Answer:
The valency of a molecule is zero.
Explanation:
Valency is calculated by calculating number of electrons present in outermost orbitals of atom of element.
Hope it is helpful.....how does calcium atomic radius compare to magnesium (Mg) radius and patssiuks (K) redius?
Answer:
The radius of a calcium atom would be larger than that of a magnesium atom.
The radius of a calcium atom would be slightly smaller than that of a potassium atom.
Explanation:
Refer to a modern copy of the periodic table.
Calcium and magnesium are in the same column. They are in the same group (IUPAC group [tex]2[/tex].)
Hence, atoms of calcium and magnesium would have similar effective nuclear charges. In other words, the attraction between a calcium atom nucleus and its valence electrons would be similar to that of magnesium.
However, calcium is in the fourth row of the periodic table (fourth period) while magnesium is in the third (third period.) A calcium atom would thus have four main shells with electrons. In contrast, a magnesium atom would only have three such main shells.
Despite the similar effective nuclear charge (effective attraction on the outermost electrons,) the radius of a calcium atom would be larger than that of a magnesium atom because of the extra main electron shell.
On the other hand, calcium and potassium are in the same row (same period.) A calcium atom and a potassium atom would both include four electron-filled main shells.
However, with one additional proton per atom, the effective nuclear charge of calcium atoms would be greater than that of potassium atoms. Hence, when compared to potassium nuclei, the nucleus of a calcium atom would pull its electron shells closer to the center. The radius of a calcium atom would thus be smaller than that of a potassium atom.
In general, atomic radius would generally become larger when moving down a column in the periodic table. On the other hand, atomic radius would general become smaller when moving towards the right-hand side of a row in the periodic table.
i will mark brainliest if you are correct
Which statement about pure substances and elements is correct?
a
All pure substances are elements.
b
All elements are pure substances.
c
Pure substances cannot be elements.
d
Elements cannot be pure substances.
The statement about pure substances and elements correct is all elements are pure substances ,therefore option (b) is correct .
What do you mean by the elements ?An element is a pure substance whose atoms all have the same number of protons.
Elements are the simplest chemical elements and thus can not be broken down through chemical reactions.
Characteristics of element -:
Elements cannot be broken down into simpler substances by the chemical reactions. Each element is represented by a unique symbol.The atomic number gives a distinct identity to a chemical element.The statement about pure substances and elements correct is all elements are pure substances ,therefore option (b) is correct .
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How could you describe the changes that happen when carbon changes form from graphite to diamond
-it is a chemical change, but the intensive and extensive properties of carbon will be maintained
-it is a physical change, but the intensive and extensive properties of carbon will be maintained
-it is a chemical change, which could change some of the intensive and extensive properties of the carbon
-it is a physical change, which could change some of the intensive and extensive properties of the carbon
The correct answer is: it is a chemical change, which could change some of the intensive and extensive properties of the carbon.
To answer this question, we must bear in mind that a chemical change involves the breaking of bonds in a substance and subsequent rearrangement of atoms to form a new substance.
This is why we say that in a chemical change, new substances are formed. Another name for a chemical change is a chemical reaction.
Having said that, it is clear that as graphite changes to diamond, bonds are broken and carbon atoms are rearranged.
This rearrangement of atoms leads to different intensive and extensive properties for graphite and diamond. For instance, graphite conducts electricity but diamond does not conduct electricity. Also, diamond is much denser and harder than graphite. A physical change can not lead to change in some of the intensive and extensive properties of the carbon.
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What distinguishes a chemical property from a physical property?
A. Chemical properties describe the characteristics of a substance that are directly observable without changing the substance.
B. Chemical properties are only observable when a substance changes into a new substance.
C. Chemical properties always change depending on temperature or pressure.
D. Chemical properties only describe subjective characteristics that cannot be measured with scientific tools.
C. Chemical properties always change depending on temperature or pressure.
Physical Change v/s Chemical Change:
Physical changes are reversible in nature while chemical change leads to the formation of new products.No new substance is formed in a physical change while it occurs in case of chemical change.A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance while a chemical property describes the ability of a substance to undergo a specific chemical change.When the reactants are mixed, the temperature change caused by the reaction is an indicator of a chemical change. Thus we can say that chemical properties always change depending on temperature or pressure.Learn more:
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3
A substance dissolves in water to form a colourless solution. This solution reacts with aqueous
silver nitrate in the presence of dilute nitric acid to give a yellow precipitate.
What is the possible identity of the substance?
A А
calcium iodide
B
copper(II) chloride
Ciron(II) iodide
D
sodium chloride
Answer:
D) sodium chloride
i think this is the answer
Explanation:
The equation shows the reaction of sulfuric acid with sodium hydroxide:
H2SO4 + 2NaOH --> NaSO4 + 2H2O
25 cm^3 of sulfuric acid of concentration 0.2 mol/dm^3 reacted with exactly 10 cm^3 of sodium hydroxide. Calculate:
a) the number of moles of sulfuric acid present
b) the number of moles of sodium hydroxide reacting
c) the concentration of the sodium hydroxide in mol/dm^3
Answer:
(a).
[tex]{ \sf{1000 \: {cm}^{3} \: contains \: 0.2 \: moles \: of \: acid}} \\ { \sf{25 \: {cm}^{3} \: contains \: ( \frac{25 \times 0.2}{1000} ) \: moles}} \\ \\ = { \sf{0.005 \: moles}}[/tex]
» 0.005 moles of sulphuric acid are present.
(b).
from the equation:
[ 1 mole of acid reacts with 2 moles of sodium hydroxide ]
[tex]{ \sf{1 \: mole \: of \: acid \: reacts \: with \: 2 \: moles \: of \: hydroxide}} \\ { \sf{0.005 \: moles \: of \: acid \: react \: with \: (0.005 \times 2) \: moles}} \\ { \sf{ = 0.01 \: moles}}[/tex]
» 0.01 moles of sodium hydroxide reacted.
(c).
[tex]{ \sf{10 \: {cm}^{3} \: contains \: 0.01 \: moles \: of \: hydroxide }} \\ { \sf{1000 \: {cm}^{ 3} \: contain \: ( \frac{1000 \times 0.01}{10} ) \: moles}} \\ \\ { \sf{ = 1 \: mol \: {l}^{ - 1} }}[/tex]
» concentration is 1 M
Help me with this easy chemical change question!!!!
Answer:
1, just I) color.
Physical properties are the properties that can be observed without changing the composition of a substance, such as color, temperature, density, and boiling point.
A physical change is a change in the substance that only modifies its aggregation state, such as solidification, and boiling.
Chemical properties are the properties that need a reaction to being observed, such as combustibility, which needs a combustion reaction to being quantified.
When a chemical reaction occurs, and the composition of the substance change, it's a chemical change.
So, heating copper with carbon is a chemical reaction, and purification by electrolysis is too. Color is the only physical property.
1. A (blank) determines what will be tested in a scientific experiment.
Answer:
Hypothesis
Explanation:A hypothesis is what gives the user the directions of the lab and what needs to be done for the procedure
Engineers use scientific knowledge to help them design solutions to problems. GUK (sodium polyacrylate) is a chemical with some unusal properties. Think of a community problem or a global problem that could benefit from the properties of GUK. Discuss your vision of how GUK could be used to solve this problem in 3-5 sentences.
Sodium can be used to solve the problem of
Water pollutionSodium polyacrylate is a sodium salt of polyacrylic acid. It is a super absorbent polymer (SAP) that has great adsorption abilities enabled by the presence of sodium. These abilities find great application in many consumer products as it solves a lot of problems.
Metal ions can be removed from water in industries and water bodies using sodium polyacrylate because it has the ability to increase the surface area of porous substances so that there can be more transfer of mass.
Summarily, the problem of metal ions in water which causes pollution can be solved using GUK.
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What correctly describes the melting of a solid
The particles in the solid LOSE enough energy to OVERCOME the interactions between the particles
The particles in the solid GAIN enough energy to FORM the interactions between the particles
The particles in the solid GAIN enough energy to OVERCOME the interactions between the particles
The particles in the solid LOSE enough energy to raise the temperature of the solid enough to turn it into a
liquid
Answer:
A reaction in which heat is absorbed by reactant molecules and energy of products become more than reactants is known as an endothermic reaction
What does the atomic number of an element represent?
A. number of isotopes
B. number of protons
C. number of bonds
D. number of atoms
Answer:
protons
Explanation:
btw you protons and electrons are always the same
prcAnswer:
e c. proton
Explanation:
i pueslist
This scale is being used to measure flour. What is the
scale really measuring about
the flour?
A. the color of the flour
B. the volume of the flour
C. the weight of the flour
D. the temperature of the
flour
What are the uses of hydrogen?
Answer:
Hydrogen finds a variety of application due to its dual nature. Following are some important uses of hydrogen:
Hydrogen is used in the synthesis of ammonia and the manufacture of nitrogenous fertilizers.
Hydrogenation of unsaturated vegetable oils for manufacturing vanaspati fat.
It is used in the manufacture of many organic compounds, for example, methanol.
Hydrogen chloride is a very useful chemical and is prepared from hydrogen.
Hydrogen can reduce many metal oxides to metals by metallurgical processes.
Hydrogen is used as rocket fuel in many space research activities.
Hydrogen fuel is being experimented within the automotive industry with hydrogen fuel cells.
Please help!
Best answer with explanation will be marked brainliest.
Explanation:
I think it is d because it is a gas
descoberto em 1996 por pesquisadores alemães o novo elemento químico de numero 112 poderá ser batizado de copernicium em homenagem ao cientista e astronomo Nicolau Copérnico segundo os cientistas o elemento é aproximadamente é 277 vezes mais pesado que o hidrogênio, o que torna o elemento mais pesado da tabela periódica ocupando a posição relativaa ao 7°periodo do grupo 12. A tabela periódica, uma das realizaações mais notáveis da quimica, foi desenvolivda exclusivamente a partir das propriedades fisícas e químmicas dos elementos e, por isso, o conhecimento da posição ocupada por um elemento químico permite que se façam algumas previsões quanto às suas propriedades.
considerando a localização dos átomos dos elementos químicos x, y e z na tabela periódica é incorreto afirmar que
x = 3° período do grupo 1 (I A)
y = 2° período do Grupo 14 (IV A)
z = 2° período do grupo 16 (VI A)
Answer:
Loading...
Explanation:
How does the amount of oxygen in the water affect the oyster population constant/variables and what is the hypothesis/predication
Answer:
Lack of oxygen can cripple the oysters' ability to fight off the parasite Perkinsus marinus that causes Dermo and slowly takes over their bodies.
HELP ME THIS IS FOR TODAY!!!!!
Answer:
4. 0.5 kilometers (1st option)
5. 0.1 00 liters (last option)
Explanation:
500 meters to kilometers
4.
1 kilometer = 1000 meters
We use the formula SBD (SMALL TO BIG DIVIDE) i hope this helps you
500 ÷ 1000
= 0.5 kilometers
5.
100 milliliter to liter
SBD
100 ÷ 1000
= 0.1 00 liters
Polar molecules have partial positive and partial negative charges. An electrical
attraction between the partial positive charge of one polar molecule and the partial
negative charge of another polar molecule is called a/an
Answer:
Image result for Polar molecules have partial positive and partial negative charges. An electrical attraction between the partial positive charge of one polar molecule and the partial negative charge of another polar molecule is called a/an
A polar molecule has a net dipole as a result of the opposing charges (i.e. having partial positive and partial negative charges) from polar bonds arranged asymmetrically. Water (H2O) is an example of a polar molecule since it has a slight positive charge on one side and a slight negative charge on the other.
Explanation:
Calculate the empirical formula of a compound that has a composition of 5.9% (by mass) hydrogen and 94.1% (by mass) oxygen.
Answer:
[tex]oxygen \: at \: 94.1\% \: hydrogen \: at \: 5.9\% \\ at \: 100gram \: oxygen \: \\ \: 94.1\% = .941 \times 100g \\ = 94.1 \times \frac{1mol}{16g} = 5.88g \\ hydrogen \: \\ 5.9\% = .059 \times 100 = 5.9 \times \frac{1mol}{1.002g} = 5.88g \\ here \: oxygen = hydrogen \: so \: ratio \\ = 1 \: \: \: 1 \: \\ emperical \: formula \: = oh\\ thank \: you[/tex]
Composition:
5.9% Hydrogen and 94.1% Oxygen (by mass)
in a 100 gram sample:
5.9 gram Hydrogen
94.1 gram Oxygen
Finding the number of moles:
Moles of Hydrogen:
moles = given mass/ molar mass
moles = 5.9 / 1 [molar mass of Hydrogen = 1g/mol]
moles of hydrogen = 5.9 moles
Moles of Oxygen:
number of moles = given mass / molar mass
number of moles = 94.1 / 16 [molar mass of Oxygen = 16g/mol]
moles of Oxygen = 5.88 ≈ 5.9 moles
Empirical Formula:
Moles of Hydrogen : Moles of Oxygen
5.9 : 5.9
Moles of Hydrogen : Moles of Oxygen = 1:1
Empirical Formula = OH
You want to determine the effect of a certain fertilizer on the growth of orchids grown in a greenhouse.
Materials that are available to you include: greenhouse, 100 orchid plants, water, fertilizer, and soil. You
want to know if the orchids will hgrow best with a weak concentration of fertilizer, a medium concentration
of fertilizer, or a high concentration of fertilizer. How will you design an experiment to test different
concentrations of this fertilizer?
how do you set up a controlled experiment
difference between atom and ion
plz plz answer
Answer:
Atoms are neutral; they contain the same
samenumber of protons as electrons. By
definition, an ion is an electrically charged
particle produced by either removing
produced by either removingelectrons from a neutral atom to give a
produced by either removingelectrons from a neutral atom to give apositive ion or adding electrons to a neutral atom to give a negative ion.
A gas occupies 250mL, and it's pressure is 0.724 atm at 25 degrees c.r = 0.0821 L•atm/mol•k. Solve for moles !! Plzzzz
Answer:
0.0074 moles
Explanation:
We'll have to use this forumla: PV = nRT
P = Pressure (0.724)
V = Volume in liters (0.25)
n = moles
R = 0.0821
T = temperature in kelvins (25 + 273 = 298)
Our equation will look like this:
(0.724)(.25) = n(0.0821)(298)
0.181 = 24.4658n
Divide both sides by 24.4658 to isolate n
0.181/24.4658 = 24.4658n/24.4658
n = 0.00739808
What series does the following compound belong to?
Answer:
B
Carboxylic acid
Explanation:
I'm not entirely sure, but this should be it
Someone plz help me !!
Science
Or
Bias?
Which element would most likely lose electrons to form positive ions when bonding with other elements?
rubidium (Rb)
gallium (Ga)
argon (Ar)
iodine (I)
The correct answer to the question is Rubidium (Rb)
Rubidium (Rb) is a group 1 element and as such, it can form bond by losing it's valence electron (i.e 1 electron) easily.
Gallium (Ga) is a group 13 element. It can only form bond by losing it's 3 valence electrons.
Argon is a group 18 element. This group has completely filled outermost shell and are very stable. They do not involve in bond formation.
Iodine (I) is a group 17 element. It is more difficult for this group to lose its 7 valence electrons hence, they form bond by accepting 1 electron.
With the above information, we can conclude that Rubidium will most likely lose electron to form bond.
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Answer:
(Question 1)Which element would most likely lose electrons to form positive ions when bonding with other elements?
(Answer) rubidium (Rb)
(Question 2) Which statement about sodium chloride is correct?
(Answer) The sodium atom transfers electrons to the chlorine atoms to form ionic bonds.
(Question 3) Based on their locations in the periodic table, which two elements are most likely to form covalent bonds with each other?
(Answer) nitrogen (N) and oxygen (O)
(Question 4) Which phrase best describes electronegativity?
(Answer) the relative strength with which an element attracts electrons in a chemical bond
(Question 5) Based on the information in the table, which pair of elements would likely form the least polar bonds with each other?
(Answer) bromine and nitrogen
Explanation:
just finished the quick check enjoy UwU
what is the molecular weight of H2so4?
Lets find
[tex]\\ \sf\longmapsto H_2SO_4[/tex]
[tex]\\ \sf\longmapsto 2(1u)+32u+4(16u)[/tex]
[tex]\\ \sf\longmapsto 2u+32u+64u[/tex]
[tex]\\ \sf\longmapsto 34u+64u[/tex]
[tex]\\ \sf\longmapsto 98u[/tex]
A factor is an experiment that can change is a(n)
Answer:
Option 2 variable
Explanation:
Answer:
variable.
Explanation:
A variable is anything that can change or be changed. In other words, it is any factor that can be manipulated, controlled for, or measured in an experiment.
A student is working hard on a chemistry lab experiment that uses a strong acid. Halfway through the lab, the student gets hungry and starts eating a bag of chips. When the student licks their fingers, they start to have a severe reaction. summary
A brick has a mass of 100 G and a volume of 25CM3 what is the density of the brick
Answer:
[tex]\boxed {\boxed {\sf 4 \ g/cm^3}}[/tex]
Explanation:
We are asked to find the density of a brick. Density is a substance's mass per unit volume. The formula for calculating density is as follows.
[tex]\rho= \frac{m}{v}[/tex]
The mass of the brick is 100 grams and the volume is 25 cubic centimeters.
m= 100 g v= 25 cm³Substitute the values into the formula.
[tex]\rho= \frac{ 100 \ g}{25 \ cm^3}[/tex]
Divide.
[tex]\rho=4 \ g/cm^3[/tex]
The density of the brick is 4 grams per cubic centimeter.
What is your experience in stars??
Answer:
Experience in star is very nice
Explanation:
Because i love stars