# Posts by Katy

Total # Posts: 453

**Chemistry**

Calculate the solubility of ZnCO3 in a buffer solution with a pH of 9.83 and Ksp of 1.2x10^-10

**Chemistry**

Calculate the ZnCO3 in a buffer solution with a pH of 9.83

**Math - Calculus**

Show that if f(x) is continuous and u(x) and v(x) are differentiable functions, then: d/dx ?_v(x)^u(x) f(t)dt=u'(x)f(u(x))-v'(x)f(v(x))

**Calculus - Riemann Sum help**

How do I figure out the upper and lower bounds for a riemann sum? This question I'm working on tells me to assume: ?x=2?/n and x_i=i?x and then gives me: n b lim ? sinx_i?x = ?f(x)dx n?? i=1 a Now I'm pretty sure f(x)=sinx, but I don't know how to find a or b. ...

**math**

(a) Make a table of values rounded to two decimal places for the function f(x) = ex for x = 4, 4.5, 5, 5.5, and 6. Then use the table to answer parts (b) and (c). (b) Find the average rate of change of f(x) between x = 4 and x = 6. (Round your answer to two decimal places.)

**Math**

Let f(x)= -3x+4 and g(x)= -x^2 +4x+1. Find and simplify f(-3)

**physics**

A ball is rolled off a table that is 1.25 meters tall and lands on the ground 0.48 meters away. If it took 0.505 seconds for the ball to land, what was the horizontal velocity of the ball? Record your answer to the nearest hundreth m/s (You do not need include units)

**math asap**

Solve the proportion using cross products. 8/20 = k/110 (A)99*^* (B)122 (C)3.3 (D)2.9 Am I correct? please asap

**Algebra**

less than or equal to*

**Algebra**

A department store is offering a coupon for 26% off for any purchases over $100. How much would you spend for a $100 purchase? You would spend $____. Construct a formula a piecewise functiom for the actual cost, C, of the purchase as a function of the original purchase price, ...

**pre algebra**

Beth's savings account has $100 to start. She deposited $12 Monday, withdrew $50 Tuesday, and deposited $30 on Friday. What is her total savings now?

**PreCalc**

As you ride a bicycle, the distance between your foot and the pavement varies sinusoidally with the horizontal distance the bicycle has gone. Suppose that you start with your right foot somewhere between a high point and a low point, and push down. When you have gone 7 meters...

**PreCalc**

The temperature T(t) varies sinusoidally on a certain day in December. The minimum temperature is 35 degrees Fahrenheit at midnight. The maximum temperature is 50 degrees Fahrenheit at noon. Let t be the number of hours since midnight (t=o at midnight). a.) Sketch and label a ...

**art help please**

I had to do the same project. I took the top part off of pens, the part the u click in and out, and slipped them on toothpicks. I attached the toothpicks to the wooden base. Whenever I wanted to "Tune the guitar" I would turn the pen piece, and stick a glue dot ...

**Math**

mike can drive his car 33 miles with one gallon of gas does he need to drive 15000 miles?

**Maths**

Is this statement true? Give an example to support your answer. "If two numbers are divisible by another number then their difference is also divisible by that number". I think that its like this: 3 and 4 is divisible by 12 then 4-3=1 so the answer is no?

**Social studies last one :)**

Thanks again Mrs. Sue and I got a 100!

**Social studies last one :)**

What is likely a major of weakness of empires? They lack recourses. They conduct far-flung trade. They make enemies. This one maybe A. They have superior weapons.

**Social studies**

Thank you!

**Social studies**

How has Aztec culture survived in Mexico? The Mexican military uses Aztec fighting tactics. Mexico still uses the Aztec calendar. The Mexican people have adopted many Nahuatl words into their language. My choice An Aztec Palace in Mexico city serves as the capital building.

**French**

Hi Page, You need to make sure you add in amounts of the different ingredients. France is on the metric system, so their recipes usually have quantities in grams (g), liters (l), soup spoons (c. a s.), and coffee spoons (c. a c.). Otherwise, here are the changes I would ...

**Curriculum Areas**

Seriously...do it yourself, if you don't want to, just write a for all of them

**math**

Same question on my homework, the answer is 12x8x5, volume is 480.

**english**

a)Lying about where he lives

**Science**

Number 9 is actually is C

**Math**

Sara and Jenny can both do flips in the air. The ratio of the number of flips Sara can do to the number of flips Jenny can do is 3:8. Jenny can do 120 more flips than Sara. If Sara increases the number of her flips by 3 and Jenny decreases the number of her flips by 12, what ...

**math**

php. 30000.00 just multiply the numbers.

**engineering**

any help is greatly appreciated. I am so hopeless now. Water tower problem. The pressure in each house is 250 kPa and the average pressure drop is 50kPa. What should the height of the water tower? Height of the water level in the tower. What is the diameter of the water tower?

**chemistry/engineering**

Wet sugar, containing one-fifth water by mass is conveyed through an evaporator in which 85.0% of the entering water is vaporized. Taking a Basis of 100 kg of feed to the evaporator A barrel of oil contains about 6 million Btu and about 1000 Btu is needed to evaporate one lbm ...

**Geometry**

I still don't get the answer steve? I calculated, but nothing close.

**Geometry**

A circle has a center at (8,2). The point is (3,7) is on the circle. What is the area of the circle to the nearest tenth of a square unit? A. 22.2 B. 44.4 C. 157.1 D. 314.2 (I've been stuck on this question for a while) thanks!!

**geometry**

The endpoints of the diameter of a circle are at (1,2) and (7,-6). What is the circumference of the circle, to the nearest tenth of a unit.

**geometry**

how?

**geometry**

So what would I do after that?

**geometry**

What is the perimeter of rectangle WXYZ, with vertices W(-3,7), X(-5,4), Y(1,0), and Z(3,3) to the nearest unit.

**geometry**

Jenny is building a rectangular garden around a tree in her yard. The southwest corner of the garden will be 2 feet south and 3 feet west of the tree. The northeast corner of the garden will be 1 foot north and 4 feet east of the tree. If jenny paves a path around the garden ...

**math**

Julia spent 1/3 of her money. Then she lost 1/2 of the rest. She now has $10 left. How much did she get for her birthday?

**Finite Math**

Can someone please help me. I am not sure to work the following matrices. If A^4 = -3 4 -4 5 and A^5= 4 -5 5 -6 What is A? Can you show me how you got this? Thank you so much ;)

**ECO 372**

Aggregate demand management policies are designed most directly to?

**Finite Math**

Thanks Steve!! You're a life saver ;) Katy

**Finite Math**

Can someone help me out with this! Thank you in advance :) Frank’s Fruit Stand sells fresh fruit as well as fruit dipped in chocolate and covered with chopped almonds. Each dipped banana requires 6 grams of chocolate and 3 grams of almonds to coat. It takes 6 grams of ...

**BUS 599**

According to double-entry accounting, which of the following is a correct statement regarding transactions?

**analytical chemistry**

DrBob222, it is me again. Continue the question 5mL of a solution A (unknown concentration) was transferred into sic 25mL volumetric flask. The following volumes of a standard solution of A with with a concentration 75ppm were added to the flask: 0mL, 0.5mL, 1mL, 1.5mL, 2mL, ...

**Analytical Chemistry**

DrBob222, thank you for your answer Thanks to your suggestion, my final answer is 7.48447 ppm (unknown concentration) However, I am just wondering why Prof. gave the graph of excitation spectrum of A. One reason I can think of is that I use the highest intensity which is 100 ...

**Analytical Chemistry**

Thank you so much DrBob222. I see what I did wrong. Yes you are right. These number 19.979, 29.986 is intensity from fluorescence (emission) spectra data. The intensity of standard 1 is not 0. It is 9.990. So after correction, the equation I got is y= 6.6656x + 9.9777 and R^2 ...

**Analytical Chemistry**

5mL of a solution A (unknown concentration) was transferred into sic 25mL volumetric flask. The following volumes of a standard solution of A with with a concentration 75ppm were added to the flask: 0mL, 0.5mL, 1mL, 1.5mL, 2mL, and 2.5L. The excitation spectrum and and ...

**chemistry**

Thank you to your suggestion, I have found that path length is 9.7574 mm. But do you know how to write correctly significant number and its uncertainty

**analytical chemistry**

Thank you DrBob222. Can you explain further what you mean by saying "Plotting with data not posted"? I think when I can find the intensity of the unknown, I can plug it in the equation. But my problem is that I don't know how to do?

**analytical chemistry**

There is a b) question that I am stuck too. If a synchronous experiment is to be performed what would be the offset that you would use

**analytical chemistry**

Any help is greatly appreciated 5mL of a solution A (unknown concentration) was transferred into sic 25mL volumetric flask. The following volumes of a standard solution of A with with a concentration 75ppm were added to the flask: 0mL, 0.5mL, 1mL, 1.5mL, 2mL, and 2.5L. The ...

**analytical chemistry**

Consider a general reaction where a ligand L and a metal ion Mn+ form a complex with m number of ligands (L) coordinated to each metal ions. Assume the metal is colorless. The ligand and metal solutions were mixed at molar fractions (and same total molar concentration). The ...

**Science**

Yeah I really don't understand should I pick c or d??

**Science**

Which of the following statements is true? A. There is more water on Earth now than there was millions of years ago. B. There is less water on Earth now than there was millions of years ago. C. There is no way to tell how much water was on Earth millions of years ago. D. There...

**science**

A protostar has a high enough___to become a star. A. volume B. mass C. temperature D. brightness Is the answer B? Thanks in advance

**Civics**

will MsSue just give answer ? cool

**math**

1 and 1/5?

**essay**

thx

**essay**

today

**essay**

Sorry, should have looked at rules and proofread. I didn't know that was like a rule :0

**essay**

I need to come up with an outline for a essay on the differences between the North usa and South? Any ideas? Thanx if u can help

**Math Help**

Hi! I need help with this question. Thanks! Directions: To solve these problems, you need to find the inverses of these 2x2 matrices. a.) D= [-3 -6 6 12] b.) C= [2 1 7 3]

**Math**

440

**Math**

4410+40=4450

**Math**

Answer 4410

**Math**

4000(1+0.05)^2

**Math**

Am suppose to find the compound interest if so could give me the formula

**Math**

Cary puts $400 he earned from mowing lawns in the bank for two years at an interest rate of 5%. What would be the total amount of money that he would have in the bank be at the end of two years. I=prt I=400(0.05)(2) I=40

**Math**

Find the amount of interest Nina's saving account will earn after 3 years if her initial deposit was $900 with an 8% simple interest rate. I=prt I=900(0.08)(3) I=216

**Math**

2%

**Math**

Answer 200

**Math**

I=5000 P=50 R=? T= 6 Answer... About 16 or 17%

**Math**

Dr. Morton puts $5000 in the bank and left it there for 6 months. What simple interest rate she needs to have in order to have made $50 at then end of 6 months?

**Math**

Thank you

**Math**

Monica had a saving a account which paid her an interest rate of 4%. After she had this account for 12 years, she had received $192 in interest. How much money had she put into the account at the beginning of the 12 years? Please help me answer this question step by step

**Math**

Is there any key words that I should remember for each of them

**Math**

How do you know if a word problem question is asking for simple interest or compound interest? P.s. I already know the formula and what both of them mean

**chemistry**

How would you make 1L of a buffer of pH=11 starting with 15g of base, C5H11N:. At you disposal are 1M HCl and 1M NaOH, pH meter, balance, distilled water and glassware. Try to be quantitative in expressing amounts of material that you will use. Given for C5H11NH+ pKa=11.25. ...

**Social studies**

Never mind I got the second question thanks for helping

**Social studies**

How was 13,14,15 amendments before and how is 13,14,14 amendments now like

**Social studies**

I still don't get number 1

**Social studies**

How was 13,14,15 amendments before and how is 13,14,14 amendments after

**Social studies**

My guess on my first question was that if in early years adult citizen has not pay there taxes they are not allow to vote then. My second is basically how was civil war amendment like before and how is it like now

**Social studies**

My first question is "how could a poll tax or a literacy test have been usd to prevent someone from voting? My second question is how was civil war amendments before and after

**Social studies**

How could a poll tax or a literacy test has been used to prevent someone from voting? The Civil war Amendments Before. After

**Social studies**

They needed land

**Social studies**

removal of the Indians beyond the white settlements is approaching to a happy consummation

**Social studies**

Maybe for peace

**Social studies**

president to negotiate with Indian tribes in the Southern United States for their removal to federal territory west of the Mississippi River in exchange for their ancestral homelands. Is this the answer of number 1

**Social studies**

I need some websites that could help me find the answer of all three of them cause I'm a bit of confused

**Social studies**

1.why were American Indians asked to moved? 2. Did the u.s government have the right to ask American Indians to move? 3.what were the benefits of accepting gifts and moving to indian territory.?

**chemistry**

Put the following compounds in order of INCREASING oxidation number of N: N2H4, NO3-1, N2, NH3 ?

**Physics**

A car traveling 85km/h slows down at a constant 0.52m/s2 just by "letting up on the gas." Calculate the distance the car coasts before it stops.

**Math**

The speed of sound in air at sea level at 32 degrees Fahrenheit is 1088 ft/s. If that represents only 22.04% of the speed of sound in ice-cold water, what is the speed of sound in ice-cold water, to the nearest whole number? what i did: 22.04/100 = 32/x i set up this ...

**Math**

Estimate 12 1/2% of 57

**MATH**

ARE THE FOLLOWING EQUATIONS INVERSES? y=x^4-7 and y=∜ x+7

**World History**

The Mongols have a terrible reputation in history as pillagers who destroyed all that met their path. How does this depiction of the Mongols compare with the same people who brought the Pax Mongolia? help please, I don't get it. I have to do this for History, But I don'...

**Math**

83.52 -28.45 ------ 54.57

**prod and oper management**

Hahn Manufacturing purchases a key component of one of its products from a local supplier. The current purchase price is $1,500 per unit. Efforts to standardize parts succeeded to the point that this same component can now be used in five different products. Annual com- ponent...

**chemistry**

Flask A contains 100 milliliters of a solution with a pH of 5. After you add 100 milliliters of a solution from Flask B, the pH rises to 7. What was the pH of the solution in Flask B?

**math**

Simplify the numerical expression below 25-4×5