Answer:
true
Explanation:
the clear lens over the eye is called the cornea
How many MOLECULES are in 5.0 grams of sodium chloride? (Use "molecules" as your unit...Enter as 9.9 x 10^99 molecules)
Answer:
[tex]\boxed {\boxed {\sf 5.2 *10^{22} \ molecules \ NaCl}}[/tex]
Explanation:
1. Convert grams to moles
First, convert grams to moles using the molar mass. This can be found on the Periodic Table.
Na: 22.9897693 g/molCl: 35.45 g/molSodium (Na) has an oxidation state of +1 and chlorine (Cl) has an oxidation state of -1, so they combine in a 1:1 ratio for a formula of NaCl. We can simply add their moles masses.
NaCl: 22.9897693 g/mol + 35.45 g/mol = 58.4397693 g/molUse this as a ratio.
[tex]\frac {58.4397693 \ g \ NaCl}{ 1 \ mol \ NaCl}[/tex]
Multiply by the given number of grams.
[tex]5.0 \ g \ NaCl *\frac {58.4397693 \ g \ NaCl}{ 1 \ mol \ NaCl}[/tex]
Flip the fraction so the grams of sodium chloride cancel.
[tex]5.0 \ g \ NaCl *\frac {1 \ mol \ NaCl}{ 58.4397693 \ g \ NaCl}[/tex]
[tex]5.0 *\frac {1 \ mol \ NaCl}{ 58.4397693 }=\frac {5.0 \ mol \ NaCl} { 58.4397693 } = 0.0855581749 \ mol \ NaCl[/tex]
2. Convert moles to molecules
We must use Avogadro's Number. This tells us the amount of particles (molecules, atoms, etc.) in 1 mole of a substance. In this case, it is molecules of sodium chloride.
[tex]\frac{6.022*10^{23} \ molecules \ NaCl} {1 \ mol \ NaCl}[/tex]
Multiply by the number of moles we calculated.
[tex]0.0855581749 \ mol \ NaCl*\frac{6.022*10^{23} \ molecules \ NaCl} {1 \ mol \ NaCl}[/tex]
The moles of sodium chloride cancel.
[tex]0.0855581749 *\frac{6.022*10^{23} \ molecules \ NaCl}{1}=5.15231329*10^{22} \ molecules \ NaCl[/tex]
The original measurement of grams has 2 (2 and 0) significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place. The 5 in the hundredth place tells us to round the 1 to a 2.
[tex]5.2 *10^{22} \ molecules \ NaCl[/tex]
The close packing of particles in solids results in
Answer:
Close packing in crystals refers to space efficient arrangement of constituent particles in a crystal lattice. To understand this packing more clearly we have to assume all particles (atoms, molecules and ions) are of the same spherical solid shape. So the unit cell of a lattice is a cubic shape.
Explanation:
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Sound waves vibrate your eardrum, which moves bones in your middle
ear. The soundwaves then pass through a fluid in your inner ear, and on to
tiny hairs that send signals to the brain.
A. True
B. False
Answer: A. True
Explanation:
What is the meaning of ground state energy?
hope it helps you ❣❣
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The process of shedding an outgrown exoskeleton.
Answer:
Mouthing is the answer to your question
What is the pH of this solution?
Answer:
pH = 11.216.
Explanation:
Hello there!
In this case, according to the ionization of ammonia in aqueous solution:
[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]
We can set up its equilibrium expression in terms of x as the reaction extent equal to the concentration of each product at equilibrium:
[tex]Kb=\frac{[NH_4^+][OH^-]}{[NH_3]} \\\\1.80x10^{-5}=\frac{x*x}{0.150-x}[/tex]
However, since Kb<<<1 we can neglect the x on bottom and easily compute it via:
[tex]1.80x10^{-5}=\frac{x*x}{0.150}\\\\x=\sqrt{1.80x10^{-5}*0.150}=1.643x10^{-3}M[/tex]
Which is also:
[tex][OH^-]=1.643x10^{-3}M[/tex]
Thereafter we can compute the pOH first:
[tex]pOH=-log(1.643x10^{-3}M)\\\\pOH=2.784[/tex]
Finally, the pH turns out:
[tex]pH=14-2.784\\\\pH=11.216[/tex]
Regards!
What is the concentration of a strong base solution (of an alkali metal) that has a pH of 11.39?
Answer:
[tex][OH^-]=2.455x10^{-3}M[/tex]
Explanation:
Hello there!
In this case, since a strong base produce OH ions in solution, it possible to first compute the pOH as shown below:
[tex]pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-11.39\\\\pOH=2.61[/tex]
Thus, via the definition of the pOH we can compute the concentration of the strong base as follows:
[tex]pOH=-log([OH^-])[/tex]
Thus, solving for the concentration we obtain:
[tex][OH^-]=10^{-pOH}=10^{-2.61}[/tex]
[tex][OH^-]=2.455x10^{-3}M[/tex]
Best regards!
How many atoms is 3.2 mol phosphorus?
Answer:
I think 4 I'm not completely sure
Explanation:
I hope it's right
Which action is not an example of work?
A. pushing a box across the floor
B. picking up a box off the floor
C. holding a tray in the Cafeteria line
D. raising a barbell over your head
C. picking a tray in the cafeteria line
What process at the surface of the Earth is part of the formation of sedimentary rocks?
A. the cycle of day and night
B. water depositing sediment in layers
C. magma rising from the Earth's mantle
D. rain falling into the ocean
Answer:
Clastic sedimentary rocks are made up of pieces (clasts) of pre-existing rocks. Pieces of rock are loosened by weathering, then transported to some basin or depression where sediment is trapped. If the sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock.
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Suppose you are titrating an acid solution with a base solution of known concentration. To calculate the concentration of the acid solution, use three steps.
1. Use the____of base____the endpoint and the known concentration of the base solution to find the_____of base used.
2. Use the_____to find the moles of acid from the moles of base.
3. Divide the moles of acid by the volume of_____the titration to find the concentration of acid.
Answer:
To calculate the concentration of the acid solution, use three steps.
1. Use the volume of base used at the endpoint and the known concentration of the base solution to find the moles of base used.
2. Use the stoichiometry to find the moles of acid from the moles of base.
3. Divide the moles of acid by the volume of acid used in the titration to find the concentration of acid.
Explanation:
Titration is the process used in volumetric analysis to determine the amount of a substance present in a given sample.
In any titration, a solution of known concentration known as the standard solution is used to react with a solution of of unknown concentration. The reacting volumes of the solutions are then used to calculate the unknown concentration of the second solution.
In acid-base neutralization reactions, an equivalence point/endpoint of the neutralization titration is obtained and is the point at which the moles of H+ is equal to the moles of OH- . An indicator is used to indicate the equivalence point during a titration by a color change observed in the indicator.
In order to calculate the concentration of an acid, we need to know accurately, use three steps:
1. Use the volume of base used at the endpoint and the known concentration of the base solution to find the moles of base used.
2. Use the stoichiometry of the reaction to find the moles of acid from the moles of base.
3. Divide the moles of acid by the volume of acid used in the titration to find the concentration of acid.
In order to calculate the concentration of a base, use three steps:
1. Use the volume of acid used at the endpoint and the known concentration of the acid solution to find the moles of acids used.
2. Use the stoichiometry of the reaction to find the moles of base from the moles of acid.
3. Divide the moles of base by the volume of base used in the titration to find the concentration of base.
When a substance is a solid it has
A. Potential energy
B. Kinetic energy
C. Gravitational energy
D. Chemical energy
Answer:
potential energy
Explanation:
An experiment requires 66.6 g of ethyl alcohol (density = 0.790 g/mL). What is the volume?
Answer:
Volume = 84.30 mLExplanation:
Mass = 66.6 gram
Density = 0.790 g/mL
Volume = Mass ÷ Density
Volume = 66.6 ÷ 0.790
Volume = 84.30 mL
What is the total number of oxygen atoms on the left-hand side of this chemical equation?
2 Caz(PO4),(s)+48i0,(s) +12C(s) - 4 Casio2(3)+P4($)+12CO(g)
Answer:
Is the answer eight atoms
Which type of front is most likely moving through this area?
A. cold front
B. warm front
C. occluded front
D. stationary front
Answer:
Cold front
Explanation:
Determine the number of shared and unshared electrons in the structure. shared (bonding) electrons: unshared (lone, nonbonding) electrons: Determine the number of shared and unshared pairs of electrons in the structure. shared (bonding) pairs of electrons: unshared (lone, nonbonding) pairs of electro
Answer:
Shared (bonding) electrons : 8
Unshared (lone, non-bonding) electrons : 16
Explanation:
The Lewis dot stricture of the molecule attached to this answer shows us all the valence electrons present in the molecule.
Altogether, we have a total number of 24 valence electrons in SO3.
There are eight electrons shared between atoms of elements, these are the bonding electrons.
There are sixteen electrons that are not shared between atoms of elements, These are the lone or non-bonding electrons.
Hence, there are four shared pairs of electrons and eight pairs of unshared electrons.
Help me answer this please
Are the electrons in the following redox reactions transferred completely from the atoms of one element to the atoms of another or are they only partially transferred?
a. Ca(s) + Cl2(g) → CaCl2(s)
b. 4Cu(s) + O2(g) → 2Cu2O(s)
The electrons, in redox reaction get partially transferred by one to another element.
What is redox reaction?A redox reaction occurs when the oxidation states of the substrate change. The loss of electrons or maybe an increase in the oxidation state of a chemical and its atoms is referred to as oxidation. The gain of electrons or a reduction in the oxidation state of either a chemical or its atoms is referred to as reduction. The oxidation as well as reduction process can be seen in same reaction which is introduced as redox reaction.
What is electrons?
Electron can be considered as sub atomic particle which carry negative charge on it.
The given reactions are:
a. Ca(s) + Cl2(g) → CaCl2(s)
b. 4Cu(s) + O2(g) → 2Cu2O(s)
After transferring two electron in both reaction Ca and Cu it will form CaCl2 and 2Cu2O.
Therefore, after transferring partially electrons one elements get converted into another kind of molecule
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At point a the object has 30 joules of energy. how much energy does the object have at point b?
Answer:
It’s 10
Explanation:
I looked it up
To solve this we must be knowing each and every concept related to energy and its calculations. Therefore, at point b, 10joule of energy is present.
What is energy?Energy is defined in physics as the ability to accomplish work or heat items. It's a scalar measurement with magnitude but no direction. Energy is maintained, which implies it can change forms but is not generated or destroyed. potential energy transforms into kinetic energy.
One type of energy can be transferred into another without breaking a thermodynamic rule. Not all of these energy sources are equally beneficial in practical applications. At point a the object has 30 joules of energy. At point b, 10joule of energy is present.
Therefore, at point b, 10joule of energy is present.
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An earthquake creates a type of wave that shakes the ground. If a large earthquake occurs in Greece, how can the waves be felt across the sea in Italy?
A.
Waves can be transformed into strong winds that travel across the sea.
B.
Waves do not travel through water, but they can crash the sea into land far away.
C.
Waves can cause a series of earthquakes around the world.
D.
Waves can travel through different media including solid land and water.
The element with the symbol Na
Select one
Cell
Metalloid
Non metal
Metal
Answer:
metal
Explanation:
it's a soft silvery metal
A sample of a gas at 25°C has a volume of 150 mL when its pressure is 0.947 atm. What will the temperature of the gas be at a pressure of 0.987 atm and changes to 144mL?
*please help*
Answer:
25°C
Explanation:
Combined Gas Law (P₁V₁)/T₁ = (P₂V₂)/T₂
(0.947 atm)(150 mL)/25°C = (0.987 atm)(144mL)/T₂
5.682 = 142.128/T₂
T₂ = 142.128/5.682
T₂ = 25.0137272756°C = 25°C
Calculate the pH of the buffer solution comprised of 0.20 M HCHO2 and 0.15 M NaCHO2. (Ka for HCHO2 = 1.8 x 10-4)
Answer:
3.62
Explanation:
Using the Henderson-Hasselbach equation:
pH = pKa + log[base]/[acid]
pH = -log(1.8 x 10^-4) + log(0.15/0.20) = 3.62
The pH of acid is between 0-7 on pH scale while for base pH range is from 7-14. Therefore, the pH of of the buffer solution comprised of 0.20 M HCHO₂ and 0.15 M NaCHO₂. (Ka for HCHO2 = 1.8 x 10⁻⁴) is 3.62. pH is a unitless quantity.
What is pH?pH is a measurement of amount of hydronium ion H₃O⁺ in a given sample. More the value of hydronium ion concentration, more will be the solution acidic.
On subtracting pH from 14, we get pOH which measures the concentration of hydroxide ion in a given solution. pH depend on the temperature. At room temperature pH scale is between 0 to 14. pH of neutral solution is 7.
Using the Henderson-Hassel Bach equation:
pH = pKa + log[base]/[acid]
pH = -log(1.8 x 10^-4) + log(0.15/0.20) = 3.62
Therefore, the pH of of the buffer solution comprised of 0.20 M HCHO2 and 0.15 M NaCHO2. (Ka for HCHO2 = 1.8 x 10-4) is 3.62.
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Balance the following equations.
Al4C3 + H2O → Al(OH)3 + CH4
NH3 + O2 → NO + H2O
Answer:
Al4C3 +12 H2O → 4Al(OH)3 + 3CH4
4NH3 + 5O2 → 4NO + 6H2O
What process is represented by the letter on the diagram?
A: ____________________________________________
B: ____________________________________________
C: ____________________________________________
D: ____________________________________________
E: ____________________________________________
Explanation:
I don't really understand the question
9. Which of the following is needed as a reactant for cellular
respiration?
A. Carbon dioxide
B. Oxygen
C. Water
D. Chlorophyll
oxygen is needed as a reactant for cellular respiration
What is cellular respiration ?
Cellular respiration can be defined as the process which occurs in every cells mainly mitochondria of plants and animals, it involve in the break down of sugars in the presence of oxygen and releases energy in the form of ATP.
The waste product of this process are carbon dioxide and water during exhalation process done by lungs, breathing and cellular respiration are related to each other.
At every step of cellular respiration energy is used in the form of ATP and carry out the normal function. It can aerobic and anaerobic respiration on the basis of use of oxygen.
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How could a solid result from the mixing of two liquids?
Answer:
Combining the two clear colorless liquids is a chemical change because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically. Insoluble means that the solid will not dissolve.
Explanation:
If 85.6 grams of water are produced by the reaction then how many grams of calcium hydroxide did you start with?
Answer:
I think it would double it's self
Draw a line to connect the following terms to their definition.
In a circuit that has a total current of 4 amps with 4 lightbulbs wired in parallel, what is the current at each bulb?
Answer: 1 A for each lamps
Explanation: we assume lamps are similar and lamps have same resistance.
Then current is divided according Kirchhoff s law equally to all lamps.
An aqueous solution containing 6.06 g of lead(II) nitrate is added to an aqueous solution containing 6.58 g of potassium chloride. Enter the balanced chemical equation for this reaction. Be sure to include all physical states. balanced chemical equation: What is the limiting reactant
Answer:
Pb(NO₃)₂ is the limiting reactant.
The equation is: Pb(NO₃)₂ (aq) + 2KCl (aq) → PbCl₂ (s) ↓ + 2KNO₃ (aq)
Explanation:
We identify our reactants:
Pb(NO₃)₂ → Lead (II) nitrate
KCl → Potassium chloride
Our reaction is:
Pb(NO₃)₂ (aq) + 2KCl (aq) → PbCl₂ (s) ↓ + 2KNO₃ (aq)
1 mol of Lead (II) nitrate reacts to 2 moles of KCl, in order to produce 2 moles of potassium nitrate and 1 mol of slid Lead (II) chloride.
We determine the moles of the reactants:
6.06 g . 1mol /331.2 g = 0.0183 moles of Lead (II) nitrate
6.58 g . 1mol / 74.55g = 0.0882 moles of KCl
2 moles of KCl react to 1 mol of Pb(NO₃)₂
Then, 0.0882 moles of KCl may react to (0.0882 . 1) /2 = 0.0441 moles
We have 0.0183 moles of Pb(NO₃)₂ and we need 0.441 moles. Then, the
Pb(NO₃)₂ is our limiting reactant.