Homework answers and tutorials

Waiting for answer What is the percent composition of chromium in BaCrO4?
20.5% Cr. ##BaCrO_4## is 20.5% ##Cr## I found this answer by adding up the mass of one mole of ##Cr## and placing that number in the numerator. Then, total up the mass of ##BaCrO_4#...
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Waiting for answer What is the radius of a circle with circumference of 5 cm?
##0.796## ##"cm"## Circumference ##= 2pir## ##5 = 2pir## ##r= 5/(2pi)## ##r = 0.796 ##
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Waiting for answer Which are those two vectors whose resultant vector is zero?
Two opposite vectors (opposite directions) of same magnitude give you a zero resultant. In Physics, consider a force (a person pulling) on a crate and another force acting upon the same crate in the opposite direction give a zero resultant (basically if the crate was at rest remains at rest):
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Waiting for answer How did the Seven Years' War change the balance of power amo...
The seven Years' War is currently one of the most understated events in not just European, but World History by most people but not Historians!! Results Rise of Britain as the for...
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Waiting for answer One exterior angle of a regular polygon measures 10°. What i...
The interior angles of the regular polygon would each have a measure of ##170^o## The polygon would have 36 sides. The interior and exterior angles of a polygon form a linear pair a...
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Waiting for answer Draw the Lewis structure for HCOOH (1 H is bonded to an oxyg...
Yes, that's a rough description of how the for formic acid, ##HCOOH##, looks like. Here's how you'd go about drawing the Lewis structure for this compound. The molecule has a total number of 18 , 1 from each of the two hydrogen atoms, 4 from the carbon atom, and 6 from each of the two oxygen...
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Waiting for answer The sum of three consecutive integers is 75, what are the in...
Three consecutive integers can be written as ## (x) , (x+1) , (x+2)## Adding them: ## (x) + (x+1) + (x+2) = 75## ## 3x +3 = 75## ## 3x = 75  3 = 72## ## color(purple)(x = 72/ 3 = 24## so ,## x+1 = 25 , x+ 2 = 26## the numbers are ##color(purple)(24,25,26##
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Waiting for answer What is the standard equation of a circle with center ##(2,...
##(x+2)^2+y^2=16## The of a circle is. ##color(red)(bar(ul(color(white)(a/a)color(black)((xa)^2+(yb)^2=r^2)color(white)(a/a))))## where (a ,b) are the coordinates of the centr...
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Waiting for answer Describe the cell membrane, cell wall, nucleus, and cytoplas...
Nice. A long one Basic Definitions: = the semipermeable structure that surrounds the cell and keeps all of the cells organelles from exploding everywhere. Cell Wall = the rigid...
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Waiting for answer What is the formula of the expected value of a geometric ran...
If you have a geometric distribution with parameter ##=p##, then the expected value or mean of the distribution is ... expected value ##=1/p## For example, if ##p=1/3##, then the ex...
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Waiting for answer Calculate the number of molecules in 10.92 g of CCl4?
We know from the molecular mass that 1 mole of C##Cl_4## = 154 g/ mol , and we can use this information to make a conversion factor. In this case, first we are converting from grams to moles and then from moles to number of molecules. 1 mol of C##Cl4## has mass 154 g/mol 154 g of C##Cl4## mak...
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Waiting for answer A segment of steel railroad track has a length of 30,000 m w...
The lenght of the railroad at 40°C is: ##30,014.4m## The formula that we need is the thermal dilatation formula: ##l_2=l_1(1+lambdaDeltaT)##, where ##l_1## is the initial lenght, ##l_2## is the final lenght, ##lambda## is the coefficient of , ##DeltaT=T_2T_1## is the amount of incresing (if it...
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Waiting for answer Why were the reaper and the steel plow important?
These inventions were important because farmers no longer needed to hire workers, because they had new machinery. These workers moved to bigger cities and the employees of factories increased.
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Waiting for answer Explain why dogs pant during hot summer days using the conce...
They have hardly any sweat glands, and these wouldn't be useful anyway under all that fur. Evaporating water takes a lot of . By panting, the water on the dog's tongue is forcibly ev...
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Waiting for answer Is "hour" a countable noun? Is it an abstract noun?
It is a countable and abstract noun. A noun is countable if it has plural form and it can be used with numbers and word hour fulfills these conditions because you can say for example...
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Waiting for answer What is 75 miles per hour in kilometers per second?
##0.0335## ##(km)/h## We need to convert ##75## ##(mi)/h## into ##(km)/h## Cancel the hours in the denominator ##rarr75 (mi)/h*(1h)/(3600s)## (as ##1## hour is ##3600s##) ##rar...
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Waiting for answer What is the sample standard deviation formula?
s= ## [(xmean)/(n1)]^(1/2)## there is one difference between sample and population std deviation is degree of freedom. In sample , n observations are free to change whereas 1 is not that is use for estimating a population parameter.
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Waiting for answer What is Graham's Law of Effusion?
Technically, it’s Graham’s Law of Effusion. The molecules of a gas are in constant motion, colliding with each other and with the walls of the container. The average distance that a molecule travels between collisions (about 0.1 µm or 300 times the molecular diameter for N₂ at STP) is called its me...
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Waiting for answer What are some examples of diseases and disorders of the musc...
Myalgia, myositis, Muscular dystrophy, myasthenia gravis, tendinitis, tetanus, polio. Myalgia means muscle pain. Myositis means inflammation of muscular tissue. Muscular dystrophy is...
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