Answer:
C I belive
Explanation:
The higher lattice energy in option a is for LiF. Similarly, MgS have higher lattice energy that NaCl and MgO have higher lattice energy than RbI.
What is lattice energy?Lattice energy of a compound is the energy required to convert one mole of that compound into its constituent gaseous ions. Lattice energy increases as the size of the ion decreases. As well as, higher the charge of the ions higher will be the lattice energy.
In LiF and KBr, Li and F are the smaller ions and is having higher lattice energy. In the case of NaCl and MgS, Mg and S are having +2 charge and are smaller causes MgO higher in lattice energy.
Similarly in the case of MgO and RbI the same concept can be applied. Rb⁺ and I⁻ are bigger ions where as Mg²⁺ and O²⁻ are comparatively smaller and have higher charge result in higher lattice energy.
Thus compound which have higher lattice energy in option a is LiF, in option b is MgS and in option C is MgO.
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Sweat is made up of all EXCEPT what?
*
A.Sugar
B.Salt
C.Urea
D.Urine
who established the two important laws of chemical combination combination state them
Answer:
Antoine Lavoisier
1) Law of Conservation of Mass
French chemist, Antoine Lavoisier in 1789, studied this law. This law states that “In all physical and chemical changes, the total mass of the reactants is equal to that of the products” or “Mass can neither be created nor destroyed.”
What are phytoplankton and what percentage of oxygen do they produce? (ASAP)
Answer:
They are plants also known as plankton and they produce about 80-85% of the world's oxygen.
Explanation:
1. How many Chromium atoms are found in 25.8 milligrams of Chromium?
Answer: 51.9961 g/mol, don't know if it helps :)
Explanation:
Answer:
Chromium is a steel-gray, lustrous, hard metal that takes a high polish, is fusible with difficulty, and is resistant to corrosion and tarnishing.
The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +4 and +5 are relatively rare. Chromium compounds of oxidation state 6 are powerful oxidants.ion:
Cells pump definition
Answer:
Pumps also called transporters, are transmembrane proteins that actively move ions and/or solutes against a concentration or electrochemical gradient across biological membranes.
what causes convection currents in a gas or liquid?
Answer:
Convection currents are caused by a temperature difference in gases and liquids. As one area becomes warmer than another the molecules have more energy and start vibrating more vigorously thus spreading out and becoming less dense. This means that the less dense parts will become more buoyant causing them to rise.
Explanation:
Answer:
Convection currents are caused by a temperature difference in gases and liquids.
Explanation:
As one area becomes warmer than another the molecules have more energy and start vibrating more vigorously thus spreading out and becoming less dense. This means that the less dense parts will become more buoyant causing them to rise.
how many moles of ethanol C2H6O, are in a 10.0g sample
Answer: 0.217 mol
Explanation:
To find the amount of moles in a 10 g sample, we need the molar mass of ethanol.
Molar Mass: 46.07 g/mol
Now that we have the molar mass, we can find moles.
[tex]10.0 g*\frac{1mol}{46.07g}=0.217 mol[/tex]
We know that there are 0.217 mol in a 10.0 gram sample.
ammonia is______a base
Answer:
Ammonia is moderately a base
How much water must be added to 424 mL of 0.189 M HCl to produce a 0.140 M solution?
Answer:
Volume of water added = 148.4 mL
Explanation:
Given data:
Initial volume = 424 mL
Initial molarity = 0.189 M
Final molarity = 0.140 M
Volume of water added = ?
Solution:
Formula:
M₁V₁ = M₂V₂
0.189 M×424 mL = 0.140 M×V₂
V₂ = 0.189 M×424 mL /0.140 M
V₂ = 80.136 M.mL / 0.140 M
V₂ = 572.4 mL
Final volume of solution is 572.4 mL.
Volume of water added = Final volume - initial volume
Volume of water added = 572.4 mL - 424 mL
Volume of water added = 148.4 mL
Match Term Definition
Pure substance A) Liquid homogeneous mixture in which the solute is distributed evenly within the solvent
Heterogeneous B) Mixture that has its different components mixed evenly within the substance
Homogeneous C) Mixture that has its different components mixed unevenly within the substance
Solution D) Consists of a single element or type of compound
Answer:
b
Explanation:
this should help
2. Enumerate four Reactive Oxygen Species (ROS)
Answer:
Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
How does the density and distribution of your “stars” change as the balloon expands?
Answer:
The Universe is constantly expanding and as it expands the stars and objects in space move farther apart, just like the points on the balloon when air is blown into it. Density and distribution of "stars" as the balloon expands because when volume increases the density will increase.
Hope this Helps
PLS HELP 35 POINTS I WILL GIVE BRAINEST
Answer:
Just count all the different elements like what elemets are in there and you have to identify the number of elemenst
Explanation:
for example H20 and a chemical for example thats two so you identofy which elelments are in there doesnt matter if thered multiple of it all its asking is what id the number of elemts there meaning like one or 2 mayne six different elements
An egg sinks in fresh water but it floats on salty water.why?
0.1400 mole of sucrose, C12H22O11, contains ________ moles of C.
can you show me the formula and the correct format
Answer:
it has 12 carbon atoms and 22 hydrogen atoms and 11 oxygen atoms
Explanation:
Which statement best describes why a chemical property change is different from a physical change?
A. A chemical change results in a different state of matter; and a physical change results in a new substance being formed.
B. A chemical change results in a new substance being formed; whereas, a physical change will result in a different state of matter.
C. A chemical change is used by scientists to create new substances, and a physical change happens naturally.
D. A chemical change is used to identify characteristics of a substance, and a physical change identifies the behavior of a substance when in a reaction.
Answer:
B
Explanation:
a chemical change is making a new substance and physical change with a result in a different state of matter:)
Which of the following grouping contains only representative elements?
A. Na, Co, S
B. Ni, Ga, Zn
c. AI, Mg, LÍ
D. CI, O, Cd
Answer:
C
Explanation:
Al=Aluminum
Mg=Magnesium
How are changes of state different from chemical change?
Question:
How are changes of state different from chemical change?
Answer:
Physical changes alter only the size, shape, form or matter state of a material. Water boiling, melting ice, tearing paper, freezing water and crushing a can are all examples of physical changes.
On the other hand, chemical changes are a bit different. In a chemical change, a new substance is formed.
Answer:
Chemical change happens when a substance changes they molecular structure, it often involves change in color (rusting iron), transfer of energy (copper smelting), or gas bubbling.
Changes of state is a physical change. An example is ice, it melts to create water. Water then can be freezed back to ice. Water is still H2O in both states（solid/liquid) Dissovling is another example. You can dissolve salt in water and can separate it by evaporating water and leaving the salt behind.
Explanation:
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Question 10 of 12- POS
GR8 Sci U03 USA FY21 Question: 1-10
Hannah added a silvery white metal to a beaker of cold water and noticed that gas bubbles were given off and a different substance formed. When she repeated the activity with hot water she noticed the gas bubbles were
released much more rapidly. Which statement best explains why the reaction occurred faster in hot water?
M
The correct answer is Hot water increases the collision rate of molecules, causing the reaction to occur faster.
Explanation:
Temperature is directly related to the kinetic energy or movement of molecules in a substance. In this context, a higher temperature leads to more kinetic energy or more collision between molecules. At the same time, a chemical reaction involves molecules of two or more substances colliding and creating bonds to form new substances. This implies an increase in temperature means molecules colliding faster, new substances forming in a shorter time, and therefore a faster chemical reaction. According to this, the first answer is correct.
Identify at least 5 pure substance found in nature,in the supermarket, grocery storeand even at your home.use the table below to explain your answer based on appearance, separating technique, boiling and melting point.
Answer:
Explanation:
1) Pure substance: Water (found at home)
Appearance: It is homogeneous since it is a single substance that appears as liquid. Homogeneous is when the components of a substance are in a single phase
Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 100 °C
Melting point: Water melts/freezes at 0°C
2) Pure substance: Table salt (found at home)
Appearance: It is also homogeneous as it is a single substance that is solid. Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 1,465 °C
Melting point: Water melts/freezes at 801 °C
3) Pure substance: Butter (found at home and grocery store)
Appearance: It is homogeneous even though it contains different components
Separating technique: It's component can be separated by physical means since butter is an emulsion of fat in water. The 15% water content can be evaporated/distilled out at 100 °C
Boiling point: Butter starts boiling at about 110-120 °C
Melting point: It melts at about 37 °C
4) Pure substance: Candle (wax) (found at home and grocery store)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 370 °C
Melting point: It melts at about 37 °C
5) Pure substance: table sugar/sucrose (found at home, grocery stores and in supermarkets)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 697 °C
Melting point: It melts at about 186 °C
A pure substance is an homogeneous material, having a composition, and
properties that are consistent through out the material.
The chemical properties of a pure substance are defined, such as the
products of its reaction can be predictable.
A chemical is pure when it consist of a single type of particle such as an
element, a molecule or a compound.
The five pure substances are presented as follows;
[tex]\displaystyle\begin{tabular}{|l|l|l|l|l|}\underline{Pure \ Substances}&\underline{Appearance}&\underline{Separaing Tech}&\underline{Boiling \ Point}&\underline{Melting \ point}\\1. Diamond&Translucent \ solid&Inseparable&3550^{\circ}&4830^{\circ}\\2. Table \ salt&White\ crystals&Insepble&801^{\circ}&1413^{\circ}\\3. Water&Tran parent \ liquid&Insepble&0^{\circ}&100^{\circ}\\4. Sugar&Whilte \ crystals&Heating&Decomposes&186^{\circ}\\5. Gold&Yellowish \ metal&Inseparable& 2700^{\circ}&1064^{\circ}\end{array}[/tex]
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How many moles of NaCl , if mixed with excess Pb2+ ions in solution, would be needed to form 45.5 g of PbCl2 ?
The number of mole of NaCl needed to react with excess Pb²⁺ to produce 45.5 g of PbCl₂ is 0.328 mole
We'll begin by calculating the number of mole in 45.5 g of PbCl₂. This can be obtained as follow:
Mass of PbCl₂ = 45.5 g
Molar mass of PbCl₂ = 207 + (35.5×2) = 278 g/mol
Mole of PbCl₂ =?Mole = mass / molar mass
Mole of PbCl₂ = 45.5 / 278
Mole of PbCl₂ = 0.164 mole Finally, we shall determine the number of mole of NaCl needed to produce 0.164 mole (i.e 45.5 g) of PbCl₂. This can be obtained as follow:2NaCl + Pb²⁺ —> PbCl₂ + 2Na⁺
From the balanced equation above,
2 moles of NaCl reacted to produce 1 mole of PbCl₂
Therefore,
Xmol of NaCl will react to produce 0.164 mole of PbCl₂ i.e
Xmol of NaCl = 2 × 0.164
Xmol of NaCl = 0.328 mole
Thus, the number of mole of NaCl needed for the reaction is 0.328 mole
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Determine the density of CO2 gas at STP
Answer:
the density of CO2 gas at STP is 1.96 g/l.
Calculate the number of S atoms in 0.670 mole of S.
Answer:
4.03 × 10²³ atomsExplanation:
The number of S atoms can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 0.67 × 6.02 × 10²³
We have the final answer as
4.03 × 10²³ atomsHope this helps you
At the Sparta Fault in Greece, the hanging wall is below the footwall. This type of fault is called a .
Answer:
1 a
Explanation:
2. Molecular solutions do not conduct electricity because they contain: *
(1 Point)
The ions are able to move freely from one place to another. So that they conduct electricity. But the molecular solutions does not electricity.
What is a molecular solution?The molecular solution is composed of molecules and consists of non - metallic atoms. These atoms are held together by the covalent bonds. The flow of charged particles is responsible for the conduction of electricity. If there is no flow of electrons or ions then there will be no electricity.
In the molecular solutions, the molecules present are not dissociated into respective ions. Since the molecules are not converted into the charged particles no electricity is produced.
A molecular solution is regarded as a non-electrolyte which does not contain ions. But electrolytes are dissociated into ions and thereby conducts electricity. So all electrolytes are good conductors of electricity.
Thus molecular solution does not contain ions.
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Explain your thoughts on whether or not using solely IR is a good method to make positive IDs of chemicals.
Answer:
No, IR should not soely be used to identify molecules
Explanation:
IR is a method that identifies the functional groups in a molecule by deducing the frequency of stretching and vibration of bonds. Each peculiar type of bond has a frequency for the vibration of each bond represented on the IR spectrum.
However, one method is never enough to identify a compound. A combination of methods must always be used to clear up ambiguities arising from overlapping IR frequencies. Also, interpretation of the nuanced peaks of the fingerprint region in IR spectra is quite challenging and only gives a fair idea of the functional groups present in the compound.
Therefore other methods such as NMR, UV-VISIBLE etc should also be involved in the identification of compounds.
PLEASE HURRY WILL GIVE BRAINLEST IF ANSWERED CORRECTLY
which separation method would be most successful in separating the components of a homogeneous mixture
screening
evaporation
centrifugation
magnetic separation
Answer:
Evaporation is a technique used to separate out homogeneous mixtures where there is one or more dissolved salts.
Explanation:
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an electric current causes water to be transformed into hydrogen and oxygen gasses a physical change or a chemical change
What are the starting substances (molecules) in a chemical equation called?
Answer:
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.
A gas sample in a balloon contains 4.0 moles of gas at a particular pressure, volume and temperature. If your balloon springs a leak and the volume decreases to 1/2 of the original amount before you can plug the leak, how many moles of gas have you lost (temperature and pressure remain the same)?
Answer:
Explanation:
When volume of gas is V , pressure is P and temperature is T , if n be number of moles of gas
PV / RT = n , R is universal gas constant .
When volume becomes .5 V , pressure P and temperature T
number of moles = Px .5 V / RT = .5 PV / RT = .5 n
Number of moles of gas becomes half .
so 4 moles becomes 2 moles
No of moles lost = 4 - 2 = 2 moles.