Answer:
Si > Al > Mg > Na
Explanation:
In an atom, there is the positively charged particle' the proton, the negatively charged particle; the electron and neutral charged particle; the neutron. The effect of the proton on an atom that is the ability of these positive particles to attract the negative[valence electrons] particles is known as Effective nuclear charge.
[1]. Electron configuration of Silicon, Si = (1s²2s²2p⁶) 3s²3p².
The configuration part of Si in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.
The total number of electrons = 14, the inner electrons= 10. Thus, effective nuclear charge = 14 - 10 = 4.
[2]. Electron configuration of Aluminum, Al = (1s²2s²2p⁶) 3s²3p¹.
The configuration part of Al in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.
The total number of electrons = 13, the inner electrons= 10. Thus, effective nuclear charge = 13 - 10 = 3.
[3]. Electron configuration of Magnesium, Mg = (1s²2s²2p⁶) 3s²
The configuration part of Mg in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.
The total number of electrons = 12, the inner electrons= 10. Thus, effective nuclear charge = 12 - 10 = 2.
[4]. Electron configuration of sodium, Na = (1s²2s²2p⁶) 3s¹.
The configuration part of Na in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.
The total number of electrons = 11, the inner electrons= 10. Thus, effective nuclear charge = 11 - 10 = 1.
An electric circuit has an expected current of 80 amps. An electrician measures the current in the circuit at 120 amps Which statement provides a possible explanation for this observation?
There is not enough electrical energy in the circuit.
The circuit has an extra resistor
There is not enough voltage in the circuit.
A resistor in the circuit is broken
If an electric circuit has an expected current of 80 amps. An electrician measures the current in the circuit at 120 amps, the statement that provides a possible explanation for this observation is that there is not enough voltage in the circuit.
The third option is correct.
What is an electrical circuit?An electrical circuit is described as a network consisting of a closed loop, giving a return path for the current.
It is a known fact that the electrical energy in any circuit is given by the product of the current and voltage and if the current is higher than expected it means that the voltage is not enough to keep the current at the expected level.
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Answer: d
Explanation: i took the test
Which conclusion was a direct result of the gold foil experiment?
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. Therefore, each atom in the foil was composed mostly of empty space because most alpha particles directed at the foil.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.
Each atom in the foil was composed mostly of empty space because most alpha particles directed at the foil. This conclusion was the direct result of the gold foil experiment.
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The weight loss of an aluminum alloy corroding in a solution of hydrochloric acid was observed to be 0.250 g/cm2 after an 8 h immersion period [13]. What is the corresponding anodic current density in milliamperes per square centimeter, assuming that all the corrosion is due to the following anodic half-cell reaction:
This question is incomplete, the complete question is;
The weight loss of an aluminum alloy corroding in a solution of hydrochloric acid was observed to be 0.250 g/cm² after an 8 h immersion period [13]. What is the corresponding anodic current density in milliamperes per square centimeter, assuming that all the corrosion is due to the following anodic half-cell reaction:
Al → Al³⁺ + 3e⁻
The atomic weight is 58.7 g/mol
Answer:
Current density in milliamperes per square centimeter is 45.81 mA/cm²
Explanation:
Given the data in the question;
we know that Faradays law of electrolysis states that;
amount of substance produced at each electrode is directly proportional to the quantity of charge flowing through the cell.
so
m = ( Q/F) (M/z)
where m is the mass of substance liberated at an electrode( 0.250 g/cm²)
Q is the total electric charge passed through the substance
F is Faradays constant (96,500 C/mol)
M is the molar mass of the substance( 58.7 g/mol ) and Z is the number of electrons transferred(3)
Also
we know that; Q = It
where I is current and t is time( 8hrs × 60 × 60 = 28800 sec )
we substitute Q = It into our equation'
we have;
m = ( It/F) (M/z)
m = ItM / Fz
mFz = ItM
I = mFz / tM
so we substitute
I = [0.250 g/cm² × 96,500 C/mol × 3] / [ 28800 × 58.7 g/mol]
I = 72375 / 1690560
I = 0.04581 A/cm²
we know that; 1 ampere = 1000 milliampere
so
I = 0.04581 × 1000
I = 45.81 mA/cm²
Therefore, current density in milliamperes per square centimeter is 45.81 mA/cm²
Pls help, science 8th grade question, #11 thx :)
Read the descriptions below of two substances and an experiment on each. Decide whether the result of the experiment tells you the substance is a pure substance or a mixture, if you can.
Sample A is of a coarse grey powder with a faint unpleasant smell. of the powder is put into a funnel lined with a sheet of thick paper. Distilled water is poured slowly over the powder. Most of the powder disappears, but of a gritty black sand-like material is left on the surface of the paper. Pouring more water over the black material doesn't change how much of it there is.
Sample B is a solid yellow cube with a total mass of 50.0 g. The cube is put into a beaker filled with 250. mL of water. The cube collapses into a small pile of orange powder at the bottom of the beaker. When this powder is filtered out, dried and weighed, it has a total mass of 29.9 g. If the experiment is repeated with 500. mL of water, the powder that's left over has a mass of 10.0 g.
Answer:
Sample A - mixture
Sample B- Mixture
Explanation:
Looking at sample A, we can see that as water was poured over sample A, the sample was separated into its components as the powder disappeared leaving behind a gritty black sand-like material on the surface of the paper. A separation of the mixture has taken place.
In sample B, we can clearly see that it is a mixture because the amount of solid recovered is much less than the total mass of the solid put into the beaker. The sample must have been separated into its components.
A chemist determines by measurements that .060 moles of nitrogen gas participate in a chemical reaction. Calculate the mass of nitrogen gas that participates. Be sure your answer has the correct number of significant digits.
Answer:
1.7 g N₂
Explanation:
In order to convert moles of nitrogen gas (N₂) to grams, we'll use its molar mass:
Molar mass of N₂ = (Atomic Mass of N)*2 = (14.00 g/mol)*2 = 28.00 g/mol0.060 mol N₂ * 28.00 g/mol = 1.68 g N₂0.060 only has two significant digits, so the reported answer should have two significant digits as well. Meaning the answer is 1.7 g.
four difference between electrolytic cell and electrochemical cell
Answer:
Electrochemical cells convert chemical energy into electrical energy or vice versa. Electrolytic cell is a type of electrochemical cell in which electrical energy is converted into chemical energy. ... Electrolytic cells consist of positively charged anode and a negatively charged cathode.
I hope it's help
atomic radius(size)______ from left to right across a period on the periodic table
Answer:
Decreases
Explanation:
Under what conditions would wind blow weakly or very little?
50 Points and Brainliest for right answer
Answer:
A gentle wind or when the wind blows slowly, it is called a breeze.
Explanation:
Breezes are the result of differences in air temperature. Warm air rises, leaving behind low pressure near the ground. Cold air creates high pressure and sinks to compensate; wind then blows from areas of high pressure to areas of low pressure to try to equalize pressures.
Answer:
under low pressure of air makes wind blow weakly or very little.
What type of charge do ionic compounds have
Answer:neutral
Explanation:ionic compounds is between a cation and anion so they cancel eachother out
You are working in the lab and spill some acid on the counter. Because you don't want to get into trouble, you decide to clean it up by yourself. What would be best to reduce the acidity of the spill?
Answer:
By adding baking soda
Explanation:
The best way to reduce the acidity of the spill would be to add some amount of baking soda to the spill and then clean it up with a towel or any other appropriate item.
Baking soda is made up of sodium bicarbonate and has the capacity to react with acid to produce a salt and carbonic acid. The carbonic acid readily decomposes to produce carbon dioxide and water. For example, sodium bicarbonate reacts with hydrochloric acid according to the equation below:
[tex]NaHCO_3 + HCl --> NaCl + H_2CO3[/tex]
[tex]H_2CO_3 --> H_2O + CO_2[/tex]
One would expect the addition of a base to the spilled acid to work in a way as to neutralize the acid but bases are also corrosive and only a stoichiometrically balanced quantity would completely neutralize the acid. Thus, the quantity might not easily be determinable and one can end up doing more harm than good.
Hence, the best option is to add baking soda to the spilled acid to reduce its acidity before cleaning it off.
PLEASE HELP!! PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP
CHEMJSTRY!! LONE PAIRS WILL GIVE BRAINLIEST IF CORRECT!
Answer:
T
Explanation:
Which chemical equation is unbalanced?
A). C+O,, CO,
B). Sr t+ O2 2SFO
C). 6H, + 30, 6H,O
D). H, +H, +O,-→ H,0 + H,O
Answer:
The options in this question are unclear, the clear options are as follows:
A. C + O2 → CO2
B. Sr + O2 → 2SrO
C. 6H2 + 3O2 → 6H2O
D. H2 + H2 + O2 → H2O + H2O
The answer is B
Explanation:
A balanced chemical equation is that equation in which atoms of each elements in the reaction are of equal number on both sides of the equation (product and reactant). To balance a chemical equation, coefficients are used.
In this question, four chemical equations are given as follows:
- C + O2 → CO2
In this equation, atoms of carbon (1) and oxygen (2) are the same on both sides, hence, it is BALANCED.
- Sr + O2 → 2SrO
In this equation, Sr has 1 atom on the reactant side but 2 atoms on the product side. Hence, it is UNBALANCED. The balanced equation will be: 2Sr + O2 → 2SrO
- 6H2 + 3O2 → 6H2O
In this equation, atoms of hydrogen (12) and oxygen (6) are the same on both sides, hence, it is BALANCED.
- H2 + H2 + O2 → H2O + H2O
In this equation, atoms of hydrogen (4) and oxygen (2) are the same on both sides, hence, it is BALANCED.
What are three different ways an animal uses energy from its food
Answer:
Animals obtain energy from the food they consume , using that energy to maintain body temperature and perform other metabolic functions. Glucose, found in the food animals eat ,is broken down during the process of cellular respiration into energy source called ATP.
When 3.00 moles of hydrogen molecules and 1.50 moles of oxygen molecules react, they form 3.00 moles of water
When 3.00 moles of hydrogen molecules and 1.50 moles of oxygen molecules react, they form 3.00 moles of water
according to the reaction below.
2H2+ O2 + 2H2O
How many grams of oxygen were required?
2H, + O2 + 2H2O
How many grams of oxygen were required?
Mass of Oxygen required : 24 grams
Further explanationGiven
3 moles of H
1.5 moles of O
3 moles of H₂O
Required
Mass of O
Solution
Reaction
2H₂ + O₂ ⇒ 2H₂O
Mass of Oxygen for 1.5 moles of O :
= mol x Ar O
= 1.5 moles x 16 g/mol
= 24 grams
23. How many different elements are in the compound sodium carbonate (Na2CO3)? *
a. 1
b. 3
C. 6
d.7
Na, C, and O so the answer is c. 3
PLEASE HELP ASAP I NEED IT HELP PEASEEEEEEEEEEE it’s number 4 (this is science)
Determine the mass of oxygen that is needed to react with 33 grams of phosphorus.
4P + 5 O2 → 2 P205
A
27.3 grams O2
B
1.33 grams O2
С
213 grams 02
D
42.6 grams 02
Answer:
D = 42.6 g
Explanation:
Given data:
Mass of oxygen needed = ?
Mass of phosphorus react = 33 g
Solution:
Chemical equation:
4P + 5O₂ → 2P₂O₅
Number of moles of phosphorus:
Number of moles = mass/molar mass
Number of moles = 33 g/ 30.97 g/mol
Number of moles = 1.065 mol
now we will compare the moles of P and oxygen.
P : O₂
4 : 5
1.065 : 5/4×1.065 = 1.33mol
Mass of oxygen needed:
Mass = number of moles × molar mass
Mass = 1.33 mol × 32 g/mol
Mass = 42.6 g
PLEASE HELPPP!!!!!!!
Scientists observe patterns in matter. They organize matter into groups based on shared physical and chemical properties. Which statement describes a chemical property that many elements might share?
A. bonds easily with oxygen in the air
B. boils between 90°C and 100°C
C. shines when polished
D. floats in water
Answer:
a
Explanation:
bonding is chemical
A chemicals change includes bond making or breaking. The reaction between two atoms or molecules is their chemical property. Thus bonding with oxygen in air is a common chemical property of elements.
What is chemical change?A change in which a substance undergo chemical bond making or breaking and forming new products. Whereas, a physical change does not involve these bond breaking or formation instead a phase change occurs there. Such as conversion of solids to liquids.
All the elements in the periodic table have their characteristic chemical and physical properties. Metallic shining is a physical property of metallic elements and floats in water describes the density of that element which is a physical property.
Similarly, boiling and melting are physical properties and they do not include any bond formation or breaking of the element.
The reaction with oxygen in air called oxidation forming their oxidised product is a chemical change. Thus, option A is correct.
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Which factor can help balance Earth’s temperature?
Answer:
Clouds
Explanation:
Because I just got it right
The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A compound exhibits intense absorption at 1715 cm-1 but none above 3000 or in the 1000-1350 cm-1 range.
Relative absorption intensity: (s)=strong, (m)=medium, (w)=weak.
What functional class(es) does the compound belong to?
List only classes for which evidence is given here. Attach no significance to evidence not cited explicitly.
a. alkane (List only if no other functional class applies.)
b. alkene h. amine
c. terminal alkyne i. aldehyde or ketone
d. internal alkyne j. carboxylic acid
e. arene k. ester
f. alcohol l. nitrile
g. ether
Answer:
B.
Explanation:
Functional group can be interconverted into each ther by the means of suitable reagent. Functional group are responsible for the chemical and physical properties of a compound. The given spectral data represents alkene.
What is functional group?A group of atoms forming a component of a molecule that accounts for a particular function or chemical behavior is called a functional group. There are so many functional group in organic chemistry.
The list of functional group are as follow:
Carboxylic group COOH
Alcoholic group OH
Ammine group NH₂
Alkene -c=c-
Ketonic group R-CO_R
Aldehydic group R-CHO
Thiol group R-S-H
Cyanide group -CN
Functional group can be detected by using spectral data. The given spectral data represents alkene.
Therefore the correct option is option B.
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Do the substances that are reactants in a chemical reaction remain the same after the reaction is complete?
Explain how the valence electrons are related to the element's period.
Answer:
The number of valence electrons in an atom is reflected by its position in the periodic table of the elements (see the periodic table in the Figure below). Across each row, or period, of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next
Calculate the concentration of hydrogen ions in a healthy person’s blood that has a pH of 6.40.
Answer:
[H⁺] = 3.98×10⁻⁷ M
Explanation:
Given data:
pH of blood = 6.40
Hydrogen ion concentration = ?
Solution:
Formula:
pH = - log[H⁺]
by rearranging this formula,
[H⁺] = 10⁻(pH) or [H⁺] = antilog (-pH)
By putting values,
[H⁺] = 10 ⁻⁶°⁴⁰
[H⁺] = 3.98×10⁻⁷ M
In a chemical reaction, where is the catalyst located
A. on the reactant side
B. on the product side
C. above the arrow
D. on both sides of the arrow
Answer:
A. on the reactant side
Explanation:
A catalyst will appear in the steps of a reaction mechanism, but it will not appear in the overall chemical reaction
How many grams are presented in a 7.4 moles sample of H2O?
Answer:
130g
Explanation:
For every mole of a substance, there is a molar mass that coincides with the masses on the periodic table. For one mole of H2O, you would add the molar masses of the two hydrogen atoms and the oxygen atom to get 18.016g. You would then take this molar mass and multiple it by the amount of moles present (7.4) to get 133.3184g
From here, you would round to the significant figures to get 130g
In sediments and waterlogged soil, dissolved O2 concentrations are so low that the microorganisms living there must rely on other sources of oxygen for respiration. Some bacteria can extract the oxygen in sulfate ions, reducing the sulfur in them to hydrogen sulfide gas and giving the sediments or soil a distinctive rotten-egg odor.
Required:
a. What is the oxidation number of sulfur in these compounds?
b. Write the net ionic equation for the reaction under acidic conditions (H3O+) that releases O2 from sulfate and forms hydrogen sulfide gas. Use water as the reactant In the hall-reaction that describes the formation of oxygen.
Answer:
1) SO₄ ²⁻ : (+6)
H₂S : (-2)
Explanation:
a) Sulfate reducers are widespread in muds and other sediments, water-logged soils, etc., environments that contain SO₄ ²⁻ and become anoxic as a result of microbial decomposition.
Sulfate (SO₄ ²⁻), the most oxidized form of sulfur (+6), is reduced by these
sulfate-reducing bacteria. The end product of sulfate reduction is hydrogen sulfide, H₂S, (oxidation number -2) an important natural product that participates in many biogeochemical processes. The H₂S they generate is responsible for the pungent smell (like that of rotten eggs) often encountered near coastal ecosystems. When sulfate-reducing bacteria grow, the H₂S formed from SO₄ ²⁻ reduction combines with the ferrous iron to form black, insoluble ferrous sulfide, which is not toxic. This is important for the conservation of the environment.
b) The net ionic equation under acidic conditions is:
4 H₂ + SO₄²⁻ + H⁺ → HS⁻ + 4 H₂O
Global reaction: SO₄²⁻ + 2H⁺ → H₂S + O₂
A 558 mg of a mixture of fluorene and benzoic acid was weighed out and subjected to an extraction and recrystallization. After this purification was completed the product crystals were dried and analyzed. The purification procedure produced 185 mg of fluorene and 144 mg of benzoic acid. Calculate the percent composition of this mixture.
Answer:
See explanation
Explanation:
Mass of mixture of fluorene and benzoic acid = 558 mg
Mass of pure fluorene after purification = 185 mg of fluorene
Mass of pure benzoic acid after purification = 144 mg of benzoic acid
Percentage of fluorene int he mixture = 185mg/558mg * 100 = 33.15 %
Percentage of benzoic acid in the mixture = 144mg/558mg * 100 = 25.81 %
Percentage of impurities = 100% - [33.15 + 25.81]
Percentage of impurities = 100 - 58.96
Percentage of impurities = 41.04 %
Consider the following data:
HfCo2 = -393.5 kj/mol
HfH20 = -241.82 kj/mol
Hfc2h6 = -84.68 kj/mol
Using these data, calculate Delta HRXN
for this chemical reaction. Round to the nearest whole number.
2C2H6(g) + 7O2(g) -> 4CO2(g) + 6H2O(g)
Answer:
if you ask yahoo answers it will tell you
Explanation:
hope i helped
Answer:
-2856
-792
endothermic, exothermix, exothermic, endothermic
no
Explanation:
Shown below is a table with plants and animals with their adaptations.
Using the description of plants and animals in the table above, which biome would all of these organisms would be best adapted to?
Answer:
Desert
Explanation:
The adaptation shown by the given plants and animals shows that they will adapted to the desert biome.
It is so because, due to high temperature of desert some desert animals like camel have the storage of fat in humps or tails; some animals have large ears such as Jackrabbits, it helps to release body heat and adapt in high temperature; plants have thick water holding tissues to reduce water loss in heat and waxy coating that keeps the plants cooler and reduce moisture loss.
Hence, the correct answer is "Desert".