A 25.0 ml sample of 0.105 m hcl was titrated with 31.5 ml of naoh. what is the concentration of the naoh?

Answers

Answer 1
the balanced equation for the above reaction is 
NaOH + HCl ---> NaCl + H₂O
stoichiometry of NaOH to HCk is 11:
number of HCl moles reacted - 0.105 mol/L x 0.0250 L = 0.00263 mol
according to molar ratio, number of HCl moles = number of NaOH moles 
therefore number of NaOH moles - 0.00263 mol
number of moles in 31.5 mL - 0.00263 mol
therefore number of NaOH moles in 1000 mL = 0.00263 / 31,5 mL x 1000 mL
molarity of NaOH - 0.0835 M
Answer 2

The concentration of the NaOH: 0.083 M

Further explanation

Titration is a procedure for determining the concentration of a solution by reacting with another solution which is known to be concentrated (usually a standard solution). Determination of the endpoint / equivalence point of the reaction can use indicators according to the appropriate pH range

Titrations can be distinguished including acid-base titration, depositional titration, and redox titration. An acid-base titration is the principle of neutralization of acids and bases is used.

An acid-base titration there will be a change in the pH of the solution.

From this pH change a Titration Curve can be made which is a function of acid / base volume and pH of the solution

Acid-base titration formula

Ma Va. na = Mb. Vb. nb

Ma, Mb = acid base concentration

Va, Vb = acid base volume

na, nb = acid base valence

Neutralization Reaction:

NaOH + HCl ⇒ NaCl + H₂O

25.0 ml, 0.105 M HCl was titrated with 31.5 ml of NaOH

Acid-base titration formula

Ma Va. na = Mb. Vb. nb

a = HCl, b = NaOH (both have valence 1)

0.105 M. 25 = Mb. 31.5. 1

[tex]\rm Mb = \dfrac {0.105 \times 25} {31.5} \\\\ Mb = \boxed {\bold {0.083 \: M}}[/tex]

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Related Questions

The acid dissociation constant for an acid dissolved in water is equal to the ____.
a. equilibrium constant
b. equilibrium constant times the concentration of water
c. equilibrium constant divided by the concentration of water
d. equilibrium constant times the equilibrium constant of water

Answers

equilibrium constant times the concentration of water. - 100% guaranteed correct

Answer:The correct answer is option b.

Explanation:

[tex]HA+H_2O\rightleftharpoons A^-+H_20^+[/tex]

The equilibrium constant expression is given as:

[tex]K_{eq}=\frac{[A^-][H_3O^+]}{[HA][H_2O]}[/tex]

[tex]K_a=K_{eq}\times [H_2O]=\frac{[A^-][H_3O^+]}{[HA]}[/tex]

The acid dissociation constant is product of equilibrium constant and concentration of water.

Hence,from the given options the correct answer is option b.

A chef is going to use a mixture of two brands of italian dressing. the first brand contains 7% vinegar, and the second brand contains 11% vinegar. the chef wants to make 240 milliliters of a dressing that is 8% vinegar. how much of each brand should she use?

Answers

Answer is: 180 mL of 7% vinegar and 60 mL of 11% vinegar.

ω₁ = 7% ÷ 100% = 0.07.
ω₂ = 11% ÷ 100% = 0.11.
ω₃ = 8% ÷ 100% = 0.08.
V₁ = ?.

V₂ = ?.
V₃ = V₁ + V₂.
V₃ = 240 mL.

V₁ = 240 mL - V₂.
ω₁ · V₁ + ω₂ ·V₂ = ω₃ · V₃.

0.07 · (240 mL - V₂) + 0.11 · V₂ = 0.08 · 240 mL.

16.8 mL - 0.07V₂ + 0.11V₂ = 19.2 mL.

0.04V₂ = 2.4 mL.

V₂ = 2.4 mL ÷ 0.04.

V₂ = 60 mL.

V₁ = 240 mL - 60 mL.

V₁ = 180 mL.

Explain how solid naphthalene in mothballs is distributed evenly through clothes in a drawer

Answers

It's a vapor that penetrates fibers. Don't let their appearance fool you.

How many grams of lead (ii) chloride will dissolve in a 0.750 l of 0.650 m pb(no3)2 solution? the ksp of lead (ii) chloride is 1.7 x 10-5 ?

Answers

if you do it is 2130 

A "fizz saver" pumps air under pressure into a soda bottle to keep gas from escaping. will this keep co2 in the soda bottle? explain your answer.

Answers

A fizz saver forms an airtight seal around the now-upsidedown soda bottle, and the pressure exerted by the drink and the atmospere outside pushes out the drink through the slightly-elevated spout. The CO2 gas does not fizz out because it stays at the bottom of the upside-down bottle. Thus the CO2 gas is trapped and the drink is carbonated at a longer time.

Answer:

yeah...what he/she said...lol

Explanation: I was going to say that anyways.....btw am i the only one who has a problem with chemistry right now??? I need a tutor right about now....like baddddd!!!!

How many grams of calcium chloride are needed to produce 1.50 g of potassium chloride? cacl2(aq) + k2co3(aq) → 2 kcl(aq) + caco3(aq) 1.12 g 2.23 g 0.896 g 4.47 g?

Answers

The calcium chloride needed to produce 1.5 grams of KCl is: 1.12 grams

Further explanation

Stoichiometry in Chemistry learn about chemicals mainly emphasizes quantitative, such as the calculation of volume, mass, number, which is related to numbers, molecules, elements, etc.

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

In the reaction there are also manifestations of reagent substances namely gas (g), liquid (liquid / l), solid (solid / s) and solution (aqueous / aq).

Reactions that occur:

CaCl₂ (aq) + K₂CO₃ (aq) → 2 KCl (aq) + CaCO₃ (aq)

From the reaction equation above, the reaction coefficient shows the mole ratio of reagents and products

mol CaCl₂: moles of KCl = 1: 2

relative molecular mass KCl = 74.6

relative molecular mass of CaCl2 = 111

then the mole:

mole KCl = mass: relative molecular mass

mole KCl = 1.5 gram: 74.6

mole KCl = 0.020107

so that

mole CaCl₂ = 1/2. 0.020107

mole CaCl₂ = 0.0100535

So the mass of CaCl2 = mole x relative molecular mass

mass CaCl₂ = 0.0100535 x 111

mass CaCl₂ = 1.12 gram

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Keywords: CaCl2, KCl, mole, mass, relative molecular mass

The mass calcium chloride needed is 1.12 g

The balanced equation for the reaction is illustrated below:

CaCl₂ + K₂CO₃ —> 2KCl + CaCO₃

Next, we shall determine the mass of CaCl₂ that reacted and the mass of KCl produced from the balanced equation.

Molar mass of CaCl₂ = 40 + (35.5×2)

= 40 + 71

= 111 g/mol

Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g

Molar mass of KCl = 39 + 35.5

= 74.5 g/mol

Mass of KCl from the balanced equation = 2 × 74.5 = 149 g

Thus,

From the balanced equation above,

111 g of CaCl₂ reacted to produce 149 g of KCl.

Finally, we shall determine the mass of CaCl₂ needed to produce 1.5 g of KCl as follow:

From the balanced equation above,

111 g of CaCl₂ reacted to produce 149 g of KCl.

Therefore, X g of CaCl₂ will react to produce 1.5 g of KCl i.e

X g of CaCl₂ = [tex]\frac{1.5 * 111}{149}[/tex]X g of CaCl₂ = 1.12 g

Thus, 1.12 g of calcium chloride, CaCl₂ is needed to produce 1.5 g of KCl.

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Write the equation for the dissolution of sr(no3)2 in water. how many moles of strontium ions and nitrate ions are produced by dissolving 0.5 mol of strontium nitrate?

Answers

                                    Sr(NO3)2 ---> Sr²⁺ +       2 NO3⁻
from the reaction         1 mol            1 mol           2 mol
from the problem         0.5 mol         0.5 mol        1 mol

Answer: Moles of strontium and nitrate ions formed by dissolving 0.5 moles of strontium nitrate in water are 0.5 moles and 1 mole respectively.

Explanation:

We are given a chemical compound known as strontium nitrate having chemical formula [tex]Sr(NO_3)_2[/tex]. This is an ionic compound and when it is dissolved in water, it will dissociate into its respective ions.

We are given:

Moles of strontium nitrate = 0.5 moles

The chemical equation for the ionization of strontium nitrate follows:

[tex]Sr(NO_3)_2(aq.)\rightarrow Sr^{2+}(aq.)+2NO_3^-(aq.)[/tex]

By Stoichiometry of reaction:

1 mole of strontium nitrate produces 1 mole of strontium ions and 2 moles of nitrate ions.

So, 0.5 moles of strontium nitrate will produce = [tex](1\times 0.5)=0.5mol[/tex] of strontium ions and [tex](2\times 0.5)=1mol[/tex] of nitrate ions.

Hence, moles of strontium and nitrate ions formed by dissolving 0.5 moles of strontium nitrate in water are 0.5 moles and 1 mole respectively.

What is the celsius temperature of 100.0 g of chlorine gas in a 55.0-l container at 800 mm hg?

Answers

Given, pressure = P = 800 mm Hg = 1.066 X 10^5 Pa
Volume = V = 55 l = 0.055 m^3
number of moles of Cl2 gas = n = [tex] \frac{weight}{\text{molecular weight}} [/tex] = [tex] \frac{100}{71} [/tex] = 1.408

Now, based on ideal gas equation, we have
PV=nRT
∴ T = PV/RT
where R = universal gas constant = 8.314 J /mol K
∴ T = [tex] \frac{1.066X 10^5X0.055}{1.408X8.314} [/tex] = 500.8 K

Now, we know that [tex] 0^{0}C = 273.15 K [/tex]
∴ 500.8 K = [tex] 227.65^{0}C [/tex]
Final answer:

To calculate temperature of a gas, use the ideal gas law PV=nRT. Substitute the given values, including the number of moles calculated from the mass and molar mass of chlorine, and solve for the temperature. The result will be in Kelvin, so convert to Celsius.

Explanation:

The celsius temperature of 100.0 g of chlorine gas in a 55.0-l container at 800 mm hg can be calculated by using the ideal gas law: PV = nRT. Here, P = Pressure = 800 mm hg (we must convert this to atmospheres by using the conversion factor 1 atm = 760 mm hg), V = volume = 55.0 liters, n = number of moles (which we can calculate by using chlorine's molar mass), R = ideal gas constant = 0.08206 L.atm/(mol.K), T = temperature (which is what we're solving for). After substitifying and calculating values, the final temperature would be expressed in Kelvin, which could be easily converted to Celsius by subtracting 273.15.

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When calcium carbonate is heated strongly, it forms calcium oxide and carbon dioxide. what mass of calcium carbonate is needed to make 50.0 g of calcium oxide?

Answers

The mass is 34 g needed

To produce 50.0 g of calcium oxide, 89.29 g of calcium carbonate is required. The amount is calculated based on the fixed ratio of the decomposition reaction of calcium carbonate, which aligns with the law of conservation of mass.

To determine the mass of calcium carbonate ([tex]CaCO_3[/tex]) needed to produce 50.0 g of calcium oxide (CaO), it's essential to refer to the stoichiometry of the chemical reaction. The balanced chemical equation for the decomposition of calcium carbonate is:

[tex]CaCO_3(s) \rightarrow CaO(s) + CO_2(g)[/tex]

From the given examples, we can deduce that when 10.0 g of calcium carbonate decompose, they produce 5.6 g of calcium oxide. This means there is a fixed ratio of mass of calcium carbonate to calcium oxide, which is:

Mass of CaCO3 : Mass of CaO = 10.0 g : 5.6 g

To produce 50.0 g of calcium oxide, we can set up a proportion based on the fixed ratio:

10.0 g CaCO3 / 5.6 g CaO = x g CaCO3 / 50.0 g CaO

By solving for x, which represents the mass of calcium carbonate needed, we can cross-multiply and divide to find the answer:

[tex]x = (10.0 g CaCO3 \times 50.0 g CaO) / 5.6 g CaO[/tex]

x = 89.29 g of CaCO3

Therefore, to obtain 50.0 g of calcium oxide, you would need 89.29 g of calcium carbonate. This calculation is in agreement with the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction.

How many moles in 43 liters of co2 at stp?

Answers

Let's assume that CO₂ has ideal gas behavior.

Then we can use ideal gas formula to solve this.
PV = nRT

Where,
   P = Pressure of the gas (Pa)
   V = Volume of the gas (m³)
   n = moles of the gas (mol)
  R = Universal gas constant (8.314 J K⁻¹ mol⁻¹)
  T = Temperature in Kelvin (K)

In this problem,
  P = Standard pressure = 1 atm = 101325 Pa
  V = 43 L = 43 x 10⁻³ m³
  R = 8.314 J K⁻¹ mol⁻¹
  T = standard temperature = 273 K
  n = ?

     PV = nRT
By rearranging,
       n = PV / RT
       n = (101325 Pa x 43 x 10⁻³ m³) / (8.314 J K⁻¹ mol⁻¹ x 273 K)
       n = 1.92 mol

Hence moles of CO₂ gas in 43 L at STP = 1.92 mol

Answer: wait im gonna search some info.

Explanation:I come back with an asnwer for you

Why did the Tacoma Narrows Bridge Collapses

Answers

As a result of aeroelastic flutter caused by a 42 mph wind.

Final answer:

The Tacoma Narrows Bridge collapsed due to resonance caused by heavy crosswinds and insufficient damping. The bridge's design did not consider these factors, leading to its failure.

Explanation:

The catastrophic collapse of the Tacoma Narrows Bridge stands as a poignant reminder of the critical importance of comprehensive engineering considerations. The unfortunate event was precipitated by intense crosswinds that triggered resonant oscillations within the bridge, ultimately leading to its demise. The absence of sufficient damping, exacerbated by the detachment of support cables, allowed the oscillations to escalate uncontrollably, reaching destructive amplitudes.

The failure highlighted a critical oversight in the bridge's design, as it did not incorporate adequate measures to mitigate the effects of resonance. The omission of sophisticated mathematical tools for analyzing wave dynamics and resonance in structural engineering further underscored the limitations in understanding and predicting the complex interplay of forces. This incident spurred advancements in engineering practices, emphasizing the imperative of incorporating resonance considerations and meticulous mathematical modeling to enhance the structural integrity and resilience of bridges and similar constructions. The lessons learned from the Tacoma Narrows Bridge collapse have significantly influenced subsequent infrastructure projects, contributing to the evolution of engineering practices and the development of more robust and secure structures.

Nitric acid can be produced by the reaction of gaseous nitrogen dioxide with water. 3 no2(g) + h2o(ℓ) −→ 2 hno3(ℓ) + no(g) if 854 l of no2 gas react with water, what volume of no gas will be produced? assume the gases are measured under the same conditions. answer in units of l.

Answers

the balanced equation for the above reaction is as follows;
3NO₂ + H₂O --> 2HNO₃ + NO
stoichiometry of NO₂ to NO is 3:1
molar volume is where 1 mol of any gas occupies a volume of 22.4 L
volume of gas is directly proportional to number of moles of gas.
therefore stoichiometry can be applied for volume as well.
volume ratio of NO₂ to NO is 3:1
volume of NO₂ reacted - 854 L
therefore volume of NO formed - 854 L /3 = 285 L
volume of NO formed - 285 L

Final answer:

To determine the volume of NO gas produced from 854 L of NO₂ gas reacting with water, the stoichiometry of the balanced reaction (3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)) indicates a 3:1 ratio. Using this ratio, the calculated volume of NO gas produced is 284.67 L.

Explanation:

To calculate the volume of NO gas produced when 854 L of NO₂ gas react with water, we can use the stoichiometry of the balanced chemical equation:

3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)

According to the equation, 3 moles of NO₂ produce 1 mole of NO. This ratio can be applied to the volumes of the gases involved, as they are both measured under the same conditions and thus follow the ideal gas law where volume is directly proportional to moles.

To find the volume of NO produced:

Determine the mole ratio from the chemical equation: 3 moles of NO₂ produce 1 mole of NO.

Use the mole ratio to find the volume ratio for NO₂ to NO, which is also 3:1.

Apply the volume ratio to the given volume of NO₂: 854 L of NO₂ × (1 mole NO / 3 moles NO₂) = 284.67 L of NO.

So, under the same conditions, the volume of NO gas produced would be 284.67 L.

Photosynthesis is an endothermic chemical reaction that forms sugars from carbon dioxide, water, and the sun's energy. Which of the following must be true of photosynthesis?

The reaction can take place only if energy is added.
The reactants are oxidized.
The photosynthesis reaction produces ions.
The molecular bonds in carbon dioxide are very weak.

Answers

The photosynthesis reaction produces ions

Answer: The reaction can take place only if energy is added.

Explanation:

Exothermic processes are those processes in which heat is released and endothermic processes are those processes in which heat is absorbed.

Photosynthesis is a phenomenon in which green plants containing chlorophyll use sunlight as a source of energy to convert carbon dioxide and water to form glucose and oxygen.

Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight and turn it into chemical energy in the form of glucose which is used a s a source of energy by many organisms.

[tex]6CO_2+6H_2O\overset{sunlight}\rightarrow C_6H_{12}O_6+6O_2[/tex]

Thus photosyynthesis reaction can take place only if energy is added.

After measurements or observations are made in a scientific investigation, it is most appropriate to

Answers

After observations are made, it is crucial to record and present results properly, discuss findings, and formulate hypotheses for further testing in the scientific investigation process.

After measurements or observations are made in a scientific investigation, it's most appropriate to record your observations and present your results in a suitable format, such as tables and graphs. Discussing findings with group members is also important, coupled with formulating a relevant central idea. If a scientist develops a new idea based on their observations of nature, the next step would be to make a new hypothesis, which can then be tested through experiments.

As part of the scientific method, it's essential not to force data to fit a hypothesis. Instead, draw conclusions from the experiment results objectively. If data fits, you should repeat the experiment to verify results, or if it does not, conduct more background research and refine the hypothesis.

If the reactants of a reaction have one s and four o atoms, what will the products have?

Answers

Answer:
            The products will also have one S and four O atoms.

Explanation:
                   According to Law of Conservation of Matter, " Matter can neither be created nor destroyed, but it can be changed from one form into another".
                   So, in given scenario the number of atoms in reactants and products will also remain the same, but their chemical composition can vary. They might have no similarity in chemical composition but their numbers will remain the same.
                   The reaction might be the decomposition of sulfuric acid,, 

                                        H₂SO₄     →     SO₃  +  H₂O

In above case number of S and O on both sides are same, but chemical composition has changed.

Answer:

one S four O atoms

Explanation:

If an endothermic process absorbs 256j how many kilocalories are absorbed

Answers

There are several units for expressing energy, Most common are joules and kilocalories.

The conversion factor of joule to kilocalories is 
 1 kilo calorie  = 4184 J
∴ x kilo calorie = 256 J

x = [tex] \frac{256}{4184} = 0.0611 [/tex] kilo calories

Thus, 256 J = 0.0611 kilocalories

Answer: 0.0612 kcalories

Explanation:

Endothermic processes are those processes in which heat is absorbed and exothermic processes are those processes in which heat is released.

Standard units for heat measurement are Joules and calories wherein

1 joule = 0.239 calorie.

As 1 Joule is equivalent to 0.239 calorie

256 Joules are equivalent to=[tex]\frac{0.239}{1}\times 256=61.2calories[/tex]

Now 1 cal = 0.001 kcalories

Therefore 61.2 calories=[tex]\frac{0.001}{1}\times 61.2=0.0612kcal[/tex]

HELP PLEASE!! ILL GIVE 20 POINTS :)))

1)The compound CO2 is an example of a(n) (2 points)

atom

element

ionic compound

covalent compound

2) What is another name for a compound known as a salt? (2 points)

Molecule

Covalent compound

Element

Ionic compound

Answers

1)The compound CO2 is an example of a(n) covalent compound

CO2 or carbon dioxide is made of carbon and oxygen molecules. It is a compound because it composed of two kinds or more element. Both carbon and oxygen is a gas, so the compound will form a covalent bond. The bond is not easily broken like ionic one.

2) What is another name for a compound known as a salt? Ionic compound

Salt that you mostly found in cooking is sodium chloride or NaCl. It is a compound because it composed of two kinds or more element. Natrium/sodium is metal while chlorine is gas. These compound will form ions(Na+ and Cl-) when dissolved into solution.

Which technique is used to compare ink on a suspect document?
A) thin-layer chromatography
B) infrared spectrophotometry
C) blotting with alcohol method
D) ultraviolet spectrophotometry

Answers

Final answer:

The technique of thin-layer chromatography is used to compare ink on a suspect document. This is done by creating a chromatogram through exposing the ink to a solvent and observing the resulting pattern of spots.

Explanation:

The technique used to compare ink on a suspect document is A) thin-layer chromatography. Thin-layer chromatography is a type of chromatography that is widely used to separate mixtures in forensic analysis. In this process, the ink sample from the suspect document is placed on a thin layer of absorbent material.

The sample is then exposed to a solvent, which moves up the stationary phase, carrying different components of the ink at different rates. This results in a series of spots, that form a chromatogram, can then be compared to known samples for identification.

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What might be damaged by ionizing radiation? *

lead
paper
soft tissue

Answers

Soft tissue would be damaged because the radiatio would cause mutations in the cells and it would also destroy the tissue. Lead will stop the radiation and paper will allow it to pass straight through

what is fry's reagent used for?

Answers

Fry's Reagent a chemical used on metals such as firearms, it corrodes them and allows you to see the etching that could have been scratched off by the criminal, such as the serial number of the gun.  It is a chemical that can restore a serial number that has been removed from a gun by dissolving the area that has been flattened when the number was stamped on.

Fry's reagent is a chemical tool used to detect aldehydes through a color change to bright magenta, offering a simple and fairly reliable test for the presence of these functional groups in various chemical applications.

Fry's reagent is a chemical reagent commonly used in a method to detect aldehydes. It consists of a decolorized fuchsin dye that can be activated by sulfur dioxide. When Fry's reagent comes into contact with aldehydes, it will cause a color change to bright magenta, indicating the presence of these functional groups. This method is known for its simplicity and reliability, although it is important to note that it might not always produce clear-cut results as anticipated.

Detecting aldehydes is crucial in various applications, such as confirming the presence of specific biomolecules in biochemistry or determining the purity of chemical compounds in synthetic chemistry. The color change of Fry's reagent provides a visual cue that can be quickly interpreted by researchers.

Which type of van der walls force is responsible for holding polar molecules together? london dispersion dipole-dipole hydrogen bonding gravitational force?

Answers

Answer:

dipole-dipole

Explanation:

Polar molecules are formed as result of covalent bonds between atoms.

Dipole-dipole attraction are intermolecular bonds. Both London dispersion forces and dipole-dipole attraction are van der waals forces.

In dipole-dipole attraction, polar molecules (unsymmetrical molecules) line up such that the positive pole of one molecule attracts the negative pole of another. Example of such is found in HCl.

Answer:

Dipole-dipole forces are the van der Waals forces that hold polar molecules together!!

why are you able to collect a more concentrated sample of ethanol from a mixture of water and ethanol using fractional distillation

Answers

Fractional Distillation uses the differences in boiling points to separate liquids that are hard to separate manually (like with a pipette or filtration).

Water boils at 100°C, while ethanol boils at around 78-79°C. So, if you heated the solution to 78-79°C, the ethanol would boil off and the water would stay in its liquid form. The Ethanol can be collected in a more concentrated form this way.

Hope this helps!

1. A _____ is a framework of ideas and assumptions that has been well tested and can be used to explain some set of observations and make predictions about the world
A. law
B. theory
C. ladder
D. focus
I think it is B but please help me
2. How can astronomers locate objects in the sky?
A. by using altitude and zenith
B. by using latitude and longitude
C. by using distance and compass directions
D. by using the celestial sphere and constellations
I dont have a clue with this one please help me

Answers

Yes, the first question is B. The second question is D.

1. A B. Theory is a framework of ideas and assumptions that has been well tested and can be used to explain some set of observations and make predictions about the world.

Although "theory" is a concept that is always in discussion, the scientifics agree on some points. It must be logically composed of concepts, definitions, assumptions, and generalizations. Secondly, it's major function is to describe and explain, it is important to say that a theory is a general explanation that leads to basic principles. In the third place, a theory is heuristic because it stimulates and guides to further development of knowledge.

2. How can astronomers locate objects in the sky?

D. by using the celestial sphere and constellations

Astronomers locate objects in the sky in a very simillar way we locate places in a map. Instead of using latitude and longitude, they use declination and right ascension. This is based on the celestial sphere, an imaginary object that is created by asuming all objects in space are at the same distance. By doing this astronomers can determine a line of zero latitude and zero longitude and therefore locate precisely distant objects. They can use also constelations as references with this same method.

Question 3 given that au-197 is the only natural isotope of gold, what is the mass of one au atom and the mass of avogadro's number of au atoms, respectively? 196.97 g and 196.97 amu 197 amu and 197 g 197 g and 197 amu 196.97 amu and 196.97 g none of the above

Answers

The mass of one Au atom is 196.97 amu from periodic table and the mass of Avogadro's number of Au atoms is 196.97 g due to this is the mass of one mole of gold

Explanation:

The mass number of an element is a weighted average of all the isotopes of that element.

If Au has only one isotope then the atomic weight of that isotope matches the mass number.

Au-197 ==> mass number 197

Mass of one atom=mass number 197 amu

Mass of one mol of atoms:

[tex]m=197 amu*1.66054*10^{-24}g/amu*6.022*10^{23}[/tex]

[tex]m=196.97 g[/tex]

the enthaply of a reaction can be measured using a ____

Answers

The answer is calorimeter. The amount of heat released or absorbed in the system inside the calorimeter can be measured since the calorimeter is insulated. Measuring the mass and the change in temperature of the system, and knowing the specific heat of the materials, we can then measure the heat transfer that is equal to the enthalpy of the reaction. 

Draw the lewis structure for the molecule ch3ch2cch. how many sigma and pi bonds does it contain?

Answers

Answer:
             The structure of 1-Butyne is shown below and it contains;

                                         Nine Sigma Bonds

                                             Two Pi Bonds

Explanation:
                     
In given structure the sigma bonds are highlighted with blue colour and pi bonds are highlighted by Black colour and indicated by red arrows.
                     Remember the very first covalent bond between two atoms is always the sigma bond. After formation of sigma bond if further p orbitals with unpaired electrons are available they will form pi bond, or two pi bonds as in given scenario.
Final answer:

The molecule CH3CH2CCH has a Lewis structure of H3C-CH2-C≡CH. It contains 11 sigma bonds and 2 pi bonds, which represent the different forms of covalent bonds due to the overlap of atomic orbitals.

Explanation:

The molecule CH3CH2CCH, also known as 1-Butyne, is composed of hydrogen (H) and carbon (C) atoms. Its Lewis structure can be represented as:

H3C-CH2-C≡CH.

Here, each line represents a bond between two atoms, which could be a sigma (σ) or a pi (π) bond. In the case of CH3CH2CCH, there are a total of 11 sigma bonds. You can see these as the bonds between H and C in the CH3 and CH2 groups, the single bond between the two C atoms in the center, and the bond between the last C and H atoms. As for the pi bonds, represented by two lines (double/triple bonds), there are 2, which can be seen in the triple bond of C≡C.

Sigma bonds represent the overlap of atomic orbitals to form a covalent bond, with the electron density concentrated along the internuclear axis. Conversely, pi bonds occur due to the side-by-side overlap of atomic orbitals where the electron density is concentrated on two parallel lines.

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What type of radioactive decay involves only the release of high-energy photons and therefore does not change the mass of an atom of a radioactive isotope?

Answers

Answer is: gamma emission or gamma decay.
During gamma emission the nucleus emits radiation without changing its composition, if for example have nucleus with six protons and six neutrons (carbon atom) and after gamma decay there is nucleus with six protons and six neutrons.
Gamma rays are the electromagnetic waves with the shortest wavelengths (1 pm), highest frequencies (300 EHz) and highest energy (1,24 MeV).

A solid fuel designed for a rocket has an air pocket inside. What is the DANGER OF THIS?

A. The rocket might not generate enough lift
B. The rocket might slow down and fall from space
C. The rocket might explode from the added pressure when the combustion reaction hits the air pocket
D. the rocket might not be able to regulate its speed

Answers

Answer:

C. The rocket might explode from the added pressure when combustion reaction hits the air pocket.

Explanation:

Correct answer for *APEX quiz!

The rocket might explode from the added pressure when combustion reaction hits the air pocket. Hence, option C is correct.

What is combustion?

Combustion is another word for burning. In a combustion reaction, a fuel is heated and it reacts with oxygen.

In a rocket engine , fuel and a source of oxygen, called an oxidizer, are mixed and exploded in a combustion chamber.

The combustion produces hot exhaust which is passed through a nozzle to accelerate the flow and produce thrust.

Hence, option C is correct.

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A certain radioactive material has a half-life of 36 minutes. Starting with 10.00 grams of this material, how many grams will be left after 2 hours?

A) 1.00 grams
B) 1.5 × 10-4 grams
C) 3.33 grams
D) 0.25 gram

Answers

I think it's c hope it's right

Answer: The correct answer is C) 3.33 grams

Explanation: 1/8 of the initial 10 grams is a little more than 1 gram, while 1/16 of 10 grams is a little more than 1/2 gram. The only answer that falls in that range is 1.00 gram. Use the integrated rate equation: ln(g0/gt) = kt, also ln(2) = kt1/2. Therefore k = (0.693)/36 min = 0.0193 min-1. In addition to the specific chemical properties that distinguish different chemical classifications, chemicals can exist in several phases. For the most part, the chemical classifications are independent of these bulk phase classifications; however, some more exotic phases are incompatible with certain chemical properties. A phase is a set of states of a chemical system that have similar bulk structural properties, over a range of conditions, such as pressure or temperature. Physical properties, such as density and refractive index tend to fall within values characteristic of the phase. The phase of matter is defined by the phase transition, which is when energy put into or taken out of the system goes into rearranging the structure of the system, instead of changing the bulk conditions.

Sometimes the distinction between phases can be continuous instead of having a discrete boundary' in this case the matter is considered to be in a supercritical state. When three states meet based on the conditions, it is known as a triple point and since this is invariant, it is a convenient way to define a set of conditions.

The most familiar examples of phases are solids, liquids, and gases. Many substances exhibit multiple solid phases. For example, there are three phases of solid iron (alpha, gamma, and delta) that vary based on temperature and pressure. A principal difference between solid phases is the crystal structure, or arrangement, of the atoms. Another phase commonly encountered in the study of chemistry is the aqueous phase, which is the state of substances dissolved in aqueous solution (that is, in water).

A condensation polymerization reaction produces a polymer and
1) H2
2) O2
3) CO2
4) H2O

Answers

Answer:
            Option-4 (H₂O) is the correct answer.

Explanation:
                   Condensation reactions are those reactions in which two molecules combine to form a macromolecule with the elimination of small molecules like H₂O, HCl, ROH as a byproduct.

Example:
              Amino acids (monomers) join together to form protein (polymer) with the elimination of H₂O molecules.
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