# Posts by Annie

Total # Posts: 823

**chemistry**

delta h= -5113.3

**chemistry**

for a particular isomer C8H18, the following reaction produces 5113.3 kj of heat per mole of C8H18 consumed under standard conditions c8h18(g) + 25/2 O2 (g) ---> 8co2(g) + 9h2o(g) what is the standard enthalpy of formation of this isomer of c8h18? o2= 0 co2(g)= -393.5 h2o(g...

**Chemistry**

Which of the following substances have a standard heat of formation of zero? O2 at 25.O degrees C and 1 atm Fe at 1200 degrees C C2H6 at standard conditions Cl2 at 2 atm

**Business Math**

March 31-21 (Date of note)=10 days remaining. Take the 60 days-10 (days remaining in march)=50-30 (days in April)=20 days So, the maturity date of the note is May 20th.

**Math**

I=PRT I=40,000*.14*25/360=$388.89 (interest) $15,000-388.89=$14,611.11 (amt. of partial payment left to reduce the principal) 40,000-14,611.11=$25,388.89 (adjusted principal balance) $25,388.89*.14*20/360=197.47 10,000-197.47=9802.53 25,388.89-9802.53=15,586.36 15,586.36*.14*...

**chemistry**

For the following reaction in acidic solution. Cr2O7^2- + I- ---> Cr^3+ + IO3- Give the total balanced net ionic equation.

**chemistry**

For the following reaction in acidic solution. Cr2O7^2- + I- ---> Cr^3+ + IO3- give the balanced half reduction reaction. Indicate the oxidizing species.

**chemistry**

Sorry the equation is: Cr2O7^2- + I- ---> Cr^3+ + IO3^- (dont sure the balanced equation)

**chemistry**

0.125g of sodium dichromate is to be reacted wtih 0.025M potassium iodide. How many mLs of the potassium iodide solution will be needed. (Use your balanced equations above.)

**chemistry**

Using your 0.0100M oxalate solution and only the equipment and supplies listed below, describe how to prepare a 0.00025M solution of oxalate. Note, you are not allowed to add volumes with pipettes. (example, if you want 20mLs, you can not use a 10mL + 10mL addition as this ...

**physics**

a flask contains helium gas at 11k. the flask is thermally isolated and the gas is allowed to escape slowly through a narrow tube until the pressure within the flask is 0.98 atm and the temperature is 4.2K. if the gas is ideal, find the initial pressure for the flask to be ...

**science**

what is the probability of a right handed person and a left handed person having a heterozygous child? homozygous dominant? homozygous recessive?

**Probability & Statistics**

Charmaine is looking at the rental car prices for Get You There Rental Car Company. The cost is based on how many miles you plan to drive the rental car. Use the list of rental prices to answer the questions 1- 5. Miles Cost 200 $80 600 $120 1000 $160 1400 $200 1800 $320 1) ...

**Probability & Statistics**

Charmaine is looking at the rental car prices for Get You There Rental Car Company. The cost is based on how many miles you plan to drive the rental car. Use the list of rental prices to answer the questions 1- 5. Miles Cost 200 $80 600 $120 1000 $160 1400 $200 1800 $320 1) ...

**English**

THank you SO much

**English**

im using APA and also if i site my sources in my essay do i use parenthesis or quotation marks? And also if i take something from a website word to word do i use quotation around it? or parenthesis?

**English**

its not a question its more like a four page essay. Can you tell me if i'm using a website how should i reference it? should i write the name of the website or the topic?

**English**

Ms. Sue can i please have your email address I really need your help with my essay

**Math**

A container holds 12 red marbles, 10 blue marbles, and 14 green marbles. You will randomly select two marbles without replacement. -Fill in the probabilities on each branch of the tree diagram. Use the boxes with the fraction bars already provided. -Use the tree diagram to ...

**LA**

D .

**LA**

jerry came to school incognito like superman in his clark kent glasses question; as used in the passage what does incogonito mean ? a. strength b. in a cape c. dressed formally D. disguised i pic C or D am i cerrect?

**lA**

yes im sorry i have misspelled that word

**lA**

the havasupai are ararian; they live off the summer crops they grow in the valley. .. .. what is the meaning of the word agrariam as is used in the sentence? A. farming the land to survive b . hunting south of the canyon c . herding animals such as deer d . making a livelihood...

**science**

Calculate the de Broglie wavelength of a 0.44 kg ball moving with a constant velocity of 26 m/s (about 60 mi/h).

**Intermidete Algebra**

A rectangle's length is twice its width and it's perimeter is 48m. Find the dimensions.

**math**

@steve Why is the base of the box 16-2x by 10-2x (where did the 2x come from?)

**math**

An open box is made from a rectangular piece of cardboard measuring 16 cm by 10cm. Four equal squares are to be cut from each corner and flaps folded up. Find the length of the side of the square which makes the volume of the box as large as possible. Find the largest volume

**Chemistry**

20 ml of 0.1 M acetic acid was mixed with 25 ml of 0.1 M Sodium Acetate. The pH was measured to be 4.43. 5 ml of 0.1 M Sodium Hydroxide was added to the buffer and the pH was measured to be 4.60. Calculate the pH of the buffer before and after the addition of NaOH.

**Chemistry**

1 g of acid was mixed with 120 ml of distilled water and the solution was filtered into a clean dry beaker. A 25 ml aliquot of this solution was titrated with 0.1120 M NaOH. The pH of the acid was recorded to be 4.42. Calculate the initial concentration of the weak acid and ...

**Math**

A gasoline tank contains 500 liters of gasoline. By the end of each day, 70% of the gasoline remains. When will there be less than 100 liters in the tank?

**Math**

Find the first five terms of the sequence using the recursive rule: a1 = 2/3, and An = 5a N-1

**Chemistry**

A 30.0-ml sample of 0.165 M propanoic acid is titrated with 0.300 M KOH. What is the pH at 5 ml of added base, at 10 ml of added base?

**chemistry**

Calculate whether or not a precipitate will form if 1.40 mL of 0.62 M NH3 are added to 4.4 L of 1.0 10-3 M FeSO4.

**11**

A ball is dropped vertically from height of 30 meters after bounces.The ball reaches a max height to 60% of height of the previous bounce. What are the terms of the sequence. What is the height to the nearest tenth of a meter of the ball after the tenth bounces?

**Management Science**

Riverside oil company in eastern Kentucky produces 3 different grades of gasoline. They are regular, premium, and supreme grades. Each barrel of regular grade sells for $82 while premium grade sells for $88 per barrel and supreme grade sells for $89 per barrel. Petroleum ...

**Physics**

A roller coaster cart travelling due north at 20m/s that turns left during an interval of 4.0s without changing speed. Find the average acceleration. I understand the mathematics behind it (using pythagoras's theorem to find velocity and the formula acceleration = velocity...

**math**

5 radical 3

**math**

Express 4 radical 75

**math**

thanks

**math**

The bases on a baseball diamond are 90 feet apart. How far is it from home plate to second base? Please explain

**Chemistry**

The pH of a 1 .00 x 10-2 M solution of cyanic acid(HOCN) is 2.77 at 25 degrees. Calculate Ka and pKa for HOCN from this result.

**MATH**

A ladder is 25 ft long. The ladder needs to reach to a window that is 24 ft above the ground. How far away from the building should the bottom of the ladder be placed? Please show work.

**Chemistry**

Thank you so much

**Chemistry**

Iodine is mainly found in water in the trioxide ion, I3 which is formed by the combination of molecular iodine, I2 and Iodide, I-, according to the equation: I2(aq) +I-(aq) <----> I3(aq) QUESTION: how does the system in the equilibrium seem to respond to the changes ...

**Ms. Sue Please HELP**

Adam is 5 years younger than Eve. In 1 year, Eve will be three times as old as Adam was 4 years ago. Find their ages now.

**Math**

6 and8

**Math**

yes thanks

**Math**

sorry

**Math**

Barry is 8 years older than his sister. In 3 years, he will be twice as old as she will be then. How old is each now? Please show work! I don't understand.

**American Goverment**

What European country was England's primary rival in North America? In which colonies did the citizens have the most power over their own affairs? About how long after the conflict between Britain and the colonies broke into open warfare was the Declaration of Independence...

**Math**

solve for x in the interval [0,2π): 3csc^2(5x)=-4

**math**

For a fundrasier, the Best Buddies club sold t-shirts. The adult shirts were $15 per shirt and the youth shirts were $12 per shirt, and they made a total of $330 on the shirts. If they sold a total of 26 shirts, how many of each did they sell? I don't understand this, so ...

**Physics**

A 0.03-kg bullet is fired vertically at 200m/s into a 0.15-kg baseball that is initially at rest. The bullet lodges in the baseball and, after the collision, the baseball/bullet rise to a height of 37m. (a). What was the speed of the baseball/bullet right after the collision...

**Math**

At a concession stand, popcorn costs $1.10 and nachos cost $2.35. One day, the receipts for a total of 172 popcorn and nachos were $294.20. How many popcorns were sold. Please show work! I don't understand

**Math**

15 😝

**Chemistry**

calculate the enthalpy change for: (enthalpy of formation of aqueous sodium hydroxide is -469.60 kJ/mol. enthalpy of formation of liquid water is -285.8 kJ/mol) 2Na + 2H2O = 2 NaOH + H2

**chemistry**

a weather balloon partially filled w/ 33.5 L of helium @ 18 deg C & .95 atm. what volume will helium occupy @ -23 deg C w/ a pressure of 3 x 10 to the -3 atm?

**chemistry**

calculate the # of moles of oxygen in 2 L @ 24 deg C & 750 torr

**Chemistry**

# of moles of oxygen in 2 L @ 24 deg C & 750 torr?

**chem hwk help!**

Given the following reaction: 3 CaCl2 + 2 H3PO4 Ca3(PO4)2 + 6 HCl How many grams of H3PO4 are needed to react completely with 1.837 g of CaCl2? I don't understand at all

**chemchemchem**

thad do you know how to do #13?

**chemchemchem**

yes! thank you it worked!

**ALGEBRA 1 PLEASE HELP! I DONT UNDERSTAND**

In basketball you score 2 points for a field goal and 1 point for a free throw. Suppose that you have scored at least 3 points in every game this season, and have a season high score of 15 points in one game. How many field goals and free throws could you have made in any one ...

**math (algerba 1) Please help!**

In basketball you score 2 points for a field goal and 1 point for a free throw. Suppose that you have scored at least 3 points in every game this season, and have a season high score of 15 points in one game. How many field goals and free throws could you have made in any one ...

**science/evolution**

what exactly is the unity of life?

**science**

what is the unity of life? if asked to explain two examples could it be a human and a chimp or would the two examples be DNA and RNA?

**biology**

what is the importance of islands in the study of evolution?

**Stat**

Please help with this problem, not sure calculate it. Consider the standard normal distribution and find P(-1.5 < Z < 2.35).

**Math**

49 bishhh

**Physics**

A kickoff sends a football with an initial velocity of 25 m/s at an angle of 50 degrees above the horizontal. a) find the x and y components of the velocity b) find the time the ball is in the air c) find the horizontal distance the ball travels before hitting the ground d) ...

**Physics**

a 254-kg crate is pushed horizontally with a force of 740 N. if the coefficient of friction is .20, calculate the acceleration of the crate

**Geometry**

it is not a right triangle. the easiest way i determine is if they are factors of 3,4 and 5

**chemistry**

The air exhaled by an average human being might have the following typical combustion, expressed in terms of partial pressures: N2 = 569torr; O2 = 116 torr; CO2 =28 torr; water vapor = 47 torr. what are the mole fractions of each?

**Physics**

A 50-kg satellite circles the Earth in an orbit with a period of 120 min. What minimum energy is required to change the orbit to another circular orbit with a period of 180 min? (Earth: radius = 6.4 106 m, mass = 6.0 1024 kg)

**algebra**

Does 6+5x=44

**Chemistry**

I have one more question, why is the volume of NaCl 0.05 L when we are calculating the mols and 0.1 L when we are calculating mass?

**Chemistry**

Thankyou so much for all the help and the explanation and your time.

**Chemistry**

Originally the enthalpy is negative then how does it become postive and I have followed the steps and I came up 47.36 J/g degrees C. Also I don't understand why enthalpy is q if you could please explain that, and thankyou so much.

**Chemistry**

yes dt is delta T and i think it is the specific heat capacity of NaCl but im not sure

**Chemistry**

Naoh (aq) + HCl (aq) --> NaCl (aq) + H2O (l) Using the dT determined in part 1, calculate the heat capacity of the calorimeter. Enthalpy of reaction= -58.3 kj/mol, Cs (NaCl = 3.91j/g C)density of 1 M NaCl = 1.037g/mL. dT= 12.88 degrees Celcius.50 mL of 2.00 M HCl and 50 ml ...

**Chemistry**

50 mL of 2.00 M HCl and 50 ml of 2.05 M NaOH were used

**Chemistry**

Naoh (aq) + HCl (aq) --> NaCl (aq) + H2O (l) Using the dT determined in part 1, calculate the heat capacity of the calorimeter. Enthalpy of reaction= -58.3 kj/mol, Cs (NaCl = 3.91j/g C)density of 1 M NaCl = 1.037g/mL. dT= 12.88 degrees Celcius.

**Physics**

Consider a stainless steel annular disk with an outer radius 68mm and inner radius7.4mm. The mass of the disk is 1349 grams. The stainless steel annular disk is allowed to rotate on a frictionless table with the rotation axis at its center. The disk has a small cylinder ...

**Physics**

Consider a stainless steel annular disk with an outer radius 68mm and inner radius7.4mm. The mass of the disk is 1349 grams. The stainless steel annular disk is allowed to rotate on a frictionless table with the rotation axis at its center. The disk has a small cylinder ...

**Chemistry**

A sample of the compound prepared in this experiment, weighing .1021g, is dissolved in HNO3 and diluted to a volume of 100mL. A 10mL aliquot of that solution is mixed with 10mL 6 M NH3. The [Cu(NH3)4 2+] in the resulting solution is 5.16x10^-3 M. How many moles of Cu were in ...

**Physics**

The drawing shows a jet engine suspended beneath the wing of an airplane. The weight W of the engine is 12000 N and acts as shown in the drawing. In flight the engine produces a thrust T of 54200 N that is parallel to the ground. The rotational axis in the drawing is ...

**Math**

How many integers bewteen 200 and 500 inclusive leave a remainder 1 when divided by 7 and a remainder 3 when divided by 4? Find the smallest positive integer that leaves a remainder 5 when divided by 7, a remainder 6 when divided by 11, and a remainder 4 when divided by 13.

**Math**

Which Statements of congruence are true and which are false and why? 177 _= 17 871 _= 713 1322 _= 5294 5141 _= 8353 13944 _= 8919 67 x 73 _= 1 x 3 17 x 18 x 19 x 20 _= 4! 83 (144 power) _= 15 (144 power) Their not equals signs...they are three lines on top of one another.

**Stoichiometry**

A gas mixture at 27 C and 750 torr contains acetone vapor with 70% saturation. Calculate the temperature to which the gas must be cooled, at constant pressure to condense 40% of the acetone.

**Math**

Sue drives 36 miles to the fair. Every 4 miles, she sees a sign to the fair. . How many signs will she see on her trip in all?

**Chemistry**

calculate the volume of a rectangular prism with a length of 5.6 , a width of 2.1 , and a height of 6.6 .

**Chemistry**

Suppose you are asked to find the area of a rectangle that is 2.1- wide by 5.6- long. Your calculator answer would be 11.76 . Now suppose you are asked to enter the answer to two significant figures. (Note that if you do not round your answer to two significant figures, your ...

**Physics**

In a World Cup soccer match, Juan is running due north toward the goal with a speed of 7.70 relative to the ground. A teammate passes the ball to him. The ball has a speed of 13.3 and is moving in a direction of 30.5 east of north, relative to the ground. a) what is the ...

**math**

Every year there is a race to the top of the empire state building. In 1993 the winner got to the top in 10 minutes, 18 seconds. how many stairs did the winner go up per second, rounded to the nearest whole number

**Math**

What is the doubling time of prices which are increasing by 5 percent per year?

**Precalculus**

What is the doubling time of prices which are increasing by 5 percent per year?

**Math**

The half-life of radioactive strontium-90 is approximately 32 years. In 1961, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 8 percent of the original...

**Physics**

12

**math**

Show that f and g are inverse functions algebraically. f(x)=x^3/2 g(x)=3 cuberoot 2x My work so far: (3sqrt2x)^3 ------------ 2 I need help on the numeral part of the expression

**pre-calc**

Show that f and g are inverse functions algebraically. f(x)=x^3/2 g(x)=3 cuberoot 2x My work so far: (3sqrt2x)^3 ------------ 2 I need help on the numeral part of the expression