Answer:
сфоткай отправь. я не магу зделать
According to the concept of Avogadro's number, there are 29.056×10²³ molecules in 77.2 g of methane.
What is Avogadro's number?Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number
In the given example, number of moles=77.2/16=4.825 moles
If 1 mole has 6.023×10²³ molecules , then 4.825 moles will have 4.825×6.023×10²³ /1=29.056×10²³ molecules .
Thus, there are 29.056×10²³ molecules in 77.2 g of methane.
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According to the following reaction, how many moles of calcium chloride will be formed upon the complete reaction of 27.9 grams of calcium hydroxide with excess hydrochloric acid? calcium hydroxide (aq) + hydrochloric acid (aq) calcium chloride (aq) + water (l) moles calcium chloride
Answer: 0.377 moles of calcium chloride will be formed.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Ca(OH)_2=\frac{27.9g}{74g/mol}=0.377moles[/tex]
The balanced chemical reaction is:
[tex]Ca(OH)_2+2HCl\rightarrow CaCl_2+2H_2O[/tex]
According to stoichiometry :
As 1 mole of [tex]Ca(OH)_2[/tex] give = 1 mole of [tex]CaCl_2[/tex]
Thus 0.377 moles of [tex]Ca(OH)_2[/tex] give =[tex]\frac{1}{1}\times 0.377=0.377moles[/tex] of [tex]CaCl_2[/tex]
Thus 0.377 moles of calcium chloride will be formed upon the complete reaction of 27.9 grams of calcium hydroxide with excess hydrochloric acid
If 80% of the moths are dark and you have 80 moths, how
many would be dark??
Answer:
the answer is 64 moths are dark
alquien por favor que me ayude con ejercicios de química orgánica?
dime cómo es el trabajo y veo si te puedo ayudar
A mixture of cyclopropane (C3H6) and oxygen (O2) is sometimes used as a general anesthetic. In a mixture, the partial pressures of cyclopropane and oxygen are 170. torr and 570. torr, respectively. Calculate the ratio of the moles of oxygen to the moles of cyclopropane in the mixture.
Answer:
0.30
Explanation:
Provided that the volume and pressure remains constant
[(Pressure of cyclopropane)/ (Pressure of Oxygen)] = [(no. Of moles of cyclopropane)/(no. Of moles of Oxygen)]
Pressure of cyclopropane= 170. torr
Pressure of Oxygen= 570. torr
If we substitute the values
[(no. Of moles of cyclopropane)/(no. Of moles of Oxygen)] = 170/570
[(no. Of moles of cyclopropane)/(no. Of moles of Oxygen)] = 0.30
Hence, the ratio of the moles of oxygen to the moles of cyclopropane in the mixture is 0.30
If an oxygen molecule is moving at 4.78 x 104
cm.s-, what is its speed in mi hrl?
Show work please
Answer: 1075.5 mph
Explanation:anything moving at 4.78*10^4 cm/sec
equivalent to
cm —> miles = 1/1.6*10^5
sec —> hr = 1/3600
[4.78*10^4]*3600/1.6*10^5 = 1075.5 mph
Identify the components of the ionic formula based on the name strontium phosphide. What is the symbol for the element that forms the positive cation? What is the symbol for the element that forms the negative anion? What is the subscript on the cation in the neutral formula? What is the subscript on the anion in the neutral formula?
Answer: The components are Strontium (Sr) and Phosphorous (P). The symbol for the element that forms the positive cation is [tex]Sr^{2+}[/tex]. The symbol for the element that forms the negative anion is [tex]P^{3-}[/tex]. The subscript on the cation in the neutral formula is 3 and the subscript on the anion in the neutral formula is 2.
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here in strontium phosphide , element strontium is having an oxidation state of +2 called as [tex]Sr^{2+}[/tex] cation and element phosphorous [tex]P^{3-}[/tex] is an anion with oxidation state of -3. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral strontium phosphide [tex]Sr_3P_2[/tex]
Which of the following observations about burning sugar provides evidence of a
chemical reaction?
a. Heat is added to the sugar crystals.
b. The sugar melts and becomes a liquid.
с
C. The temperature of the sugar increases.
d. Gas is produced as the sugar turns black.
1 Pt
А
B
D
what is the chemical symbol for fluoride
Answer:
I think F
Explanation:
The photograph shows one of the boats in a science club's toy boat race. All the boats were powered by identical
rubber bands. Judges used stopwatches to time how long each rubber band took to unwind. The table shows some
of the data the judges collected.
Boat
Time
(5)
Acceleration
(m/s)
N
1.6
1.4
1.1
Mass of
Boat (kg)
0.125
0.116
0.130
0.118
P
Penywise/Dreamstime.co
Q
1.5
1.2
2.1
1.0
1.8
R
Which boat experienced the greatest unbalanced force?
Answer:
Boat p
Explanation:
Answer:
boat p
Explanation:
20 g of Allg is dissolved in water to produce a solution with a concentration of 2.007M. What is the volume of this solution in milliliters?
Answer:
369 ml
Explanation:
Mass of Aluminium (Al) = 20 g
Molar concentration = 2.007M
Molar concentration = Number of moles / Volume
The relationship between mass and number of moles;
Number of moles = Mass / Molar mass
Number of moles = 20 / 27 = 0.741 mol
2.007 = 0.741 / Volume
Volume = 0.741 / 2.007 = 0.369 L
converting to millilitres by multiplying by 1000
Volume = 0.369 * 1000 = 369 ml
3. Match each of the following descriptions with one of the beakers in Model 1. In each case, assume the change in volume as the solid(s) are added is minimal. a. A 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of water in beaker . b. A 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.500 M sodium hydroxide solution in beaker . c. A 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.200 M sodium hydroxide solution in beaker . d. A 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.200 M calcium nitrate solution in beaker . 4. Based on the solubility product constant, Ksp, for calcium hydroxide given in Model 1, do you expect most of the 1.00 mole sample of solid to dissolve in any of the four beakers
Answer:
Explanation:
When calcium hydroxide is dissolved in water , it ionizes as follows .
Ca( OH)₂ = Ca⁺² + 2 OH ⁻
When it is dissolved in water which contains minimal OH⁻ , so there is almost no common ion effect . Hence calcium hydroxide is fully dissolved in pure water solvent .
When 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.500 M sodium hydroxide solution in beaker , it is not fully dissolved due to common ion of hydroxide ion ( OH⁻ )
NaOH = Na⁺ + OH⁻
OH⁻ ion from NaOH , suppresses the dissolution of calcium hydroxide .
Similarly
When A 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.200 M sodium hydroxide solution in beaker , it is not fully dissolved due to common ion of hydroxide ion ( OH⁻ )
NaOH = Na⁺ + OH⁻
OH⁻ ion from NaOH , suppresses the dissolution of calcium hydroxide
When 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.200 M calcium nitrate solution , it is not fully dissolved due to common ion of calcium ion ( Ca⁺² )
Ca( NO₃)₂ = Ca⁺² + 2NO₃⁻
Ca⁺² ion from Ca( NO₃)₂ , suppresses the dissolution of calcium hydroxide .
given mass of sodium sulphate contains 1.052 moles of oxygen atom then moles of sodium atom present in it would be equal to (ans=0.526)
how to solve this please help me...!
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The elements listed in the periodic table account
for only this percentage of the matter in
the universe.
Answer:
Only 4 %
Explanation:
Just about 4 percent of the known universe overall mass consists of atomic nuclei and is therefore described by chemical components. This proportion is around 15 percent of the total mass, with dark energy becoming the majority of the material .
Help !!A student examines a picture of an important biological molecule in a textbook and writes four statements about the molecule in a chart
1. The molecule is found in the nucleus,
2. The molecule is made up of chromosomes.
3. The molecule carries genetic information.
4. The molecule contains genes.
Which statement needs to be revised to make it true? statement 1 statement 2 statement 3 statement 4
Answer:
Statement 2 (The molecule is made up of chromosomes)
Explanation:
This question is describing DNA, as the biological molecule. DNA is a type of nucleic acid that functions in the storage of genetic information in the cell. This means that contained in the DNA, are segments that code for proteins called GENES. It is contained in the nucleus of eukaryotic cells where it is wrapped around structures called CHROMOSOMES.
BASED on the four statements given by the student, which happens to be characteristics of this molecule, the statement 2, which states that the molecule is made up of chromosomes needs to be revised to make it true. This is because DNA is not made up of chromosomes but rather DNA is contained in chromosomes.
HURRY WHICH ONE IS IT??
Answer:
Protons are positive, electrons are negative, neutrons have to charge. Most of an Atoms mass comes from its protons and neutrons
Explanation:
I took some notes in my notebook about Atoms.
what are the three important properties of acids
Convert 3.93 x 10-22 grams of X4Z3 into molecules/formula units of the same compound. (Assume that the molar mass of X is 59.45 grams per mole and the molar mass of Z is 13.84 grams per mole.)
Assume that Avogadro's number is 6.022 x 1023. Report your answer to three decimal places.
Answer:
0.847 molecule.
Explanation:
From the question given above, the following data were obtained:
Mass of X₄Z₃ = 3.93×10¯²² g
Number of molecules of X₄Z₃ =?
Avogadro's number = 6.022×10²³ molecules
Next, we shall determine the molar mass of X₄Z₃. This can be obtained as follow:
Molar mass of X₄Z₃ = (4×59.45) + (3×13.84)
= 237.8 + 41.52
= 279.32 g/mol
Finally, we shall determine the number of molecules in 3.93×10¯²² g of X₄Z₃. This can be obtained as follow:
From Avogadro's hypothesis,
1 mole of X₄Z₃ = 6.022×10²³ molecules
But 1 mole of X₄Z₃ = 279.32 g
Thus we can say that:
279.32 g = 6.022×10²³ molecules
Therefore,
3.93×10¯²² g = 3.93×10¯²² × 6.022×10²³ / 279.32
3.93×10¯²² g = 0.847 molecule.
Thus, 3.93×10¯²² g of X₄Z₃ contains 0.847 molecule.
Which best describes a hydrate?
A.) It has water molecules bonded directly to it.
B.) It lacks water molecules ik it’s crystal lattice.
C.) It lacks hydrogen and oxygen atoms, which make up water.
D.) It has water molecules incorporated into its crystal lattice.
Draw the structure of the peptide DTLH, showing the backbone and side-chain atoms, at its isoelectric point. Draw the molecule on the canvas by choosing buttons from the Tools (for bonds and charges), Atoms, and Templates toolbars. Draw peptide molecule as zwitter ion.
Answer:
Explanation:
A peptide is any class of organic compounds composed of different numbers of amino acids in which the amine of one is reacted with the carboxylic acid of the next to form an amine bond. The peptide of DTLH is composed of the following amino acids:
Asp-Thr-Leu-His
Their structures are first drawn out in the image attached below. This is followed by the isoelectric structure of the peptide DTLH
When Lithium chloride is dissolved in water, there is a steep rise in the temperature of the water. Based on the evidence, is the dissolution of lithium chloride endothermic, exothermic, or neither? Explain.
Answer:
When some LiCl is dissolved in water, the temperature of the water increases. This means that: (A) the strength of the intermolecular forces between the water molecules is stronger than the bond energy within the LiCl lattice.
Explanation:
When Lithium chloride is dissolved in water, there is a steep rise in the temperature of the water. Based on this evidence, the dissolution of lithium chloride is exothermic.
What is an Exothermic reaction?An exothermic reaction may be defined as a type of reaction in which energy is liberated as a product in the form of light or heat. For these types of reactions, the overall standard enthalpy change ΔH⚬ is negative. It is one of the thermodynamic processes other than endothermic.
In the reaction, lithium intensely reacts with water in order to form lithium hydroxide and highly flammable hydrogen which liberated energy and leads to the steep rise in the temperature of the product compounds. This enhancement in the temperature is accurate evidence of an exothermic reaction.
Therefore, on the basis of the evidence that the reaction of lithium chloride in water causes a steep rise in the temperature of the water represents an exothermic reaction.
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Which part of the atom was discovered last?
Answer: The nuetron was
Explanation: sorry is this is incorrect but im
99% its right
True or False Weather is the condition or earth's atmosphere at a certain place and time.
Answer:
True
Explanation:
Weather is short term, climate is over the long term
Answer:
true, different weather patterns are found all around the world at different times, there could be a hurricane in the gulf of mexico and as a result of the storm tornadoes could break out in texas
Explanation:
For the reaction between zinc metal and hydrochloric acid (aqueous) producing zinc chloride (aqueous) and hydrogen gas
write a balanced equation for this reaction
classify the reaction
Answer: Zn + 2HCl —> ZnCl2 + H2 redox
Explanation:
H+ reduced to H
Zn oxidised to Zn++
Steel is an alloy of iron and carbon. The addition of carbon to iron enhances which of the following properties of iron metal?
O A hardness
O B. malleability
O C. ductility
O D. softness
Answer:
The answer should be A. Adding carbon to iron makes it tougher and stronger.
The addition of carbon atom to iron metal, enhances the property of hardness of metal.
What is alloy?Alloy is a compound which is formed by the mixture of two or more than two metals with different properties to make a new compound with better properties.
When we add carbon atom in the iron metal, it deviates the crystal lattice property of iron and makes it more harder. So, the content of carbon in the iron is directly proportional to the hardness of iron metal.
Hence, option (A) is correct i.e. hardness.
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What is a common effect of warm ocean currents on nearby coastlines?
A. Low wind speeds
B. Lower temperatures
C. Changing wind directions
D. Increased clouds and precipitation
Which of the following describes how the mid Atlantic ridge formed on earth at a divergent plate boundary.
A Plates move in closer
B Plates slid past each other
C Plates moved with each other in the same direction
D Plates moved apart
Srry couldn’t find science
Answer:
Maybe (C)
...............
Answer:
A. plates move in faster
Explanation:
The convergence is a process where both the plates tend to move in closer as one plate overrides the other and the formation of a Himalayas is described as a range that formed by the movement of the sediments that were bought by the Tethys sea. By the collision of the Indian and the Eurasian plate.
i hope this helps
Atmospheric pressure decreases as altitude increases. In other words, there is more air pushing down on you at sea level, and there is less air pressure pushing down on you when you are on a mountain.
If hexane (C6H14C6H14), octane (C8H18C8H18), and octanol (C8H17OHC8H17OH) are heated evenly at different altitudes, rank them according to the order in which you would expect them to begin boiling.
A) Hexane at high altitude.B) Octane at high altitude.C) Octane at sea level.D) Octanol at sea level.
Answer:
Octanol at sea level> Octane at sea level > Octane at high altitude > Hexane at high altitude
Explanation:
Let us have it behind our minds that the boiling points of alkanes depends on the length of the alkyl chain. The longer the chain length, the higher the boiling point of the alkane.
Also, octanol has hydrogen bonding between its molecules in addition to dispersion forces, hence it has a higher boiling point than octane and hexane at sea level.
So, the order of boiling points required at the specified altitudes is;
Octanol at sea level> Octane at sea level > Octane at high altitude > Hexane at high altitude
What can you infer about the growth of the seed type pictured in the graphs below? ( Note, the vertical axis represents the number of seeds )
The graph shows Time in days from 0 to 5 on the x-axis and 0 to 100 on the y-axis with 5 percent light. Day 0 there are 100 seeds and 0 sprouts. The number of seeds and sprouts remains the same through 2.5 days. Then the number of seeds decreases while the number of sprouts increases. Day 5 there are 30 seeds and 70 sprouts.The graph shows Time in days from 0 to 5 on the x-axis and 0 to 100 on the y-axis with 80 percent light. Day 0 there are 100 seeds and 0 sprouts. The number of seeds and sprouts remains the same through 2.5 days. Then the number of seeds decreases while the number of sprouts increases. Day 5 there are 30 seeds and 70 sprouts.
a.
More seeds grow with more light.
b.
More seeds grow with less light.
c.
The seeds grow faster with more light.
d.
Light has no effect on seed growth.
Answer:
D
Explanation:
I just did it on Edge
Answer:It’s D
Explanation: It was in my test
I can ride my bicycle at a velocity of 5.655 X 10° um/sec. Is this fast or slow? Prove your answer by converting into km/hr.
answer ASAP
Answer:
56/hr
Explanation:
The diagram shows the electron configuration around the chlorine nucleus. Chlorine has 17 protons.
CI
Which of the following correctly completes the statement?
Chlorine has valence electrons, and the effective nuclear charge, Zett, for the chlorine atom shown is
O A. 7,7+
OB. 7,7-
O C. 10,7-
D. 17, 7+
Answer: A. [tex]7,+7[/tex]
Explanation:
Valence electrons are the number of electrons constituting the outermost shell of an atom. It is also defined as the electrons that take part in the formation of a chemical bond.
The atomic number of chlorine is 17 as it has 17 protons and the electronic configuration will be 2,8,7. Thus the electrons present in the outermost shell are 7 and hence the valence electrons are 7.
Effective nuclear charge is the net positive charge experienced by valence electrons. It is calculated by: Zeff = Z – S
where Z = atomic number , S = number of shielding electrons.
Thus for Chlorine , [tex]Z_{eff}=17-10=7[/tex]