Railroad tracks built with a flexible expansion and contraction joint because the tracks have a larger coefficient of linear expansion than the ground beneath. Hence, Correct opotion is option (A)
Where is linear expansion used?The linear expansion of a solid under a change in temperature can be measured using Δℓ/ℓ = αΔT and has applications in the ways solids expand and contract in everyday life.
The strain that the object undergoes has implications in engineering when fitting objects among each other.
Hence, Railroad tracks built with a flexible expansion and contraction joint because the tracks have a larger coefficient of linear expansion than the ground beneath. Therefore, Correct opotion is option (A)
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A sample of gas collected at 685 mm Hg occupies 131 mL. At constant temperature, what pressure does the gas exert if the volume increases to 478 mL? a. 188 b. 1320 c. 128 d. -88.8
Answer:
a. P=188mmHg
Explanation:
A gas undergoing a change of volume and pressure at constant temperature (and not changing the number of molecules), follows Boyle's Law: [tex]P_1V_1=P_2V_2[/tex]
The units of these quantities can be any measure of pressure and volume, so long as long as the units are the same between beginning and ending conditions.
Substitute and solve:
[tex]P_1V_1=P_2V_2[/tex]
[tex](685[mmHg])(131[mL])=P_2(478[mL])[/tex]
[tex]\dfrac{(685[mmHg])(131[mL\!\!\!\!\!\!\!\!\!{--}])}{478[mL\!\!\!\!\!\!\!\!\!{--}]}=\dfrac{P_2(478[mL]\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----})}{478[mL] \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----}}[/tex]
[tex]187.730125523[mmHg]=P_2[/tex]
Accounting for significant figures, [tex]P_2=188[mmHg][/tex]
Identify different hydro-meteorological hazards;
Hydrometeorological hazards are caused by extreme meteorological and climate events, similar as cataracts, famines, hurricanes, tornadoes, or landslides.
Hydrometeorology it’s a branch of meteorology and hydrology that studies the transfer of water and energy between the land face and the lower atmosphere.They regard for a dominant bit of natural hazards and do in all regions of the world, although the frequency and intensity of certain hazards and society’s vulnerability to them differ between regions. Severe storms, strong winds, cataracts, and famines develop at different spatial and temporal scales, but all can come disasters that beget significant structure damage and claim hundreds of thousands of lives annually worldwide. hourly, multiple hazards can do contemporaneously or spark slinging impacts from one extreme rainfall event.In addition to causing injuries, deaths, and material damage, a tropical storm can also affect in flooding and mudslides, which can disrupt water sanctification and sewage disposal systems, beget overflow of poisonous wastes, and increase propagation of mosquito- borne conditionsTherefore these are the hydro-meteorological hazards.
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The thermite reaction reacts iron (III) oxide, Fe2O3, with aluminium powder,Al, the form aluminium oxide, Al2O3 and iron, Fe.
A. a student reacted 16.0g of iron with 8.1g of aluminium powder. which of the two reactants is the limiting reagent? Show your working.
B. Calculate the maximum mass of iron of iron that could be formed using these quantities of reactants.
Answer:
This answer assumes that the strated "16.0g of iron" was meant to be 16.0 grams of iron(III) oxide.
Explanation:
To start, the thermite equation must be balanced.
I find:
1Fe2O3 + 2Al = 1Al2O3 + 2Fe
This tells us we need 2 moles of Al for every 1 mole of Fe2O3.
Now calculate the moles of each reactant:
Moles Fe2O3: 16.0 g/159.7 g/mole = 0.100 moles Fe2O3
Moles Al: 8.1 /26.98 g/mole = 0.300 moles Al
The balanced equation says that in order to react all of the Fe2O3 we'd need twice that amount (in moles) of the Al. (0.100 moles Fe2O3)*(2) = 0.200 moles Al.
Which of the two reactants is the limiting reagent?
We have more than enough moles of Al to react with 0.10 moles of Fe2O3. (We have 0.300 moles Al and all we need is 0.200 moles to react with the 0.10 moles of Fe2O3. Fe2O3 is the limiting reagent.
Calculate the maximum mass of iron of iron that could be formed using these quantities of reactants.
The balanced equation tells us that we will obtain 2 moles of Fe for every 1 mole of Fe2O3 consumed. Since Fe2O3 is the limiting reagent, we will assume that it completely reacts. That means 0.1 moles of Fe2O3 is reacted. Since we expect twice that many moles of Fe, we should obtain 0.200 moles of Fe. At 55.85 g/mole, we should obtain:
(0.200 moles Fe)*(55.85 g Fe/mole Fe) = 11.2 grams Fe
2. four bulbs connoted in parallel controlled by a single pole switch using
alternating current
Answer
I think there should be two poles, a north pole and a south pole. so this statement is wrong
Hydrogen and Oxygen will have ______ properties after they bond to become water.
A. only the dominant element’s
B. both of their original
C. the same
D. completely new
A hydrate of zinc nitrate has the formula Zn(NO3)2 . xH2O. If the mass of 1 mol of anhydrous zinc nitrate is 63.67% of the mass of 1 mol of the hydrate, what is the value of x?
MM Zn(NO₃)₂ = 189.36 g/mol
mass 1 mol Zn(NO₃)₂ = 189.36 g
mass hydrate = 100 / 63.67 x 189.36 = 297.409 g
mass 1 mol hydrate = 297.409 g
MM hydrate = 297.409 g/mol
MM hydrate = MM Zn(NO₃)₂ + MM xH₂O
297.409 = 189.36 + x(18)
x = 6
Which of the following species of fish have cartilaginous skeletons?
Answer:
sharks have cartilaginous skeletons
Explanation:
Sharks are an example
Which phrase describes a homogeneous catalyst?
Answer:
It is in the same phase as the reactants.
Explanation:
i took the test
The AP Biology teacher is measuring out 638.0 g of dextrose (C6H12O6) for a lab. How many moles of dextrose is this equivalent to?
The AP Biology teacher is measuring out 638.0 g of dextrose (C6H12O6) for a lab the moles of dextrose is this equivalent to is 3.6888 moles.
What are moles?A mole is described as 6.02214076 × 1023 of a few chemical unit, be it atoms, molecules, ions, or others. The mole is a handy unit to apply due to the tremendous variety of atoms, molecules, or others in any substance.
To calculate molar equivalents for every reagent, divide the moles of that reagent through the moles of the restricting reagent. The calculation is follows:
655/12 x 6 + 12+ 16 x 6 = 655/ 180 = 3.6888 moles.Read more about moles:
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An exergonic reaction __________ free energy, and an endergonic reaction __________ free energy.
Answer:
An exergonic reaction releases free energy, and an endergonic reaction absorbs free energy.
Explanation:
hope it helps
An educated guess which explains observations is called:
a a law
b an experiment
c a hypothesis
d a variable
Answer:
c. a hypothesis is the correct answer
Explanation:
A 35. 0-l steel tank at 20. 0?c contains acetylene gas, c2h2, at a pressure of 1. 39 atm. Assuming ideal behavior, how many grams of acetylene are in the tank?.
52.66 grams of acetylene are in the tank.
PV=nRT is the formula for ideal gases, where P is the pressure and R is the constant and T is the temperature (P is 1.39 atm in this case)
Volume = 35.0 L
Gas constant = 0.08206 L.atm/K.mole
Temperature = 20.0 °C = 293 °C
We also know that we can apply the formula ;
Number of mole(n) = [tex]\frac{MmPV}{RT}[/tex]
m = ( 26.04 × 1.39 × 35 )/ (0.08206 × 293.15)
m = 52.66 g
Thus, the mass is 52.66 grams.
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How can i calculate the concentration of 2.357g of sodium chloride in 75ml solution
Answer:
See below
Explanation:
Simply : 2.357 g / 75 ml = .03142 gm/ml or 31.42 gm / liter
It is the year 2040, and you are a research scientist. The amount of sunlight that reaches the earth has been drastically reduced due to a major event like pollution, fires, or volcanoes. Farmers are asking you for help to save their failing crops.
You mass two substances. One substance has a mass of 22.45 g and the other has a mass of 3.1 g. What is the total mass of both objects?
Answer:
25.55 g
Explanation:
To find the total mass of both objects, you need to add the masses together.
22.45 g + 3.1 g = 25.55 g
In correct significant figures (2 sig figs to match 3.1 g), the value would be 26 g.
Answer:
answer = 25.55
Explanation:
You just have to add the mass of the two objects
The molecular structure of water has an asymmetrical arrangement of hydrogen atoms causing.
Answer:
the asymmetrical arrangement of hydrogen atoms in a molecule of water causes the molecule to be polar, with the hydrogen atoms having a slightly positive charge, and the oxygen atom having a slightly negative charge.
In 2007, the population of Canada was 1.26 × 108, the population of Mexico was 10.6 × 107, the population of Brazil was 13.6 × 107, and the population of China was 1.86 × 109. Which two countries have the highest population?
A. Canada and China
B. Mexico and China
C. China and Brazil
D. Brazil and Mexico
Which of the following statements are true of thermal energy and kinetic
energy?
Check all that apply.
A. All the molecules or atoms in motion have kinetic energy.
B. All the molecules or atoms in motion have thermal energy.
C. Each molecule or atom in motion has thermal energy.
D. Each molecule or atom in motion has kinetic energy.
Answer:
A. All the molecules or atoms in motion have kinetic energy.
B. All the molecules or atoms in motion have thermal energy.
C. Each molecule or atom in motion has thermal energy.
D. Each molecule or atom in motion has kinetic energy.
Explanation:
There are 4.9875 mol C, 7.9802 mol H,
and 2.00 mol O in the sample.
Divide each by the smallest number of
moles. What is the ratio for the H?
did anyone able to look up this question
the ratio for the H is 3.9901
1s22s²2p63s23p64s²3d104p5
Which element is this?
Answer: bromine
Explanation:
There are a total of 2+2+6+2+6+2+10+5=35 electrons, meaning there are 35 protons. The element with atomic number 35 is bromine
Grams in 1.083e+24
Molecules Na BR
Please help explain why
Answer:
185 gms o NaBr
Explanation:
Na Br mole weight = 22.989 +79.904 = 102.893 gm/mole
1.083 x 10^24 molecules / 6.022 x 10^23 molecules / mole = 1.798 moles
102.893 * 1.798 = 185 gms
The cutoff frequency for a certain element is 1.22 x 1015 Hz. What is its work function in eV?
Hint: 1 eV 1.60 x 10-19 J
=[?] eV
someone please teach me how to solve this its gonna make me cry
The work function of the metal is obtained as 5.1 eV
What is the cutoff frequency?The cutoff frequency is the frequency below which photo electric effect can not occur as electrons are not removed from the metal surface.
Now;
fo = 1.22 x 10^15 Hz
Wo = hfo
Wo = 6.6 * 10^-34 * 1.22 x 10^15
Wo = 8.1 * 10^-19 J
If 1 eV = 1.60 x 10-19 J
x eV = 8.1 * 10^-19 J
x = 8.1 * 10^-19/ 1.60 x 10-19
x = 5.1 eV
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Which type of electromagnetic wave has less energy than a microwave?
OA. Ultraviolet wave
OB. Radio wave
O C. An X-ray
OD. Infrared wave
How many atoms are present in 2.1 moles of Fe
Answer:
1.3 x 10²⁴ atoms Fe
Explanation:
To convert moles to atoms, you need to multiply your given value by Avogadro's Number. This causes the conversion to occur because Avogadro's Number exists as a ratio. It is the ratio that allows for the cancellation of units during multiplication. This is why atoms should be in the numerator of your conversion. The final answer should have 2 sig figs to reflect the given value.
Avogadro's Number:
1 mole = 6.022 x 10²³ atoms
2.1 moles Fe 6.022 x 10²³ atoms
--------------------- x ------------------------------- = 1.3 x 10²⁴ atoms Fe
1 mole
How many individual Ni atoms are contained in 1.25 grams of Ni? (Input your answer with scientific notation using "e-notation" and report your answer to two places past the decimal point.
Answer:
Ni atoms are contained in 1.25gram is 1.28e22 atoms.
Explanation:
Ni atoms are contained in 1.25gram is 1.28e22 atoms.
We have a Nickel(Ni) atom . The atomic number of Ni is 28 .It is a silvery-white metal with a slight golden tinge. Ni belongs to the transitional metal series.
The electronic configuration of Ni = Ar4d⁸35²
Nickel is slowly oxidized by air at room temperature.
Nickel is a ferromagnetic element at approximately room temperature.
To answer the problem , we first need to divide by the molar mass of Ni to get the moles of Ni. And then we will multiply by Avogadro's number to find the number of Ni atoms.
Molar mass of Ni = 58.7gm
Given mass of Ni = 1.25gm
Avogadro’s No. = 6.022 × 10²³ atom/mole
Moles of Ni = Given mass/Molecular mass
= 1.25/58.7 = 0.0213
Moles of Ni = 0.0213
Now ,
Number of Ni atom = Avogadro’s number × Moles
So that,
No. of Ni atom = 6.022 × 10²³× 0.0213
= 0.128 ×10²³ atoms
= 1.28 × 10²² atoms
= 1.28e22
So there are 1.28 × 10²² individual Ni atoms are contained in 1.25 grams of Ni.
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Compare
Ion and Radical
Atom and molecule
Organic and inorganic compounds
Answer:
'An ion has a non-zero electric charge. A radical has an atom with unfilled electron shells and so is very reactive, but is electrically neutral.'
'Atoms are single neutral particles. Molecules are neutral particles made of two or more atoms bonded together.'
'The primary difference that lies between these organic compounds and inorganic compounds is that organic compounds always have a carbon atom while most of the inorganic compounds do not contain the carbon atom in them.'
Organic and inorganic compounds:
Similarities:::---
1) In both organic and inorganic compound, the elements joining in making compound complete their octet.
2) Organic compound shows isomerism (R/S , E/Z , cis/trans, enantiomers, diastereomers, etc), just as inorganic compound do (Δ/Λ, enantiomers, R/S enantiomers, cis/trans, fac/mer isomers, etc).
3) Organic compound and inorganic compounds can be very active in chemical reactions, e.g. organolithium reagents could be flammable or even pyrophoric (generally stored under 10°C), while inorganic reagents like in this paper are quite rapid...
Differences:::---
1) Organic compound are very long in size so they can make polymer but inorganic compound are not very long but its structure might me complex.
2) The boiling,melting point of organic compound is lass than inorganic compound.
3) Organic compound always contains carbon but inorganic compounds might not.
4) Organic compound
_____________________________
Ion and Radical Atoms:
In some sense they are a bit similar. The main difference is that a neutral radical has no charge imbalance between the protons and electrons, but the cation or anion does.
Ions are written with an explicit charge because of that charge imbalance, but radicals may or may not have an imbalance of charge. Just because a molecule is a radical doesn't mean it's neutral.
For example, if you shoot 2-pentanone with an electron beam for Electron "Impact" Mass Spectroscopy, where you essentially study molecules whose structures break into smaller pieces as a result of interacting with stray electrons to identify the molecules, you get a cationic radical (middle, or far right of the following diagram).
what is the approximate distance from the far edge of one lobe to the far edge of the other?
The approximate distance from the far edge of one lobe to the far edge of the other is 2,100,000 light-years.
What is distance between far edge of two lobes in solar system?
This distance measures the outer space between the edges of the two lobes in a given time.
The approximate distance from the far edge of one lobe to the far edge of the other in a solar system is about 2,100,000 light-years.
Thus, the approximate distance from the far edge of one lobe to the far edge of the other is 2,100,000 light-years.
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Which two protests evolved from symbolic relationships of organism which resulted in eukaryotic organisms chloroplast
Red algae and euglena evolved from a symbiotic relationship of organisms, which resulted in eukaryotic organisms containing chloroplasts
Theory of endosymbiosis:
Early eukaryotes developed by the symbiotic connection of prokaryotes, in accordance with the endosymbiosis idea. Which two protists underwent symbiotic evolution, leading to the development of eukaryotic creatures with chloroplasts.
-Symbiotic relationships between two or more prokaryotic cells led to the evolution of the first eukaryotic cells. Greater prokaryotic cells invaded or devoured smaller prokaryotic cells. The connection provided a secure home and nourishment for the tiny cells. By absorbing part of the organic molecules or energy generated by the endosymbionts, the bigger cells (now referred to as hosts) profited.
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In photosynthesis, plants use energy from the sun to produce glucose, c6h12o6 , and oxygen from the reaction of carbon dioxide and water.
6co2 + 6h2o --> c6h12o6 + 6o2
what mass, in grams, of glucose is produced when 3.00 mol of water react with carbon dioxide?
Answer: 324 g (to 3 sf)
Explanation:
Based on the coefficients of the equation, we know that when 3.00 mol of water is consumed, 3.00 mol of carbon dioxide is also consumed.
The atomic mass of carbon is 12.011 g/mol.The atomic mass of oxygen is 15.9994 g/mol.Thus, the formula mass of carbon dioxide is:
[tex]6(15.9994)+12.011=108.0074[/tex] g/mol.
Thus, 3.00 mol has a mass of (108.0074)(3.00)=324 g (to 3 sf)
A 126.1-gram block of granite at 92.6°c is dropped into a tub of water at 24.7°c in an isolated system. the final temperature of both the granite and the water is 51.9°c. the specific heat capacity of granite is 0.795 joules/gram degree celsius, and the specific heat capacity of water is 4.186 joules/gram degree celsius. the granite block transferred of energy, and the mass of the water is .
The granite block transferred 4,080 joules of energy, and the mass of the water is 35.8 grams.
How we calculate heat transfer of any system ?Heat transfer in any system can be calculated as follow:
q = mCΔT
Given ;
m = mass of granite = 126.1 g C = specific heat of granite = 0.795 joules/gram degree CelsiusΔT = change in temperature of granite = 51.9 °C - 92.6 °C = -40.7 °CPutting all the values in folowing equation,
q = mCΔT
we get
q = 126.1 × 0.795 × -40.7 = -4080 J
Now by using same formula, we can also calculate the mass of water in the following way:
m = q / CΔT
where
C = specific heat of water = 4.186 joules/gram degree Celsius ΔT = change in temperature of water = 51.9 °C – 24.7 °C = 27.2 °CPutting all these values ;
m = -4080 / 4.186 × 27.2 = 35.8 g.
Hence, 4,080 joules of energy is transferred by granite block and 35.8 g is the mass of water.
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