Posts by Jamie

Total # Posts: 1,115

AP Chemistry
In the reaction below, 17 g of H2S with excess O2 produced 10 g of sulfur. 2 H2S + O2 ? 2 S + 2 H2O . What is the percent yield of sulfur? Answer in units of %.

AP Chemistry
Got it! Thank you :)

AP Chemistry
The reaction of 8 grams of fluorine with excess chlorine produced 6.4 grams of ClF3. What percent yield of ClF3 was obtained? Answer in units of %

AP Chemistry
Thank you!!

Chemistry - Rates
For a particular reaction, the rate constant is 2.32???10?3 M/s at 185°C and 3.70???10?3 M/s at 235°C. What is the activation energy for this reaction? _______ kJ/mol

Chemisty - Colligative properties/freezing point
QUESTION: How do you determine the molar mass of the unknown, nonelectrolyte compound for each trial? This is for a lab. My data is: freezing point of solvent (water): -0.58 freezing point of unknown: -0.93 Mass of solvent (water): 19 ml Mass of unknown: 1.045g I know the ...

social studies
yes, the calendar ! Thank you, Ms.Sue

social studies
Which of the following was an achievement of the Mayas? 1) a system of canals in their main city? 2) the city of Tenochtitlan 3) a calendar 4) a strong army I think it is 1 but not sure. Thanks for your help.

Chemistry - Colligative properties/freezing point
I need help on my lab. I think I have all the data and steps right, but my results aren't making sense: Feezing point of water: -0.58 C Freezing point of Unknown: -0.93 C Freezing point depressions: 0.34 C Mass of unknown: 1.045 g, mass of solvent (water): 19 ml, Water=1....

Chemistry
The rate constant for the decomposition of acetaldehyde, CH3CHO, to methane, CH4, and carbon monoxide, CO, in the gas phase is 1.59???10?2 L/mol/s at 711 K and 3.63 L/mol/s at 855 K. Determine the activation energy (in kJ/mol) for this decomposition. ______ kJ/mo

Chemistry
At 500 K in the presence of a copper surface, ethanol decomposes according to the following equation. C2H5OH(g) CH3CHO(g) + H2(g) The pressure of C2H5OH was measured as a function of time and the following data were obtained. Time (s) PC2H5OH (torr) 0 250. 100. 237 200. 224 ...

social studies
The port cities of East Africa traded with ? 1)China,India, and Soutwest Asia 2)Songhai 3)Europe and the Americas 4)Portugal I think number 1. I have read the text several times but still not sure. Thanks for your help.

Math. Please help!!
The "perpendicular bisector" of the line segment \overline{AB}(The backslash then over line with the {AB} means that there's a line over AB) is the line that passes through the midpoint of \overline{AB} and is perpendicular to \overline{AB}.

Algebra A
The "perpendicular bisector" of the line segment \overline{AB}(The backslash then over line with the {AB} means that there's a line over AB) is the line that passes through the midpoint of \overline{AB} and is perpendicular to \overline{AB}.

Algebra A (1510)
Yes, I do.

Algebra A (1510)
Also how do you find slope?

Algebra A (1510)
Thanks for the help!

Algebra A (1510)
The "perpendicular bisector" of the line segment $\overline{AB}$ is the line that passes through the midpoint of $\overline{AB}$ and is perpendicular to $\overline{AB}$. The equation of the perpendicular bisector of the line segment joining the points (1,2) and (-5,...

College Algebra
I hope it makes sense now ^-^

College Algebra
You would treat the greater than or equal to sign like an equation. So, you would subtract 1/2 from each side so y would be greater than or equal to 1/6. In interval notation it would be: [1/6, inf)

Science
thank you

Science
2. Which of the following describes a relationship between science and society? A: Scientific discoveries can impact human life; therefore, society must remain scientifically literate. B: Scientific discoveries rarely impact human life; therefore, it is not necessary for ...

social studies
Mecca lay on a trade route on the edge of the desert that takes up most of? 1)the Red Sea 2)Syria 3)the Kabah 4)the Arabian Peninsula I think # 4 is correct even though, today most of this area is Syria. Thanks

Spanish 1
Which of the following geographical locations share borders with SPAIN? 1)Portugal, France, Atlantic Ocean 2)France, England, Pacific Ocean 3) Italy, France, Mediterranean Sea I think #1 Thank you

Calculus II
Find the derivative of 5^(x^3+x) I know the answer, it's: 5^(x^3+x)*ln(5)*(3x^2+ 1) I just need some help on how to derive that. What rule is at work here? where did the ln come from?

Economics - Finance
Your first baby was born yesterday and is healthy and strong. To guard against your premature death, you want to purchase a life insurance policy that will replace $58,000 of your annual income until your child is 20 years old. How much life insurance should you purchase, if ...

Chemistry
A chemist makes a solution of K2SO4 by dissolving 21.7 g K2SO4 in water to make 100.0 mL of solution. What is the concentration of SO42? ions in the solution? Assume that K2SO4 is the only solute in the solution. The molar mass of K2SO4 is 174.27 g/mol.

Math
Thank you. The answer is 34%?

Math
THe Acme Industrial Tech College has fallen on hard times. Last year its enrollment dropped by 20%, and this year enrollement dropped another 15% from last years. Next year the college expected to have 50% of this years enrollment. What percent of enrollment can be expected to...

Chemistry - Stoichiometry/gases
Ah, Okay. Thanks!

Chemistry - Stoichiometry/gases
When 2.38 g of methane burns in oxygen, 119 kJ of heat is produced. What is the enthalpy of combustion (in kJ) per mole of methane under these conditions? Your answer will be in kJ/mol. the Molar Mass of methane is 16.04, so I did 2.38g/16.04=0.14838 mol Then I did 119 kj/0....

Calculus 2
Determine the first three terms of the power series representations for the following functions: a) 2/(1+x)^3 b) 1/1+x^2 c) ln(1+x)

Calculus 2 - Indeterminant forms
lim (2^x-3^x)/(cos(x)-1) x->0 The answer the book has for this is "diverges." I know I'm supposed to use L'Hospitals' rule, but I'm not sure how. Can you walk me through the steps?

Chemistry
Ah, Okay. Thank you so much for your help. I'll be sure to pay more attention to that in the future.

Chemistry
Huh... that's weird then. I ended plugging this in: ln(56.1/101.325)=(29820/8.314)((1/T2)-(1/380.85)) And solved -0.59119=(29820/8.314)((1/T2)-(1/380.85)) to get 349.93. Then I subtracted 273.15 to get 76.78 C.

Chemistry
Okay, I wasn't converting kPa to atm. That was the problem. I got 76.8 C, and that was the right answer. Thank you for your help!

Chemistry
yeah, I did that. I've got P1=65.1 P2=56.1 T1=330.85 K T2=? H=29,830 j/mol Plugging this in, I got 40.6. But my HW system isn't accepting it.

Chemistry
At 57.7°C, the vapor pressure of CCl4 is 56.1 kPa, and its enthalpy of vaporization is 29.82 kJ/mol. Use this information to estimate the normal boiling point (in °C) for CCl4.

Chemistry - thermochemistry
Hydrogen gas (H2) is generated by the following reaction. Ca(s) + 2 HCl(aq) ? CaCl2(aq) + H2(g); ?H = ?542.7 kJ/mol When this reaction takes place in a cylinder (fitted with a piston) containing 1.000 mol Ca(s), 542.7 kJ heat is lost to the surroundings. Because a gas is ...

Chemistry - Kinetic Molecular Theory
I found an online calculator to check the work, and it gave me 1.086 g/L, which the HW system accepted. I don't really understand what I did wrong... It seems to depend on how I enter it into my calculator: (0.97763*23.036)/(0.08205746*285.35) gives me 1.086 (0.97763*23....

Chemistry - Kinetic Molecular Theory
Question: What is the density (in g/L) of ethyne gas at 743 torr and 12.2°C? The unrounded molar mass of ethyne is 26.036 g/mol. I did some unit conversions, so 743 torr=0.97763 atm and 12.2°C=285.35°K I used the equation d=PMr/RT and I plugged in values to get d=(...

Economics - Formula Help
Instead of spending the $50 a month you receive, you decided to invest it in your money market account at your bank. Assuming you will earn an average of 5% each year and inflation is forecasted to 2.5% a year, how much have you effectively earned after ten years? (Hint: must...

Economics
If there was a baby boom of Oompa Loompas ready to work for free, what will happen to the Willy Wonka chocolate market? In particular: Has this affected supply or demand of Willy Wonka Chocolate? What has happened to the price of Willy Wonka chocolate? Please describe the ...

Chemistry
If the maximum velocity v of an electron in copper wire is about 2.0x10^8 cm/s, with an uncertainty ? 1%, how accurately can the electron's position be determined? In other words, what is the uncertainty in the position of the electron (in meters)?

Math Probability
A number cube is rolled 450 times. The number 3 comes up 67 times. What is the theoretical and experimental probability of rolling a 3 ? I think the answer is 2/9 but not sure of the process. Can someone explain to me. Sorry to be so much trouble. Thanks

Math Probability
You mix the letters M,A,T,H,E,M,A,T,I,C,A and L, thoroughly, Without looking , you draw one letter. Find the probability P(A). Write the probability as: A) fraction in simplest form B) a decimal C) a percent there are 3 letter A"s, so my answers are A)1/4 B).25 C) 25% can...

math
From a barrel of colored marbles, you randomly select 5 blue, 2 yellow, 3 red,4 green, and 2 purple. Find the experimental probability of randomly selecting a marble that is NOT yellow. 1) 9/16 2) 7/8 3) 8/9 4) 3/4 I think 7/8 Thanks.

Chemistry - Significant Figures
Suppose it takes 35 min for 2.4 g of sugar to completely react with another reagent we added to the flask. What would the reaction rate be? Calculate to the correct number of significant figures.

math
Thanks, I went a little foggy.

math
A single, standard number cube is tossed. What is the probability of getting a number greater than 3? 1) 2/3 2) 1/3 3) 1/6 4) 1/2 I think 1/2 Thanks

math
C is the correct answer...thanks for helping me.

math
A coin is flipped 3 times. How does the P (H,H,H) compare to P(H,T,H) ? 1)P (H,H,H) is greater than P(H,T,H) 2) P(H,T,H) is greater than P(H,H,H) 3)The probabilities are the same 4)There is no way to tell with the info given I think #4 is correct...can you advise? Thanks

math
A coin is tossed and a number cube is rolled. What is P(heads, a number less than 5)? 1) 1/3 2) 5/12 3) 2/3 4) 5/6 I think #2...can you check?

Math Probability
The probability of having a winning raffle ticket is 20%. If you bought 50 tickets, how many wining tickets should you expect to have? 1)3 tickets 2)8 tickets 3)10 tickets I think #3 Thanks

Math Probability
You roll a number cube 20 times. It lands on 2 five times. What is the experimental probability of rolling a 2? 1}40% 2)10% 3)25% 4)17% I think #3 Thanks

math
Which of the following is a certain event? 1) rolling a composite number on a number cube 2)rolling a number greater than 1 on a number cube 3)rolling an odd or even number on a number cube 4)rolling an odd or even number greater than 7 I think # 3 Thanks for your hrlp

Science
A kitchen ceiling light has five lightbulbs on it. When one of the lights goes out, the other four will stay lit. This is an example of a series circuit. True or False I think FALSE because a series circuit would make them all go out.

Science
Electric charges that are different? 1)attract each other 2)repel each other 3)exist in pairs 4)do not interact I think #1 Thanks

Art
Which of the following items is the best example of functional art? 1)stones 2)a vase 3)paper clip 4)rag I think #1 Thanks

Health
Thank you for the website, after reading it, I will go with the #1 answer. Like my book, it also says malnutrition, organ damage and total dependence on the drug.

Health
Which statement is true about stage 3 of alcoholism? 1)malnutrition and liver and brain damage often occur 2)Teenagers go through this stage very slowly 3)The drinker becomes totally dependent on the drug 4)The drinker begins trying to escape the everyday stressors. I think #1...

English
Thanks, but I did check the meaning of careening( swiftly and uncontrollable) but 3 of the answers were so close, I could not decide. I have changed my answer to #2 Thanks for being so nice.

English
The truck was "careening" around the sharp curves of the road as it made its way down the steep mountainside. Which is best definition of the word "careening"? 1)spinning wildly 2)hustling rapidly 3)lurching dangerously 4)wandering aimlessly I think #1 ...

Art
An Art critic writes the following comment about the seventeenth century painting. "The Dutch is a master of light and composition." This statement is an example of what stage of critique? 1)describe 2)analyze 3)critique 4)judge I think #4 The reason I think this is ...

social studies
Agricultural activities in the Pampas most supports? 1) cacao farming 2) coffee farming 3) silver mining 4) cattle ranching I think #4 Thanks

ART
Which object would be the best addition to a collection of writing instruments that are unique to the twentieth century? 1) a pencil 2)a computer 3)a crayon 4)a calligraphy pen I think#2 Thanks for your help

English
Choose the meaning of "carvorted" in the sentence. The children carvorted about when the teacher played their favorite music. 1)mingled 2)frolicked 3)tumbled 4)waved my answer is #2....thanks for your help.

Science
One light bulb in a string of lights goes out. This causes all the other lights in the string to also go out. This is an example of a?? 1) resistor 2)parallel circuit 3)closed circuit 4)series circuit I think #4. Thanks in advance for your help.

English
So I already post a question however I forgot to write the definition of "conventional phrases" so here it is:Meaning beyond literal meaning Ex. – if a character is making his/her bed or making the bed narrow, the speaker is preparing for death My questions are ...

English
I need help finding conventional phrases in the Ballad of Birmingham by Dudley Randall that could add to the mood of suspense and tragedy.

math
Identify the dependent variable in the relationship. A person burns a total of "c" calories by walking "m" miles. 1)calories 2)miles 3)neither "c" calories or "m" miles 4) both "c" calories and "m" miles I THINK #2, ...

SS
The monumental cities of the Incas demonstrated their? 1)extensive trade networks 2)high level of organization 3)interest in astronomy 4)dependence on farming I THINK #2 Thanks in advance for your help.

English
Thanks, Ms. Sue # 2

English
What is the prepositional phrase in the sentence? Put the lasagna in the oven tonight if you don't mind. 1) put the lasagna 2) in the over 3) the oven tonight 4) if you don't mind I think #1

SS
If you were to move to the PAMPAS, where would you most likely find a job? 1)in the silver mines 2)on a cattle ranch 3)on a coffee plantation 4)in the fisheries I think #2

SS
How does elevation impact ecosystems in SOUTH AMERICA? 1)farmers can grow different crops at different elevations. 2)plants do not grow above tree lines 3) animals cannot live in higher elevations 4)humans settle only in the lowest elevations I THINK #1

Science
Which of the following describes an example of land reclamation? 1) after an area is mined for copper, the soil is replaced and new plants are planted. 2)after a forest is clear-cut, desertification occurs. 3)after a forest is clear-cut, it is mined for copper 4)after an area ...

SS
Which of the following is a source of photochemical smog? 1)fossil fuels 2)wind energy 3)biomass fuels 4)nuclear energy I THINK 4

Science
Which of these is an example of a biomass fuel? 1) oil 2) natural gas 3) wood 4) coal I think #3

ART
A community artist creates a mural of the surrounding farm country. far-off hills, trees, and buildings are slightly blurry and lighter in color than the objects in the foreground. What type of perspective did the artist use in the painting? A:linear perspective B:atmospheric ...

ART
Grieving and surrounding the body of a deceased loved one is an example of what art? 1)a cultural rule 2)a community norm 3)an uncommon ritual 4)a community job I think #1

math
How do I find vertex, focus and directrix for the following functions? y^2?16y=12x?8^2 x^2+16x=4y?24 (x?2)^2=12(y?2)

Calculus
Write the following function as the sum of an odd and an even function. Then calculate the integral over the given interval using the properties of odd and even functions. (x-1)^3, I=[-1,1]

french
true

Statistics
Could anyone help me out with the following problem? Identify the consequences (i.e. increase, decrease, or none) that the following procedures are likely to have on both bias and sampling error in an experimental study. A) Assigning treatments to subjects alphabetically, not ...

math
Find the product.11X(-3)X(-5) equals. 1) -165 2)-28 3) 28 4) 165 I think 4 Thanks

math
Which of the following could be represented by -8? 1) a drop of 8 meters 2) 8 T-shirts 3) sea level in 8 places of the world 4) 8 degrees C above 0 I think #1 Thanks

social studies
What circumstance had the most direct impact on European colonization of Caribbean South America? 1) the slave trade in Africa 2) the fur trade n Europe 3) piracy in the Caribbean Sea 4) rumors of gold in El Dorado I think 4 but not sure Thanks for your help

social studies
What geographic features lies east of the Andes Mountains? 1) saltwater grasses 2)active volcanos 3)llanos grasslands 4)mangrove swamps I think 3 Thanks

History
According to their definitions, I would think C (Laissez-faire) is the best option.

social studies
Areas of Mexico that can support agriculture are most affected by variations in ? 1) altitude 2) longitude 3) attitude 4) animal species I think altitude

Grade 11 Math
A uniform-width boardwalk is built around the inside edge of a rectangular parkland that is 30 m by 5 m. If the boardwalk takes up 20% of the lot, how wide is the boardwalk to the nearest centimetre? I know that the total area= 150m^2 boardwalk area= 30m^2 and the parkway area...

english
What are the literary devices used here? "I am frightened: I dare think this way no more. This way lies the abyss. It is not now the time but I will not lose these thoughts, I will keep them, shut them away until the war is ended. My heart beats fast: this is the aim, the...

math
A flagpole at right angle to the horizontal is located on a slope that makes an angle of 12? with the horizontal. The pole's shadow is 16 meters long and points directly down the slope. The angle of elevation from the tip of the shadow to the sun is 20?. What is the height...

Please Help
(?6)?(a+2b?3c?4d)?(?2)?(?4a?3b+2c+d)

Math
(?5)?(3b?2a)?6(a+2b)

math
Thanks

math
callum wins £300 in a raffle. he gives 5% to charity. he saves 2/5 of the £300.he uses the rest of the money to buy clothes. work out how much of the money callum uses to buy clothes./ I tried this question before in a test we got given the test back and were told ...

Chemistry
Does every neutral helium atom in the universe have the same set of absorption lines as every other neutral helium atom (with the same atomic mass)?

Chemistry
oops sorry

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