# Joanie

Most popular questions and responses by Joanie

Calculate the lattice energy of potassium oxide from the following data: Enthalpy of sublimation of potassium: +89.24 kJ/mol Bond energy of oxygen: +498 kJ/mol First ionization energy of potassium: +419 kJ/mol 1st electron affinity of oxygen: -141 kJ/mol

2. ## PreCalculus

Problem: Identify the conic from the equation 13x^2-6(sq.rt.6)xy+7y^2-16=0 I have to choose from the following four answers: hyperbola (angle of rotation 45) hyperbla (angle of rotation 60) ellipse (angle of rotation 90) ellipse (angle of rotation 30) I

3. ## PreCalculus

Given vectors u=7i + 3j and v = -4i + 3j, find 5u-4v in terms of unit vectors. I am just beginning the study of vectors and have this problem. Could someone help? Thanks.

Calculate the lattice energy of potassium oxide from the following data: Enthalpy of sublimation of potassium: +89.24 kJ/mol Bond energy of oxygen: +498 kJ/mol First ionization energy of potassium: +419 kJ/mol 1st electron affinity of oxygen: -141 kJ/mol

5. ## pre calc

An initial investment of \$12,000 is appreciated for 5 years in an account that earns 7% interest, compounded quarterly. Find the amount of money in the account at the end of the period

6. ## chemistry help!!

a gaseous mixture contains 1 mol of O2 and 2 mol of CO2, exerting a total pressure of 1.5 atm. what amount of CH4 must be added to the mixture in order to increase the total pressure to 2 atm. (assume no gas escapes and there is no change in total volume)

7. ## Math

I have to graph the following: 2 = rcos(theta-20 degrees). I put it in the form r = 2/cos(theta-20degrees). Is this correct? I am having trouble with my table of values. I would appreciate your help. Thanks.

8. ## CHEM

a gas bulb is connected to an open end manometer. the pressure in the bulb is .355 torr MORE than atmospheric pressure. If the manometer is filled with mineral oil (density .888 g/cm^3) then what wil be the difference in height between the two sides of the

9. ## PreCalculus

I have to write the equation of a hyperbola whose center is (0,0) and which has a vertical transverse axis. The equations of the asymptotes are 6x+2y=0 and 6x-2y=0. I don't even know where to begin. Could someone help? Thanks.

10. ## PreCalculus

I am having a lot of problems with this linear programming problem. CAn someone help? A farmer buys two varieties of animal feed. Type A contains 9 oz. of oats and 2 oz. of corn per pound. Type B contains 5 oz of oats and 10 oz of corn per pound. The

11. ## Math

Solve 4sin^2x + 4(squareroot of 2)cosx -6 for all real values of x.

12. ## PreCalculus

Write the equation of the conic section x^2+6^2=16 after a rotation of 45 degrees about the origin. I don't know where to begin on this problem. Could you help? Thanks.

13. ## Math

I have two problemson polygonal convex sets which I do not understand. The first: Find the minimum value of f(x,y) = 2x-y+2 for the polygonal convex set determined by this system of inequalities: x is more than or equal to 1 x is less than or equal to 3 y

14. ## algebra

I am to solve ln(x+3)-ln(x-5)=ln7

15. ## Solving inequalities

I have to solve the following inequalities: x^2 + y^2 is less than or equal to 49 y is less than or equal to 3-x^2 I know that these are the equations of a circle and a parable. There should be 3 solutions. However, I am not sure how to solve these

16. ## SCI207

In-place fossil fuel resource statistics can be misleading because

17. ## chemistry

I am having trouble balancing this equation: C6 H12 06 + O2 = C7 H8 + O2 Can you please help? Thanks

18. ## chemistry

I am having trouble balancing this equation: C6 H12 06 + O2 = C7 H8 + O2 Can you please help? Thanks

19. ## Math

Use a metric ruler and a protractor to find 2 a (vector) - 2 b (vector). Then find the magnitude and amplitude of the resultant. When I measured I got 2 for b and 4 for a. The answers I have to choose from are 8cm,41degrees, 9cm,38degrees,6cm,36degrees,

20. ## science

How do you calculate 1 mole of CuSO4 × 5 H2O?

1. ## PHI 103

Weak inductive argument

posted on May 28, 2012
2. ## english

Because she had practiced her presentation so diligently, Jamie

posted on October 3, 2011
3. ## chemistry

Ok so i also was going to ask this question but I THINK i figured it out. remember that mols and pressure are proportional. if 1 mol of O2 gives 2 atm of pressure, then how many mols of a gas gives 1 atm of pressure? (because the total is three, so we just

posted on March 21, 2011
4. ## chemistry

Thanks, I thought so. I will contact my teacher, maybe I copied it down wrong in class. Thanks for your input. Joanie

posted on January 31, 2010
5. ## Language

Hi-- The word "are" in the sentence should be "our." Also, We should be capitalized and there should be a period after backyard.

posted on March 30, 2009
6. ## Math

Thank you for helping.

posted on February 26, 2009
7. ## PreCalculus

Hi drwls-- I have just begun the study of vectors. I am given the answer in multiple choice--The answer you gave me is 7.571. The choices I have are 8cm;41 degrees; 9cm;38degrees;6cm,36degrees, and 4cm,31 degrees. Your answer is closest to 8 cm. Is that

posted on January 30, 2009
8. ## PreCalculus

Dear Reiny, Thank you for helping me. Could you check an answer for me? Use a metric ruler and a protractor to find 2 a (vector) - 2 b (vector). Then find the magnitude and amplitude of the resultant. Vector a is 4 cm and the angle is 60 degrees. Vector b

posted on January 30, 2009
9. ## English

Hi-- "Eight hellish months" would keep the meaning of what you are trying to say. You are putting "hell" in the form of an adjective. Hope this helps.

posted on January 20, 2009
10. ## Math

Thank you for helping me with this problem. Joanie

posted on January 20, 2009