Answer:
The percentage efficiency of the electrical element is approximately 82.186%
Explanation:
The given parameters are;
The thermal energy provided by the stove element, [tex]H_{supplied}[/tex] = 3.34 × 10³ J
The amount thermal energy gained by the kettle, [tex]H_{absorbed}[/tex] = 5.95 × 10² J
The percentage efficiency of the electrical element in heating the kettle of water, η%, is given as follows;
[tex]\eta \% = \dfrac{H_{supplied} - H_{absorbed} }{H_{supplied}} \times 100[/tex]
Therefore, we get;
[tex]\eta \% = \dfrac{3.34 \times 10^3 - 5.95 \times 10^2}{3.34 \times 10^3} \times 100 = \dfrac{549}{668} \times 100 \approx 82.186 \%[/tex]
The percentage efficiency of the electrical element, η% ≈ 82.186%.
Which 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
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.
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
ionisation potential of the element increases across a period from left to right
Answer:
False
Explanation:
It actually decreases.
What type of a liquid will have a pH value equal to 7? (1 point)
How many O2 molecules react with 47 CH4 molecules according to the preceding equation CH4 + O2 → CO2 + H2O
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.
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.
a) The bubbles must be negatively charged.
b) The bubbles must be positively charged.
c) The bubbles must have the opposite charge to the charge on the student.
d) The bubbles must have the same charge as the charge on the student.
Answer:
C
Explanation:
like charges repel each others so if they have the same charge they will move away from each other
how does liquid carbon dioxide connect to organic chemistry
please I need long answers
Explain the sharing of electrons between a water molecule that forms four hydrogen bonds with the other four water molecules
Answer:
The sharing of electrons between a water molecule that forms four hydrogen bonds with the other four water molecules:
Explanation:
The hydrogen bond is a weak electrostatic force of attraction that exists between a covalently bonded H-atom and a highly electronegative atom like N,O or F.
In the case of the water molecule,
the highly electronegative atom is Oxygen and the intermolecular hydrogen bond in water is as shown below:
Thus H-bond is a weak electrostatic attraction formed between H-atom and O-atom in water.
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.
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.
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In an electrically neutral atom, the number of
protons equals the number of neutrons.
protons equals the number of electrons.
neutrons equals the number of electrons.
A. Protons equals the number of neutrons
B. Protons equal the number of electrons
C. Neutrons equals the number of electrons
Answer: B
Answer:
B
Explanation:
because protons have a +1 charge and electrons have a -1 charge, so if an atom is neutral it must have the same amount of protons and neutrons
The reaction of an alkene and water in the presence of an acid catalyst to produce an alcohol is called ________.
Locations Cost of land Cost of equipment Cost of mining and reclamation Time taken to mine the area 1 $100,000 $10,000 $5,000 per day 30 days 2 $35,000 $6,000 $4,500 per day 45 days 3 $30,000 $7,500 $3,500 per day 120 days 4 $40,500 $8,000 $7,000 per day 65 days Considering all costs, which location will cost the least to the company to mine?
Answer:
Location 2 will cost the least to the company to mine.
Explanation:
a) Data and Calculations:
Locations Cost of land Cost of Cost of mining Time taken to
equipment and reclamation mine the area
1 $100,000 $10,000 $5,000 per day 30 days
2 $35,000 $6,000 $4,500 per day 45 days
3 $30,000 $7,500 $3,500 per day 120 days
4 $40,500 $8,000 $7,000 per day 65 days
Locations Cost of land Cost of Cost of mining Total
equipment and reclamation Costs
1 $100,000 $10,000 $150,000 ($5,000 * 30) $260,000
2 $35,000 $6,000 $202,500 ($4,500 * 45) $243,500
3 $30,000 $7,500 $420,000 ($3,500 * 120) $457,500
4 $40,500 $8,000 $445,000 ($7,000 * 65) $503,500
The 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
the representative particle for KBr is the?
Answer:
This is a chemical symbol for Potassium Bromide
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⁻
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Read the temperatures shown to the nearest 0.5°C.
I’ll mark you as brainlister
Answer:
The temperature to the nearest 0.5°C is 98.5°C
The reaction from NaOH and CH3COOH gives
a. Basic Salt
b. Acidic Salt
c. Normal Salt
d. Neutral Salt
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
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Una muestra de S2 (g) se coloca en un recipiente rígido vacío a 800 K y ésta ejerce una presión inicial de 0,92 atm, luego se combina para formar S8 (g) mediante la reacción: S2 (g) ⇆ S8 (g) Una vez alcanzado el equilibrio, la presión parcial de S2 (g) ha disminuido a 0,18 atm. Calcule Kp para la reacción a esta temperatura
Answer:g
Explanation:
What does binding energy measure?
A. The forces attracting electrons to a nucleus
B. The repelling forces pushing protons apart
C. The energy used to hold the nucleus together
D. The energy released in radioactive decay
Answer:
C. the energy used to hold the nucleus together
what do you mean by thick pile of volcanic materials??
Answer:
You should repent God is coming back soon
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.
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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 ●~●
#CarryOnLearningWater 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
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
Si 40 g de un compuesto C6H10O5 se disuelven en 500 g de agua, determine el punto de ebullición de esta solución. (Agua: temperatura de ebullición 100 °C y Ke = 0,52 °C/m)
The question is: If 40 g of a compound C6H10O5 are dissolved in 500 g of water, determine the boiling point of this solution. (Water: boiling temperature 100 ° C and Kb = 0.52 ° C / m).
Answer: The boiling point of given solution is [tex]100.256^{o}C[/tex].
Explanation:
Given: Mass of solute = 40 g
Mass of solvent = 500 g (1 g = 0.001 kg) = 0.5 kg
[tex]K_{b} = 0.52^{o}C/m[/tex]
Molality is the moles of solute present in kg of solvent.
Moles is the mass of substance divided by its molar mass. Hence, moles of [tex]C_{6}H_{10}O_{5}[/tex] (molar mass = 162.141 g/mol) is calculated as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{40 g}{162.141 g/mol}\\= 0.246 mol[/tex]
Now, molality of the solution is calculated as follows.
[tex]Molality = \frac{molesof solute}{mass(in kg)}\\= \frac{0.246}{0.5 kg}\\= 0.492 m[/tex]
The boiling point is calculated as follows.
[tex]\Delta T_{b} = K_{b}m[/tex]
where,
m = molality
Substitute the values into above formula as follows.
[tex]\Delta T_{b} = K_{b}m\\= 0.52^{o}C/m \times 0.492 m\\= 0.256^{o}C[/tex]
As the boiling point of water is 100 degree Celsius. So, the boiling point of solution is as follows.
[tex](100 + 0.256)^{o}C\\= 100.256^{o}C[/tex]
Thus, we can conclude that the boiling point of given solution is [tex]100.256^{o}C[/tex].
