Answer:
changes from a solid to a liquid
Explanation:
C- A solid is being formed
Since the delta is negative, this indicates that a substance is transforming from a liquid state to a solid state. This best corresponds with C- A solid is being formed.
Which if the following matters occupies more space, assuming similar number of molecules? A.(Solid) B.(Liquid) C.(Gas) D. (Solid and gas)
Why is John Dalton known as the originator of atomic theory?
Answer:
he thought of atoms first
Answer:
He was the first to be the one to propose that matter is made out of atoms. He also proved that the atoms are divisible in nature.
10) What does mRNA copy and carry the code to produce? (1pt)
a) DNA
b) Proteins
Answer:
a
Explanation:
If the pH of a solution is 9, the solution is A. acidic, which turns phenolphthalein pink B. acidic, which turns phenolphthalein colorless C. basic, which turns phenolphthalein pink D. basic, which turns phenolphthalein colorless
Answer:
C.
Explanation:
pH > 7, basic, so pH = 9 is basic.
When solution is basic, it will turn phenolphthalein pink.
A piece of lithium metal is added to a beaker that contains water and phenolphthalein. Using what you know about the properties of bases, choose the best explanation for what you observe.
Answer:
The phenolphthalein is turning pink because a base is forming.
Complete the table to summarize the properties of the different subatomic particles by typing in 'yes"
or "no."
A
Answer:
A=yes
B=yes
Explanation:
Just did the same thing
Protons and neutrons are made of quarks but electrons are not. So A is yes, B is Yes and C is No.
What are quarks?
Quarks are extremely small substances which join with each other by extremely strong forces and makeup neutrons and protons of the atom. They combine in a similar way that the protons and neutrons combine to form the nucleus of an atom.
Quarks are categorized in flavours and there are 6 different types of flavours of quarks. The flavours differ from each other on the basis of their charge and mass.
The six flavours of quarks are grouped as three pairs. These are up and down, charm and strange and top and bottom.
Quarks are defined as true elementary particles. They have no defined structure and cannot be subdivided into smaller particles.
Therefore, the correct option is A is yes, B is Yes and C is No.
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1) How much energy would be required to melt 15.0 g of ice at 0°C?
= 334 J/g)
(AH fusion
Answer:
5010J
Explanation:
The following data were obtained from the question:
Mass (m) = 15g
Heat of fusion (ΔHf) = 334J/g
Heat required (Q) =..?
The heat energy required to melt the ice can be obtained as follow:
Q = m·ΔHf
Q = 15 x 334
Q = 5010J
Therefore, the heat energy required to melt the ice is 5010J.
Which of the following statements is true? Less rain and snow falls in smoky areas than in other areas. Acid rain causes corrision of buildings and statues. The first laws againts pollution were passed in the 1990s. Cars are the leading cause of nitrogen oxide pollution.
Answer:
Acid rain causes corrosion in buildings.
Explanation:
This is true because acid rain over time can eat away at the building.
describe an experiment to show water is an oxide to hydrogen
Answer:
2H + O -------> H2O
and hydrogen react with oxygen so it is oxide of hydrogen
like iron react with Oxygen and give
iron oxide
Explanation:
after passing electric current in the water the two gases will get seperated and on bringing the matchstick close to hydrogen it will burn with a pop sound
I need this fast plz, 50 points
By doing which action will you decrease the number of collisions and energy of reactant molecules?
A.) decreasing the temperature of the reactant mixture
B.) increasing the pressure of the reactant mixture
C.) decreasing the concentration of reactants
D.) adding a catalyst
Answer:
It is decreasing the temperature of the reactant mixture.
Explanation:
Just took the test
In order to decrease the number of collisions and energy of reactant molecules, the temperature of the reactant mixture would need to be decreased as well.
Temperature of reactantsThe temperature of reactants is proportional to the average kinetic energy of the molecules of the reactants.
Also, the higher the average kinetic energy of the reactant molecules, the higher their chances of colliding and reacting to form products.
Thus, in order to decrease their energy and collision frequency, the temperature of the reactant mixture needs to be decreased.
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How many moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C? The freezing point depression constant for water is 1.86°C•kg/mol. What is the molality of the solution?
Answer: 1.29 moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C. Molality of solution is 1.29 m.
Explanation:
Depression in freezing point is given by:
[tex]\Delta T_f=i\times K_f\times m[/tex]
[tex]\Delta T_f=T_f^0-T_f=(0-(-2.4))^0C=2.4^0C[/tex] = Depression in freezing point
i= vant hoff factor (for non electrolyte , i = 1)
[tex]K_f[/tex] = freezing point constant for water= [tex]1.86^0C/kgmol[/tex]
m= molality =[tex]\frac{\text{moles of solute}}{\text{weight of solvent in kg}}[/tex]
m= molality =[tex]\frac{x}{1kg}[/tex]
[tex]2.4^0C=1\times 1.86^0C/kgmol\times \frac{x}{1kg}[/tex]
[tex]x=1.29[/tex]
Molality = [tex]\frac{\text{moles of solute}}{\text {weight of solvent in kg}}=\frac{1.29mol}{1kg}=1.29m[/tex]
Thus 1.29 moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C. Molality of solution is 1.29 m.
Answer:
1) C (m=T f/Kf)
2) 2.4 C
3) 1.3 m
4) 1.3 moles
Explanation:
This is correct on ed
The compound represented by this formula can be classified as an
Answer:
It depends what formula you are talking about.
Explanation:
please further explain so I can be sure.
Reply ASAP: Why do electrons affect the structure of a molecule?
A. Bonding pairs are positively charged and lone pairs are negatively charged and they push each other into certain shapes.
B. They do not.
C. The electron clouds are negatively charged and repel each other as far apart as possible.
D. Bonding pairs are negatively charged and lone pairs are positively charged and they push each other into certain shapes.
Answer:
C. The electron clouds are negatively charged and repel each other as far apart as possible
Explanation:
This is the basis of VSEPR theory.
The angles between the electron clouds determine the shapes of the molecules.
B. and D. are wrong. All electron pairs are negatively charged.
The electrons affect the structure of a molecule because the bonding pairs are positively charged and lone pairs are negatively charged and they push each other into certain shapes.
What is the shape of an atom?Every atom or molecule consist some kind of geometry or shapes like linier, tetrahedral, square planner, octahedral etc. with some bond length and angles present with them.
The bond pairs in a geometry is made up with positive charge and lone pairs present on the atom in the form of negative charge as they both are opposite in nature and repel or push each other in opposite direction.
Due to this phenomena the structure of the atom gets effected and geometry will change on the basis of lone pair and bond pair repulsion.
Therefore, electrons affect the structure of a molecule because the bonding pairs are positively charged and lone pairs are negatively charged and they push each other into certain shapes.
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Which is true of transition metals when moving from left to right on the periodic table
Answer:
D
Explanation:
Atomic radii decrease slightly and then start to increase.
Atomic radius of transition metals from left to right increases slightly then decreases. Thus it is not following the trend as for other periods. Hence, option c is correct.
What are transition metals?Transition metals are d-block elements in periodic table. starting from group 3 to group 12. Transition metals are called so because they are in between gases and metals in periodic table.
All transition metals shows varying oxidation states. For example, iron Fe shows +2 and +3 and copper shows +1, +2 and +3. Transition metals are malleable, ductile and are good conductors of heat and electricity.
From left to right in a row in periodic table, the atomic radius decreases and electronegativity increases. However, this trend is not systematic in the case of transition metals where, the atomic radii increases first and then decreases.
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Your question is incomplete, but your complete question probably was:
Which is true of transition metals when moving from left to right on the periodic table
The d sublevels are not filled across the period.
The cation radii become larger across the period.
Atomic radii increase slightly and then start to decrease.
Atomic radii decrease slightly and then start to increase.
___and ___exert pressure on the walls of the vessel in which they are carried out
A) Solid, liquid and Gases
B) Gases and solids
C) Liquids and gases
D) Solid and gases
Answer:
C) Liquids and gases
Explanation:
The correct answer would be liquids and gases.
The molecules of liquids and gases move randomly when held in a container. The random movement causes a collision between the molecules of the liquids/gases and between the walls of the container, creating pressure in the process. This is unlike the molecules of solids that vibrate about fixed positions.
Hence, the correct option is C.
what part of the brain helps you see and think
Answer:
Mark me brainliest
How many atoms or molecules are in 5.0 moles of the following?
a. O
b. N
c.MgCl₂
d. C₂H₃NO
Answer:
They all have the same number of molecules or atoms which is 3.011*10²⁴ molecules or atoms.
5 moles of O = 3.011*10²⁴ molecules or atoms
5 moles of N = 3.011*10²⁴ molecules or atoms
5 moles of MgCl2 = 3.011*10²⁴ molecules or atoms
5 moles of C2H3NO = 3.011*10²⁴ molecules or atoms.
Explanation:
a)
5 moles of O = ?
1 mole of any substance is equal to Avogadro's number which is equal to 6.022×10²³molecules or atoms
From the question above,
5 moles of O = 5 × 6.022*10²³ = 3.011×10²⁴atoms or molecules.
b)
5 moles of N
From the same principle or fundamentally stated fact above,
1 mole of any substance = 6.022*10²³molecules or atom
5 moles of N = 5 × 6.024
2*10²³ = 3.011*10²⁴atoms or molecules.
c)
5 moles of MgCl₂
Same principle we used in a and b,
1 mole of any substance = 6.022*10²³ atoms or molecules
5 moles of MgCl2 = 5.0×6.022*10²³ = 3.011*10²⁴ atoms or molecules.
d)
5 moles of C₂H₃NO = ?
1 mole of C₂H₃NO = 6.022*10²³molecules or atoms
5 moles = x molecules or atoms
x = 5 × 6.024
2*10²³ = 3.011*10²⁴ atoms or molecules
What this proves is that no matter the compound, molecule or element, as long as they have equal amount of moles, they'll have the same number of atoms, molecules or particles.
Answer:
a. 3.011x10²⁴ atoms of O in 5 moles.
b. 3.011x10²⁴ atoms of N in 5 moles.
c. 3.011x10²⁴ atoms of MgCl₂ in 5 moles.
d. 3.011x10²⁴ atoms of C₂H₃NO in 5 moles
Explanation:
A mole is defined as the number of atoms in exactly 12.000g of ¹²C.
This number is equal to 6.022x10²³. That means 1 mole is equal to 6.022x10²³.
Thus:
a. O . 5 moles of oxygen (An atom) are:
5 moles O ₓ (6.022x10²³ atoms of O / mole) = 3.011x10²⁴ atoms of O in 5 moles
b. N . Also, 5 moles of nitrogen are:
5 moles N ₓ (6.022x10²³ atoms of N / mole) = 3.011x10²⁴ atoms of N in 5 moles
c. MgCl₂ . Magnesium chloride is a molecule. Again, 1 mole of MgCl₂ contains 6.022x10²³ molecules and 5 moles are:
5 moles MgCl₂ ₓ (6.022x10²³ molecules of MgCl₂ / mole) = 3.011x10²⁴ atoms of MgCl₂ in 5 moles
d. C₂H₃NO. 5 moles of C₂H₃NO are:
5 moles C₂H₃NO ₓ (6.022x10²³ molecules of C₂H₃NO / mole) = 3.011x10²⁴ atoms of C₂H₃NO in 5 moles
As you can see, number of molecules of 1 mole doesn't depend on the nature of the substance.
Which represents the greatest time frame in which a short-term environmental change can occur?
in days
O in minutes
O over hundreds of years
O over thousands of years
Answer:
in days
Explanation:
A short term environmental change refers to changes in the environment that happens within a short period of time, for example, flooding, drought, volcanic eruptions etc. In contrast to short term environmental change, long term environmental change takes place over a long period of time hence species have a longer time to adapt to it. Short term environmental changes may or may not be caused by humans. An example of a short term environmental change caused by humans is oil spillage. Short term environmental changes may lead to the the migration of species from the ecosystem.
Short term environmental changes usually occur within a very short time. The greatest time frame in which a short term environmental change can occur is in a matter of days. Only longterm environmental changes span hundreds and thousands of years.
Answer:
it is c
Explanation:
i took the test :)
I NEED HELP PLEASE, THANKS! :)
Explain the process of sublimation. Name one substance that sublimes at room temperature and pressure.
Answer:
Here's what I get
Explanation:
Sublimation is the conversion of a solid directly to a gas, without passing through the liquid state.
It occurs when the molecules of a solid have absorbed enough heat (kinetic energy) for some molecules to overcome the attractive forces of their neighbours and escape directly into the vapor phase.
One substance that sublimes at room temperature and pressure is CO₂ (dry ice).
Naphthalene is a substance that sublimes at room temperature and pressure.
What do you mean the process of sublimation ?Sublimation is defined as a process in which solid converts into gas directly without converting into liquid.
In the sublimation process, the reaction is an endothermic reaction, as the chemical bonds between molecules are broken down in order to release them into the air. Therefore ,the energy is released and so it is an endothermic reaction.
The heat or energy required to change the state from solid to gas is called the enthalpy of sublimation .Generally, it is expressed as KJ/m o l. Sublimation only occurs at pressures and temperatures .
Hence , Naphthalene is a substance that sublimes at room temperature and pressure.
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the general formula for the alkane series is:
Answer:
The alkanes comprise a series of compounds that are composed of carbon and hydrogen atoms with single covalent bonds. This group of compounds comprises a homologous series with a general molecular formula of C n H 2 n+2 , where equals any integer.
Explanation:
The general formula for the alkane series is CnH2n+2
General formula for the alkane series:In this formula:
"Cn" shows how many carbon atoms are in the alkane molecule.
"H2n+2" shows the amount of hydrogen atoms in the alkane compound, with "n" being the number of carbon atoms.
Alkanes are a group of hydrocarbons that only have single bonds between their carbon atoms. The formula says that each carbon atom is connected to two hydrogen atoms. And the total number of hydrogen atoms in an alkane molecule is two more than double the number of carbon atoms.
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Both E. coli and Salmonella are single-celled organisms. They do not have a nucleus or other membrane-bound organelles. Based on the concept of domains, what do they have in common? They both belong to kingdom Fungi. They both belong to domain Eukarya. They both belong to domain Bacteria. They both belong to kingdom Animalia.
Answer:
domain bacteria
Explanation:
Salmonella and E. coli are same in the sense that they are both bacteria,
Answer:
B
Explanation:
polarity of the molecules increase with electro nogativity
Answer:
true
Explanation:
polarity of the molecules increased with electronegatiy it's true
What is the molarity of a solution prepared by dissolving 7.0 moles of NaCl solute in 585 ml of solution
?
Answer:
12 mol/L
Explanation:
Molarity = moles/L solution = 7.0 mol /0.585 L ≈ 12 mol/L
Condensation refers to the process when
A gas turns to a liquid
A liquid turns to a gas
A liquid turns to a solid
A solid turns to a liquid
Answer:
A Gas turns to a liquid
Explanation:
Kaia, a chemical engineering graduate, has documented all titration procedures in her project report. She refers to this report while performing titrations in her laboratory. This is an example of _____. Select one: a. muted knowledge b. implied knowledge c. tacit knowledge d. explicit knowledge
Answer:
The correct option is;
d. Explicit knowledge
Explanation:
Explicit knowledge is the knowledge that can be easily articulated documented stored in a retrieval system accesses, transmitted and shared with others
Tacit knowledge is the skill developed by an individual based on actual experience such that such knowledge comprise of both facts and perspectives
Hence explicit knowledge and tacit knowledge are complementary
The operations performed by Kaia include documentation, storing in a retrieval system (her project report) and accessing what she documented, this is an example of explicit knowledge.
name two bases which react with dillute sulfuric acid to give zinc sulfate
Answer:
Zinc Carbonate
Zinc Nitrate
Explanation:
Someone please help me!!
Answer:
the 3rd one (0.01 cm the one selected already)
Explanation:
copper wire isn't excessively big, and it wraps around the pencil because its malleable. I think that the most accurate would be 0.01 cm
a student balanced the chemical equation for the reaction of magnesium with oxygen by writing Mg + O2 ----> MgO2. What is wrong with this equation?
Answer:
Explanation:
Magnesium when it oxidizes has a valence of 2.
Oxygen, when it mixes with something, has a valence of - 2
So Mg and O2 will form something, but what? The answer is MgO
Mg + O2 ===> MgO
To balance this equation, you need 2 Magnesiums on the right and 2 Oxygens also on the right. The left will need a two Magnesiums.
The balanced equation will be
2Mg + O2 ====> 2MgO
If a 200 g piece of aluminum has a density of 5.0 g/cm^3. what is its volume?
Answer:
Volume=mass in g /density
Answer: 40cm^3 or 40ml
Explanation:
[tex]Density=\frac{mass}{volume}[/tex]
so 5=200/V
V=200/5
V=40cm^3
50 POINTS! Fill in the chart below to identify and describe the functional groups associated with organic chemistry.
Name General Structure Properties/Uses
Alcohol
Aldehyde
Ketone
Fatty acid
Ether
Answer:
Alcohol
Structure: Alcohols are organic molecules assembled from carbon (C), oxygen (O), and hydrogen (H) atoms.
Property: The Boiling Point of Alcohols. Alcohols generally have higher boiling points in comparison to other hydrocarbons having equal molecular masses.
Aldehyde
Structure: DescriptionAn aldehyde is a compound containing a functional group with the structure −CHO, consisting of a carbonyl centre.
Property: The polarity of the carbonyl group notably affects the physical properties of melting point and boiling point, solubility, and dipole moment.
Ketone
Structure: A ketone is a functional group with the structure RC(=O)R', where R and R' can be a variety of carbon-containing substituents.
Property: Ketones are soluble in water but their solubility decreases with increase in the length of the chain.
Fatty Acid
Structure: a fatty acid consists of a straight chain of an even number of carbon atoms, with hydrogen atoms along the length of the chain and at one end of the chain and a carboxyl group (―COOH) at the other end.
Property: Fatty acids are solid at room temperature, while unsaturated fatty acids are liquid.
Ether
Structure: a class of organic compounds characterized by an oxygen atom bonded to two alkyl or aryl groups.
Property: An ether molecule has a net dipole moment due to the polarity of C-O bonds.
The functional group associated with ethanol is -OH, the aldehyde is -COH, the ketone is -CO, the fatty acid is -COOH, and ether is ROR.
The functional groups have been the atoms that have different constituents and properties with respect to other groups.
The functional group associated with the following groups has been:
Alcohol: It has been liquid at room temperature with the functional group -OH.Aldehyde: It has been soluble in water with the functional group -COH.Ketone: It has been soluble in water, with C=O in the structure as a functional group.Fatty acid: It has been a long chain acid, with the presence of carboxylic group -COOH.Ether: It has been the pleasant smelling compounds with the presence of the R-O-R group as the functional group.
The functional group associated with ethanol is -OH, the aldehyde is -COH, the ketone is -CO, the fatty acid is -COOH, and ether is ROR.
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can a substance be a lewis acid without being a bronsted-lowry acid?argue
Answer:
Yes
Explanation:
Yes, A substance can be a lewis acid without being a Bronsted-Lowery acid because there are some substances which cannot donate protons(Bronsted-Lowery acid) but can accept a pair of electron.
For Example:
Let us take the example of BF₃
BF₃ contains no proton so it is not a Bronsted Lowery Acid
However, BF₃ has an incomplete octet with 6 electrons. It needs an electron pair to complete its octet. It accepts a pair of electron to become a Lewis Acid
Answer:
Interesting question, and the answer is yes, a substance can be a Lewis acid but not a Bronsted-Lowrey acid. To see this, let’s take a look at the definitions of each.
Explanation:
Bronsted-Lowrey acid:
A compound that is a hydrogen ion (proton) donor. When dissolved in the solvent in question, these compounds lose a proton to the solution. The concentration of these protons in solution is referred to as acidity, and is measured on the pH scale.
Lewis acid:
A substance that is an electron pair receiver. In solution, free electron pairs will form bonds with the substance, either ionic or covalent. In this definition, a proton is itself an acid, rather than a part of an acid.
A key thing to note here is that, in the Bronsted-Lowrey definition, there must be a proton. That means, all Bronsted-Lowrey acids are of the form HXn→H++Xn− , showing the dissociation in solution. However, a Lewis acid needs only to have the ability to accept an electron pair, which means that H+ is a Lewis acid, instead of what makes a compound an acid. Additionally, that means that the number of compounds that qualify as a Lewis acid are expanded. A favorite example of mine is boron trifluoride, or BF3 . It is a common reagent in organic synthesis, it is a Lewis acid, but does not have any hydrogen, so it cannot be a Bronsted-Lowrey acid
