shana

Most popular questions and responses by shana
1. Linear algebra

Suppose that the sequence x0, x1, x2... is defined by x0 = 1, x1 = 5, and xk+2 = 3xk+1+10xk for k≥0. Find a general formula for xk.

2. Chemistry

need help to balance half reaction in basic solution IO3 to I2

3. Chemistry

A 30.00mL sample of 0.150M KOH is titrated with 0.125M HClO4 solution. Calculate the pH after the following volumes of acid have been added: 30.0 mL, 35.0 mL, 36.0 mL, 37.0 mL, 40.0 mL

4. Chemistry

Calcium hydroxide, Ca(OH)2, dissolves in water to the extent of 1.78 g per liter. What is the value of Ksp for Ca(OH)2?

5. Linear algebra

please help :( Bob and Doug play a lot of Ping-Pong, but Doug is a much better player, and wins 90% of their games. To make up for this, if Doug wins a game he will spot Bob five points in their next game. If Doug wins again he will spot Bob ten points the

6. Linear algebra

Find all complex numbers z satisfying z3 = 27i and give your answer as a comma-separated list of values in the form a+bi.

Bob and Doug play a lot of Ping-Pong, but Doug is a much better player, and wins 90% of their games. To make up for this, if Doug wins a game he will spot Bob five points in their next game. If Doug wins again he will spot Bob ten points the next game, and

8. chemistry

Is diphosphorus pentoxide an ionic or a molecular compound? A. Ionic B. Molecular I say B

9. Linear algebra

please help me with this question I have no idea how to solve it, thanks Suppose T is a transformation from ℝ2 to ℝ2. Find the matrix A that induces T if T is rotation by 1/6π.

10. Algebra

I spent hours on this and I still cant figure it out please help me: Let L1 be the line passing through the points Q1=(4, 2, −3) and Q2=(5, 5, −5). Find a value of k so the line L2 passing through the point P1 = P1(3, 7, k) with direction

11. Chemistry

Estimate the solubility of calcium fluoride, CaF2+, (a) in moles per liter and (b) in grams per liter of pure water. CaF2+(s) = Ca2+(aq)+2f-(aq)

12. english

Which literary movement consists of honest and open descriptions the setting and characters? I say B. A. American Modernism B. American Realism C. American Romanticism D. American Transcendentalism

13. Algebra

Let L be the line passing through the point P=(1, −1, −5) with direction vector →d=[−2, −4, 3]T, and let T be the plane defined by −x+y−3z = −1. Find the point Q where L and T intersect.

14. Chemistry

Develop a recipe for 1.00L of pH 4.50 buffer using only 17.4M HC2H3O2 and 3.00M NaOH (and deionized water). Be sure that it can accommodate an addition of at least .50 mol of strong acid or base with a change in pH less than/equal to 1.

15. Chemistry

How do I find delta S of 2 Na(s) + 2H2O(l) -> 2NaOH(aq) +H2(g)? I tried to find it using this.... ^Srxn= 2S(NaOH) - S(H2) -2S(Na) - 2S(H2O) = 2(48.1)-130.7 - 2(51.21) - 2(69.95) = 96.2 - 130.7 - 102.42 - 139.9 = -279.82 Where did I go wrong??

16. Algebra

Find the scalar equation for the plane passing through the points P1=(−3, −5, 5), P2=(1, −6, 6), and P3=(0, −9, 4).

17. math

What is the percent by mass of hydrogen in C3H8? A. 8.0% B. 18.2% C. 80.0% D. 81.8% I say B

18. chem

When NH3 is treated with oxygen gas, the products obtained are N2(g) and H2O(l). If standard enthalpies of formation at 298 K for NH3(g) and H2O(l) are –46.00 kJ/mol and –286.0 kJ/mol respectively, calculate the enthalpy change of the reaction.

19. math

Mercury has a density of 13.6 g/cm^3. What is the specific gravity of mercury? A. 13.6 g B. 13.6 cm C. 13.6 cm^3 D. 13.6

20. statistics

if a data set has mean 70, and standard deviation 5, is 80 asuspect outliner/

21. chemistry

pH = 3.89 calculate concentration of hydronium ion and hydroxide ion in solution.

22. chemistry

When NH3 is treated with oxygen gas, the products obtained are N2(g) and H2O(l). If standard enthalpies of formation at 298 K for NH3(g) and H2O(l) are –46.00 kJ/mol and –286.0 kJ/mol respectively, calculate the enthalpy change of the reaction.

23. MATH

WHAT IS THE SUM OF ALL THE DISTINCT, POSITIVE PRIME FACTORS OF 1260

24. Juvenile Delinquency

Compare the adolescence period in the United States with that of other nations. Compare and contrast any ritualistic (rites of passage) behavior used by both Americans and foreign children. Please re-post and include the answer or response you have come up

25. math

What is one mole of H2O composed of? A. 2 hydrogen atoms and 1 oxygen atom B. 2 × (6.02 × 1023) hydrogen atoms and 6.02 ×1023 oxygen atoms C. 3 atoms of water and 2 oxygen molecules D. one half of a molecule of peroxide I say A

How to solve system of equations 5a=5 6b-3c=15 2a+7c=-5

27. math

In scientific notation, a number is written as the product of a coefficient and the number 10 raised to a power. True False

28. Chemistry

The following reaction is reactant-favored at equilibrium at room temperature. COCl2(g) -> CO(g) + Cl2(g) Will raising or lowering the temperature make it product-favored?

29. chemistry

Which phase of ionic compounds are good electrical conductors because the ions are free to carry electrical current? A. Solid B. Liquid C. Gas D. Crystalline I say B

30. math

If the density of 1.77 grams of gold is 19.3 g/mL, what is the volume

31. College Algebra

Could you please help me with this problem? We are to graph each compound inequality. x ¡Ý -2y and x - 3y < 6

32. Algebra

can anybody help me with this question please? Let L be the line passing through the point P=(5,Â âˆ’5,Â 3) with direction vector â†’d=[1,Â âˆ’3,Â âˆ’2]T. Find the shortest distance d from the point P0=(âˆ’4,Â âˆ’1,Â 4)

33. math

estimate the sales tax and final cost of a book that costs \$12.99 with a sales tax of 6%

34. math

When solving for the percent composition of a given compound, the percent of each element in the compound must be found and reported. True false TRUE

35. math

Solve the following and express the answer in scientific notation:(3.5 x 10^6 / (4.2 x 10^8) A . -8.3 X 10^-3 b. 8.3 X 10^3 c. 8.3 X 10^-2 d. 8.3 X 10^-3 I say A

36. math

Solve the following and express the answer in scientific notation: (5.4 × 10^4) × ( 4.5 × 10^8)

37. english

What word best describes the Realist's and Modernist's perspective on the world? A. Objective B. Passionate C. Subjective D. Unemotional

38. Chemistry

Calculate the theoretical pH at the starting point and at each equivalence point for phosphoric acid, acetic acid, and sulfuric acid. Please show the equilibrium equation, the Ka, and the pH calculation.

39. Social Studies

I am an investor in the Virginia Company. What is a reason of why people should leave England and move to Jamestown. What are the two advantages of living in Virginia? Thank you.

40. Chemistry 143

Write three thermochemical equation needed to calculate delta H for the following reaction: 2Mg(s) + O2(g) = 2MgO Include delta h values in kJ for each reaction. Please help!! I don't even know were to start!!

41. algebra

Trains a and b are traveling in the same direction on parallel tracks. Train a is traveling at 40 mph and train b is traveling at 50mph. Train a passes a station at 12:15 a.m. If train b passes the same station at 12:27a.m. at what time will train b catch

42. math

a pickup truck has a main tank with a 17 3/4 gallon capacity and an auxiliary tank which holds 15 1/8 gallons. if the truck gets 14 6/10 mpg, how far can the truck trqavel before running out of gas?

43. Word Problem

Can someone help me figure out the equation? I am not good at figuring this out. Investing her bonus. Donna invested her \$33,000 bonus and received a total of \$970 in interest after 1 year. If part of the money returned 4% & the remainder 2.25%, how much

44. Linear algebra

Let L1 be the line passing through the points Q1=(−2, 1, 1) and Q2=(−4, 4, 0) and let L2 be the line passing through the point P1=(−6, −6, 0) with direction vector →d=[9, 6, 3]T. Determine whether L1 and L2 intersect. If so, find the

45. algebra

Plus or minus of 0.05: As measured in standard deviations, how much is a year of learning in school worth on a test? Please answer with a decimal.

46. science

why it is important to take care of the eyes and go for a regular checkup?

47. math

Sven is thinking if two numbers. The sum is 12 . The difference is 4. What are the two numbers

48. chemistry

When compared to compound B, compound A has lower melting and boiling points and vaporizes more readily. Is compound A an ionic compound or a molecular compound? A. Ionic B. Molecular I say B

49. math

What is the percent by mass of oxygen in H2O? A. 11.1% O B. 50.0% O C. 88.9% O D. 95.0% O I think C

50. math

what is the mass of 1.00 L of ethanol? Ethanol has a density of 0.798 g/ml. (hint: one liter is 10^3 mL.) A. 0.789 g B. 789 g C. 789 L I think C

51. math

what is the mass of 12.0 ml of a substance with the density of 0.922 g/cm3? A. 1.11g B. 0.11g C. 11.1 g I think C.

52. math

what is the specific gravity of a substance that has a density of 1.59 g/cm3? A. 1.59 g/mL B. 1.59 g C. 1.59 D. 1.59 mL I think B.

53. english

The following sentence shows what element of poetry? Her fiery eyes swept away his heart. A. Imagery B. Figure of speech C. Personification D. Simile

54. spanish

what dose tengo sed puedo ira

55. science

Does flowers store food?

56. cell biology

How can we differentiate MMPs from different proteolytic enzymes

57. statisics

A major hurricane with wind speeds of 111 per hour or greater. During the last century the mean number of major hurricanes to strike a certain country mainland per year was about 0.45. Find the probability that in a given year exactly one major hurricane

If u carry out a SWOT analysis you should know the " O" stands for a) outliers. B) opportunities c) outlines d) oddities

59. British literature

How do Falstaff's adventures mirror the main plot in Shakespeare's Henery the 4th

60. CURRENT PROCD TERMN CODING

wHAT IS THE CODING SYSTEM PHYSICIANS USE TO FILE THEIR CLAIMS

61. chemistry

Which of the following consists of positive and negative ions bound together and held in place in a crystalline solid? A. Covalent bonds B. Ionic compounds C. Molecular compounds D. Molecules I say B

62. chemistry

Which ion is absorbed by a base in water? A. H3O+ B. OH- C. Neutron D. Transition metal B

63. chemistry

What is usually indicated by an -ite or -ate ending in a chemical formula? A. The compound carries a net ionic charge of zero. B. The compound contains a polyatomic ion. C. The compound is an acid. D. The compound is molecular. I think A

64. math

127.1 g Cu combines completely with 32.1 g S to form a compound. What is the percent composition of this compound? A. 20% Cu; 80% S B. 50% Cu; 50% S C. 80% Cu; 20% S D. 127% Cu; 32% S I say A

65. math

If there is a 75.0 g quantity of carbon present in each 100 g of a carbon and hydrogen compound, what is the percent composition of hydrogen in this compound? A. 25 g B. 25% C. 75 g D. 75% I say B

66. math

In order for the percent composition of a compound to be calculated, the molar mass of the compound and the chemical formula must be determined. True False I say true

67. math

How is percent composition calculated? A. Dividing the mass of each element in the compound by the total mass of the compound and then dividing by 100% B. Dividing the mass of each element in the compound by the total mass of the compound and then

68. math

If there is a 75.0 g quantity of carbon present in each 100 g of a carbon and hydrogen compound, what is the percent composition of hydrogen in this compound? A. 25 g B. 25% C. 75 g D. 75% I say B

69. math

Convert 1,144 oF to oC A. 617.8 B. 617.8 oC C. −617.8 oC D. −617.8 I say B

70. math

To add numbers using scientific notation, multiply the coefficients and then add the exponents. true or false true

71. math

Solve the following and express the answer in scientific notation: (5.4 x 10^4) - (2.5 x 10^6) A. -2.45 x 10^6 B. 2.45 x 10^6 C. -2.45 x 10^8 D. -2.44 x 10^2 I say D

72. math

Solve the following and express the answer in scientific notation: 10^3 x 10^4 x 10^-2 A. 10^5 B. 10^6 C. 10^7 d. 10^8 I say A

73. math

Solve the following and express the answer in scientific notation: (5.3 x 10^4) + (2.2 x 10^3) A. 5.5 x 10^4 B. 7.5 x 10^3 C. 7.5 x 10^7 D. 11.7 x 10^7 I say A

74. math

The melting point of helium is -272.2 oC. Express this temperature in kelvins. A. -272 K B. -8.0 K C. 0.8 K D. 545 K I say D.

75. math

if the density of .88 grams of mercury is 13.6 g/ml, what is the volume? A. 0.065 mg B. 0.065 C. 0.065 ml D. 0.065 L I think its C.

76. math

If melted butter were poured into a glass of milk and allowed to rest, two distinct layers would be visible. How would these layers appear? A. The melted butter would lie above the layer of milk because butter is less dense than milk. B. The melted butter

77. Physics

Find the angle that the vector R = A + B makes with the positive x axis, use counter- clockwise as the positive angular direction, between the limits of −180 degrees and +180 degrees. Answer in units of degrees

78. math

6.8 in fraction notation

what are energy bar graphs?

80. math

My friend found two old watches. He wound them, set them, and started both of them at the same time. He placed the two old watches on one wrist and his new watch on the other wrist. Forty-five minutes later one of the old watches had gained 1 minuate and

81. math

Solve the following and express the answer in scientific notation: 10^3 x 10^4. A. 10-^1 B. 10^1 c. 10^6 D. 10^7 I say D

82. Algebra

Graph the absolute value inequalities. I just can not get this. Please help! x + 2y ¡Ý 6

1. Linear algebra

Bob and Doug play a lot of Ping-Pong, but Doug is a much better player, and wins 90% of their games. To make up for this, if Doug wins a game he will spot Bob five points in their next game. If Doug wins again he will spot Bob ten points the next game, and

posted on April 15, 2017
2. Algebra

Thank you so much

posted on March 19, 2017
3. chemistry

posted on May 22, 2016

6+10*2

posted on February 24, 2016
5. math

6+10*2 the expression equal 32

posted on February 24, 2016
6. math

3+5*2-210=6

posted on February 24, 2016
7. Math

32.04 x300

posted on December 10, 2015
8. Finance

This is the answer to #5-Capital Co WACC 14.24%

posted on August 27, 2013
9. Finance

THis is the answer to #3 Bell Vineyards 0 \$2,000 1 \$2,460 2 \$2,780 3 \$2,986 4 \$3,101 5 \$3,144 Year 6 to purchase

posted on August 27, 2013

estimate the sales tax and final cost of a book that costs \$12.99 with a sales tax of 6%

posted on January 23, 2013
11. math

think its 13.6 g

posted on November 7, 2012
12. Literature (Vocabulary)

charlatan naïve hoax amicable levity fickle mundane

posted on February 24, 2012
13. Social Studies

Okay, thank you

posted on September 15, 2011
14. College Chemistry

If i combust 1.0kg of octane according to the following unbalanced reaction , how many moles of carbon dioxide should i theoretically produce? 2 C8H18+ 25 O2 -> 16 CO2+ 18 H20

posted on April 7, 2011
15. Writing

31 Myself 32 who 33 they/their 34 they /their

posted on April 9, 2010
16. Writing

31 Myself

posted on April 9, 2010
17. history

i need help on history project is anyone alive in here

posted on February 22, 2009
18. history

ok hi

posted on February 22, 2009