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what makes your pulse? Explain
bonding and kinetic energy quick check
1. The internal energy within a system associated with the motion of particles and that can be added to a substance is called (1 point)
o temperature
O kinetic energy
O thermal energy
O electrostatic forces
2. which statement describes the effect of adding more energy to a system, assuming a phase change does not occur?
0 the particles within the system will have greater motion and the temperature will increase
0 the particles within the system will have greater motion and the temperature will be grace
0 particles within the system will have less motion and the temperature will increase
0 the particles within the system will have less motion and the temperature will decrease
3. which statement correctly describes how a tractions that holds particles break
0 attractions occur due to gravitational forces when particles move fast enough these forces can no longer keep particles together
0 attractions due to Electrostatic forces when particles move fast enough these forces can no longer keep particles together
0 attractions due to electrostatic forces when particles have low enough energy these forces can no longer keep particles together
0 attractions occurred due to gravitational forces when particles have low enough energy these forces can no longer keep particles together
4. Which statement explains why a rubber band analogy is not a perfect comprehension for Bonds in a substance when considering phases change
0 for a phase change from solid to liquid the bonds do not break completely and particles can still slide past each other
0 for a phase change from liquid to gas the bonds do not break completely the particles can still slide past each other
0 for a phase change from liquid to gas the bonds break completely and of particles can independently of each other
0 phase change from solid to liquid the bond breaks completely particles can move independently of each other
5.the boiling point of benzene is 80°C. which pair of samples will have the same average kinetic energy of benzene molecules?
0 two samples of gaseous benzene, at 80°C and the other 90°C
0 two samples of liquid benzene, one at 70°C and the other at 80°
0 a sample of liquid benzene at 70°C and a sample of gaseous benzene at 90°C
0 a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°celectric
When energy is added to a system during phase change, the particles move faster.
When a substance is heated, the internal energy within a system associated with the motion of particles and that can be added to a substance is called thermal energy.
During a phase change, when more energy is added to the system, the particles within the system will have greater motion and the temperature will increase.
The attractions that hold molecules together are electrostatic forces. The correct statement about the attractions that hold particles is that attractions between particles break when attractions due to Electrostatic forces when particles move fast enough these forces can no longer keep particles together.
Rubber band is not a perfect comprehension for Bonds in a substance when considering phases change because for a phase change from liquid to gas the bonds do not break completely the particles can still slide past each other.
The pair of samples that will have the same average kinetic energy of benzene molecules is a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C.
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fork is a metal or nonmetal ?
The energy released by a nuclear fusion reaction is produced when
1. energy is converted to mass
2. mass is converted to energy
3. heat is converted to temperature
4. temperature is converted to heat
Answer:
2
Explanation:
energy produced in nuclear fusion or even fission is due to mass defect and it can be calculated by Einstein equation e=mc2
The statement, that describes energy released by a nuclear fusion reaction is produced is "mass is converted to energy."
What is nuclear fusion?Nuclear fusion is the process by which two light atomic nuclei merge to produce a single heavier one, releasing huge quantities of energy in the process.
A fusion reaction occurs when two light nuclei combine to form a single heavy nucleus. Because the overall mass of the resulting single nucleus is smaller than the mass of the two initial nuclei, the process releases energy.
That is, nuclear energy refers to the energy released as a result of mass loss during the nuclear fusion processes. Both of these processes transform mass loss into energy in accordance with Einstein's mass-energy ratio, E = [tex]mc^{2}[/tex]. As a result of the fusion reaction, mass is destroyed and energy is released.
Hence, the correct answer is 2.
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determine the ph of a buffer that is 0.55 M HNO2 and 0.75 M KNO2. tha value of Ka for HNO2 is 6.8*10^-4
Answer:
pH = 3.3
Explanation:
Buffer solutions minimize changes in pH when quantities of acid or base are added into the mix. The typical buffer composition is a weak electrolyte (wk acid or weak base) plus the salt of the weak electrolyte. On addition of acid or base to the buffer solution, the solution chemistry functions to remove the acid or base by reacting with the components of the buffer to shift the equilibrium of the weak electrolyte left or right to remove the excess hydronium ions or hydroxide ions is a way that results in very little change in pH of the system. One should note that buffer solutions do not prevent changes in pH but minimize changes in pH. If enough acid or base is added the buffer chemistry can be destroyed.
In this problem, the weak electrolyte is HNO₂(aq) and the salt is KNO₂(aq). In equation, the buffer solution is 0.55M HNO₂ ⇄ H⁺ + 0.75M KNO₂⁻ . The potassium ion is a spectator ion and does not enter into determination of the pH of the solution. The object is to determine the hydronium ion concentration (H⁺) and apply to the expression pH = -log[H⁺].
Solution using the I.C.E. table:
HNO₂ ⇄ H⁺ + KNO₂⁻
C(i) 0.55M 0M 0.75M
ΔC -x +x +x
C(eq) 0.55M - x x 0.75M + x b/c [HNO₂] / Ka > 100, the x can be
dropped giving ...
≅0.55M x ≅0.75M
Ka = [H⁺][NO₂⁻]/[HNO₂] => [H⁺] = Ka · [HNO₂]/[NO₂⁻]
=> [H⁺] = 6.80x010⁻⁴(0.55) / (0.75) = 4.99 x 10⁻⁴M
pH = -log[H⁺] = -log(4.99 x 10⁻⁴) -(-3.3) = 3.3
Solution using the Henderson-Hasselbalch Equation:
pH = pKa + log[Base]/[Acid] = -log(Ka) + log[Base]/[Acid]
= -log(6.8 x 10⁻⁴) + log[(0.75M)/(0.55M)]
= -(-3.17) + 0.14 = 3.17 + 0.14 = 3.31 ≅ 3.3
Which chemical equation represents a redox reaction?
TiCl4(s) + 2H2O(g) – TiO2(s) + 4HCl(g)
--
CaO(s) + SiO2(s) – CaSiO3)
Fe2O3(s) + 2Al(s) — Al2O3(s) + 2Fe()
+
CaCO3(s) — Cao(s) + CO2(g)
Answer:
CaCO3 yields CaO + CO2
Exclamation
Since the Decomposition state of a redox involves a broken down compound, this equation proves that this is a DECOMPOSITION since it is being broken down.
Please help This is for my chemistry class and I need to get it done but I’m lost and need answers
Answer:
chlorine is a non metal.
sodium is a alkali metal.
helium is a noble gas.
nickel is a transition metal
Complete combustion of 6.4g of compound K produced 8.8 g of carbon dioxide and 7.2 g of water. Calculate the empirical formula of K.
Chemical properties of water and oxygen for class 8
Is the gin world scary?
Answer:
Gin= Machine that picks cotton
Explanation:
This Machine was used in the early 1940s to help pick cotton to make things.
What is infrared energy? simplify it
Answer:
It is a type of radiant energy that's invisible to human eyes but that we can feel as heat.
8. Why are we focusing on high levels of ozone in the troposphere in this lab while in Lab 2 (Stratospheric Ozone) we focused on low concentrations of ozone in the stratosphere?
Answer:
f4
Explanation:
your welcome.
under which conditions do you expect helium gas to deviate most from ideal behavior?
Answer:
Explanation:
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[2] Supervisor
[2-1] Emergency Response
[2-2] Juggernaut
[2-3] Commander
[2-4] Division Director
