Answer:
C. -66, 751 kjExplanation:
hope it helps
Which of the following is the best thermal insulator to reduce the transfer of
heat by convection?
A. Air
B. Water
C. Alcohol
D. A vacuum
Answer:
A
Explanation:
Arrange Cu, Ca, Na, Zn and Au on the basis of their decreasing reactivity.
Answer:
1. Sodium (Na) is the most reactive due to its lower number of shells which enables the protons in it's nucleus to attract more electrons.
2. Calcium (Ca) is next as it is a group 2 element and they can be quite reactive.
3. Zinc (Zn) is the third reactive as transition metals are not very reactive.
4. Copper (Cu) is less reactive than Zinc because it is closer to the center of the periodic table and therefore has more stability.
5. Gold (Au) is the least reactive.
What are the prefixes for molecular compounds?
Answer:
In nomenclature of simple molecular compounds, the more electropositive atom is written first and the more electronegative element is written last with an -ide suffix.
The Greek prefixes are used to dictate the number of a given element present in a molecular compound.
Prefixes can be shortened when the ending vowel of the prefix “conflicts” with a starting vowel in the compound.
Common exceptions exist for naming molecular compounds, where trivial or common names are used instead of systematic names, such as ammonia (NH3) instead of nitrogen trihydride or water (H2O) instead of dihydrogen monooxide.
Terms
nomenclatureA set of rules used for forming the names or terms in a particular field of arts or sciences.
electronegativeTending to attract electrons within a chemical bond.
electropositiveTending to not attract electrons (repel) within a chemical bond.
Chemical Nomenclature
The primary function of chemical nomenclature is to ensure that a spoken or written chemical name leaves no ambiguity concerning to what chemical compound the name refers. Each chemical name should refer to a single substance. Today, scientists often refer to chemicals by their common names: for example, water is not often called dihydrogen oxide. However, it is important to be able to recognize and name all chemicals in a standardized way. The most widely accepted format for nomenclature has been established by IUPAC.
Molecular compounds are made when two or more elements share electrons in a covalent bond to connect the elements. Typically, non-metals tend to share electrons, make covalent bonds, and thus, form molecular compounds.
Rules for Naming Molecular Compounds:
Remove the ending of the second element, and add “ide” just like in ionic compounds.
When naming molecular compounds prefixes are used to dictate the number of a given element present in the compound. ” mono-” indicates one, “di-” indicates two, “tri-” is three, “tetra-” is four, “penta-” is five, and “hexa-” is six, “hepta-” is seven, “octo-” is eight, “nona-” is nine, and “deca” is ten.
If there is only one of the first element, you can drop the prefix. For example, CO is carbon monoxide, not monocarbon monoxide.
If there are two vowels in a row that sound the same once the prefix is added (they “conflict”), the extra vowel on the end of the prefix is removed. For example, one oxygen would be monooxide, but instead it’s monoxide. The extra o is dropped.
Generally, the more electropositive atom is written first, followed by the more electronegative atom with an appropriate suffix. For example, H2O (water) can be called dihydrogen monoxide (though it’s not usually). Organic molecules (molecules made of C and H along with other elements) do not follow this rule.
Here are the prefixes in naming molecular compounds:
Mono- 1
Di- 2
Tri- 3
Tetra- 4
Penta- 5
Hexa- 6
Hepta- 7
Octa- 8
Nona- 9
Deca- 10
Molecular compounds are named using a systematic approach of prefixes to indicate the number of each element present in the compound.
I hope it helps ●~●
#CarryOnLearningThe work function of an element is the energy required to remove an electron from the surface of the solid. The work function for palladium is 503.7 kJ/mol (that is, it takes 503.7 kJ of energy to remove 1 mole of electrons from 1 mole of Pd atoms on the surface of Pd metal). What is the maximum wavelength of light that can remove an electron from an atom in palladium metal
Answer:
λ = 2.38 × 10^(-7) m
Explanation:
We are given the work function for palladium as 503.7 kJ/mol.
Now let's convert this to KJ/electron.
We know from avogadro's number that;
1 mole of electron = 6.022 × 10^(23) electrons
Thus,
503.7 kJ/mol = 503.7 × 1/(6.022 × 10^(23)) = 8.364 × 10^(-22) KJ/electron = 8.364 × 10^(-19) J/electron
Formula for energy of a photon is;
E = hv
Where;
h is Planck's constant = 6.626 × 10^(-34) J.s
v is velocity
Now, v = c/λ
Where;
c is speed of light = 3 × 10^(8) m/s
λ is wavelength of light.
Thus;
E = hc/λ
Making λ the subject, we have;
λ = hc/E
λ = (6.626 × 10^(-34) × 3 × 10^(8))/(8.364 × 10^(-19))
λ = 2.38 × 10^(-7) m
HELP ASAP Choose three sections of the electromagnetic spectrum. Rank them in order of energy. Give an example of how they are used for each.
Using the following samples below, elaborate on the practical uses of concave and convex
mirrors. Write your answer on a separate sheet of paper.
1. Car rear view mirror
2. Security
3. Street light reflectors
4. Shaving facial hair
5. Car light
Answer: Convex mirror is curved in the outward direction and concave mirror in the inward direction.
Explanation:
1. Car rear view mirror: It is a convex mirror which gives the indication of large field of view and it allows the driver to view the traffic behind the car.
2. Security: The reflective bulge surfaces of the convex mirrors reflect the light outwards and provides an expanded field of view of the entire view of shops and other places useful for security.
3. Street light reflectors: They use convex mirrors because they are able to spread the light over the wider area.
4. Shaving facial hair: Concave mirror is used in shaving facial hair. It gives a bigger view of face when it is at the position of pole and focal point of the mirror.
5. Car light: It uses concave mirror because of the converging power it can focus more light rays at a particular point.
Water is an amphoteric substance because it can receive and donate hydrogen ions.
- True
- False
Answer:
True
Explanation:
The answer is True...
Answer:
i think true
Explanation:
if right than tag me brilliant
Consider this equilibrium:
HCO3- + H2PO4-HPO42- + H2CO3.
What are the Brønsted-Lowry acids in this equilibrium?
A. HCO3- and H2CO3
B. HCO3 and HPO42-
C. H2PO4! and H2CO3
D. H2PO4' and HPO4-
E. HCO3 and H2PO4!-
Answer:
the answer is option E they are bronsted lowry acid
ionisation potential of the element increases across a period from left to right
Answer:
False
Explanation:
It actually decreases.
What is the cause of acid precipitation?
1) ozone
2) nitrogenous oxides
3) ammonia
4) chlorofluorocarbons (CFCs)
Answer:
nitrogenous oxides
Explanation:
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. ... In addition, the exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These pollutants cause acid rain.
The correct answer in you question is 2) nitrogenous oxide
I hope it helps ●~●
#CarryOnLearningWhich phrase best describes a Hawaiian eruption?
A. Slow-moving lava flows and explosions of pumice
B. Ash shooting high into the atmosphere
C. Fast-moving lava flows and explosions of cinder
D. Lava fountains and fissure eruptions
Answer:
C.faste-moving lava flows and explosion of cinder
Match the factors which affect the rate of dissolving/dissociation/diffusion.
1. increased surface area
2. like dissolves like
3. temperature
4. stirring spreads
rate proportional to kinetic energy
matching polarity
finely divided solute
solute throughout solution
Answer:
Increased surface area - finely divided solute
like dissolves like - matching polarity
temperature - rate proportional to kinetic energy
stirring spreads - solute throughout solution
Which of the following happens during an endothermic chemical change?
Heat is absorbed.
Heat is released.
Net energy decreases.
Net energy remains constant.
Answer:
Heat is absorbed.
Explanation:
Endothermic reactions: Heat is absorbed.
When there is a change in the endothermic chemical so here heat is absorbed.
What are Endothermic reactions?It is the type of the chemical reaction that absorbed the heat from the environment. The absorbed energy that gives the activation energy for the reaction to arise.
hence, When there is a change in the endothermic chemical so here heat is absorbed.
Therefore, the first option is correct.
Learn more about heat here: https://brainly.com/question/1488118
True or false, The atomic number of an element is a whole number that decreases as you read across each row of
the periodic table from left to right.
Answer:
I believe it's false because the atomic number is the number of protons in the nucleus of an atom.
If you refuse a legal chemical test issued by a law enforcement officer, the Division of Motor Vehicles is required to:
Answer: Revoke the driver's license for at least 12 months
Explanation:
Chemical tests are used in order to measure the amount of drugs or alcohol that is in the body of a person when the person was arrested. To do this, samples of the urine or blood of the person can be taken and the result will be used to know if the person was driving under the influence of alcohol or not.
If the person refuse a legal chemical test issued by a law enforcement officer, the Division of Motor Vehicles is required to revoke the the driver's license of the person for at least 12 months.
The general shape that an electron is located within an energy level_____
Answer:
valence
Explanation:
the level of energy electrons have within a general shape the energy level is valence.
What does physics study
Answer:
Physics is the branch of science that deals with the structure of matter and how the fundamental constituents of the universe interact. It studies objects ranging from the very small using quantum mechanics to the entire universe using general relativity.
Why are measurements important for science?
Give two reasons.
Please help meeee :(
Answer:
-Being in the service of quality, safety, designing and problem solving.
-It plays an importnat part in our lives too, to measure any surface, object, etc.
Explanation:
Measurement is perhaps one of the most fundamental concepts in science. Without the ability to measure, it would be difficult for scientists to conduct experiments or form theories.
Which of the following elements has three valence electrons? (2 points)
Li
C
Al
Mg
Answer:
Al
Explanation:
It has 3.
during the extraction of iron from iron oxide in the Blast Furnace state the function of limestone
Answer:
Redox reactions are involved in the extraction of metals from their ores, eg extracting iron by reduction within the blast furnace. Transition metals have high melting points and densities, form coloured compounds and act as catalysts
True or false, The atomic number of an element is a whole number that decreases as you read across each row of
the periodic table from left to right.
Two magnets are stuck together. What might you have to do to get them to separate?
Explanation:
The easiest method to separating magnets is to slide them apart. When separating magnets keep in mind shear force. Magnets are measured on pull strength, so are up to five times easier to move if they are pushed apart instead of pulled apart. Small magnets slide relatively easily, even without spacers.
Firmly slide them away from each other and far enough apart so that they don't hop back together. Neodymium magnets are quite strong.
What are properties of a magnet?The properties of the magnet are:
Magnets will attract ferromagnetic.Like poles of the magnet repel each other and unlike poles bait each otherThe poles of the magnet are in the team.Thus, slide them away from each other and far enough apart so that they don't hop back together.
To learn more about magnets click here:
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balance the following half equation. SO3^2- ➡️SO4^2-
Answer:
[tex]12H2O + 2(SO3)2 -> 3(SO4)2[/tex]
Explanation:
see below. This was balanced using the the aggregate redox species method, or ARS for short.
The balanced half equation of the given reaction can be written as:
[tex]SO_3^{2-} + H_2O \longrightarrow SO_4^{2-} +2H^+ +2e^-[/tex]
What is the balanced chemical equation?A chemical equation can be defined as the expression of a reaction in terms of chemical symbols of the elements. A chemical equation of the reaction involves reactants and formed products.
The chemical equation of the reaction in which the number of atoms of the elements is the same on both sides of the chemical equation is a balanced chemical equation.
According to the law of conservation of mass, the total mass of the elements on the reactant side and product side should be the same in a balanced equation.
Given the equation is SO₃²⁻ → SO₄²⁻
To balance the oxygen on both sides add water:
H₂O + SO₃²⁻ → SO₄²⁻
To balance the hydrogen on both sides add H⁺:
H₂O + SO₃²⁻ → SO₄²⁻ + 2H⁺
To balance the charges, add electrons:
H₂O + SO₃²⁻ → SO₄²⁻ + 2H⁺ + 2e⁻
Learn more about the balanced chemical equation, here:
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#SPJ2
A mixture of gases contains 0.320 mol CH4, 0.240 mol C2H6, and 0.300 mol C3H8. The total pressure is 1.45 atm. Calculate the partial pressures of the gases.
Answer:
pCH₄ = 0.540 atm
pC₂H₆ = 0.405 atm
pC₃H₈ = 0.505 atm
Explanation:
Step 1: Calculate the total number of gaseous moles
n = n(CH₄) + n(C₂H₆) + n(C₃H₈)
n = 0.320 mol + 0.240 mol + 0.300 mol = 0.860 mol
Step 2: Calculate the partial pressure of each gas
We will use the following expression.
pi = P × Χi
where,
pi: partial pressure of the gas "i"P: total pressureΧi: mole fraction of the gas "i"pCH₄ = 1.45 atm × 0.320 mol/0.860 mol = 0.540 atm
pC₂H₆ = 1.45 atm × 0.240 mol/0.860 mol = 0.405 atm
pC₃H₈ = 1.45 atm × 0.300 mol/0.860 mol = 0.505 atm
necesito que me ayuden a resolver lo de las imágenes por favor ... es urgente
Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0012 % Pb by mass. What volume of the water in milliliters contains 100 mg of Pb
Answer:
8.3 × 10³ mL
Explanation:
Step 1: Calculate the mass of water that contains 100 mg of Pb
The concentration of Pb in the sample is 0.0012% by mass, that is, there are 0.0012 g of Pb every 100 g of water. The mass of water that contains 100 mg (0.100 g) of Pb is:
0.100 g Pb × 100 g Water/0.0012 g Pb = 8.3 × 10³ g Water
Step 2: Calculate the volume corresponding to 8.3 × 10³ g of water
Since the solution is diluted, we will assume the density of the sample is equal than the density of water (1 g/mL).
8.3 × 10³ g × 1 mL/1 g = 8.3 × 10³ mL
The volume of the water in milliliters contains 100 mg of Pb is;
V = 8.3 × 10³ mL
Volume of SolutionWe are given the concentration of Pb in the sample as 0.0012% by mass.
That means that there are 0.0012 g of Pb in every 100 g of water.
Thus, the mass of water that contains 100 mg (0.100 g) of Pb is calculated as;
(0.100 g Pb × 100 g of Water)/0.0012 g of Pb = 8.3 × 10³ g of Water
Now, we know that the density of water (1 g/mL) but we are not given the density of the sample.
Thus, since the solution is diluted we can equally say that;
Density of sample = 1 g/mL
Formula for Volume is;
V = mass/density
Thus;
V = 8.3 × 10³ g/1 g/mL
V = 8.3 × 10³ mL
Read more about Volume of solution at; https://brainly.com/question/17055828
Consider the following reaction, where A and
E are hypothetical elements.
A + 3E --> AE3
The atomic mass of A is 42.1 amu.
The atomic mass of E is 56.2 amu.
If 42.6 g of A fully reacts, how many grams of
AE3 are expected to form?
Enter your numerical answer to 1 decimal
place. Do not include the units of "g".
Answer:
Enter your numerical answer to 1 decimal place. Do not include the units of "g". Question: Question 14 1 pts Consider the following reaction, where A and E are hypothetical elements. A+3E --> AE The atomic mass of A is 42.1 amu. The atomic mass of Eis 56.2 amu. If 42.6 g of A fully reacts, how many grams of AE, are expected to form?
What type of a liquid will have a pH value equal to 7? (1 point)
If I have 9.7 moles of gas at a pressure of 0.12 atm and at a temperature of 46°C, what is the volume of the
container that the gas is in?
Answer:
2117.02 litres
Explanation:
Using the ideal gas equation as follows;
PV = nRT
Where:
P = pressure of the gas (atm)
V = volume of the gas (L)
n = number of moles (mol)
R = gas law constant (Latm/molK)
T = temperature (K)
According to the information given in this question,
P = 0.12 atm
V = ?
n = 9.7moles
T = 46°C = 46 + 273 = 319K
R = 0.0821 Latm/molK
Using PV = nRT
0.12 × V = 9.7 × 0.0821 × 319
0.12V = 254.04
V = 254.04 ÷ 0.12
V = 2117.02 litres
Help me please I really need this tomorrow
19. place moth balls in the closet and observe after several days.
20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid
21. evaporation, condensation, precipitation
22. it produces new substances
23. vinegar Bubbles when baking soda is added
24. steam
