Saturday

April 19, 2014

April 19, 2014

Total # Posts: 224

**Biology**

Briefly describe how the process of dehydration synthesis creates polymers.

**Chemistry**

nv/Ns=A*e(-Hv/(KT)) K=1.381E-23 Hv= 104000/6.023e+23 A=1 vacancy density=(nv/Ns)*Cu density*(6.023e+23/Cu atomic weight)

**Chemistry**

No, I didn't find that answer.

**Chemistry**

Ev= elastic strain energy per unit vol=? Ev=(1/2)*Ey*E2(square) Ey= 8.0*10e+10 N/m2 E= 9.0e-3 so square -> E2= 8.1e-5

**Chemistry**

The Young's modulus for a material is 8.0 x 1010 N/m2. The material is stretched to a strain of 9.0 x 10-3. How much elastic energy will be expended? (Express your answer in J/m3). Answer: 3240000

**Math**

There are some caps in a box. 1/6 are red, 1/3 are blue, and 3/7 of the remainder are green. If there are 27 green caps, how many caps are there all together?

**Biology/Chem**

Soy sauce is prepared by fermenting a salted mixture of soybeans and wheat with several microorganisms including yeast over a period of 8-10 months. After the solids are removed, the resulting sauce is rich in lactic acid and ethanol. How aere these 2 compounds produced? In or...

**Chemistry**

A 50mL solution of Histidine-HCl (Histidine: pKa1=1.8, pKa2=9.2, pKa3=6.0)is titrated with 0.500M NaOH. What is the expected pH of the histidine solution at the points in the titration when 14.0mL, 26mL, and 38mL of the NaOH titrant is added?

**Chemistry**

The extracellular concentrations of Na+ and K+ are 135mM and 6mM, respectively. The intracellular concentrations of Na+ and K+ are 10mM and 105mM, respectively. The membrane potential is 75mV. For Na+/K+ ATPase, 3Na+ are exported and 2K+ are imported. Calculate the total free ...

**Algebra**

If Don Gecewicz invests $5000 at 9% interest compounded quarterly, find the amount after 4 years.

**Math**

A teacher is choosing 4 students from a class of 30 to represent the class at a science fair. In how many ways can the teacher choose the students?

**algebra**

Christine lives in Bangor, Maine , and her friend Denise Brown lives in Sioux City, Iowa. They both drive to Dade City, Florida, for the winter. The trip is 1600 miles for Christine and 1500 miles for Denise. If Christine drives 5 miles per hour faster than Denise, and if they...

**Calculus**

Evaluate the following limits (x^2 + 2x - 8)/x-2 Lim x->2

**math**

how to do pre algebra pizzazz page e 28

**Math**

Raymond has exactly 360 square inches of cardboard to make a box.he wants two of the dimensions to be 6 inches and the other one to be a whole number of inches.how many different size boxes can he make?

**Math**

How many 6 inch pieces can you cut from a spool of ribbon that is 10 yards long?

**algebra**

not B, I mean A. -33

**algebra**

Find the 11th term of the arithmetic sequence 7, 4.4, 1.8, -0.8, … A. -33 B. -19 C. 33 D. 19 B

**algebra**

Find S10 for (-1) + (-7) + (-13) + (-19) +... A. 250 B. -280 C. (-23) D. 132 C.

**algebra**

Find S25 for (-7) + (-2) + 3 + 8 +... A. 1,320 B. 1,325 C. 825 D. 820 I think A

**algebra**

Find S25 for 1/2 + 1 + 3/2 + 2 +... A. 160 B. 162 C. 160.5 D. 162.5 I think D

**algebra **

Find S10 for 2 + 5 + 8 +... A. 155 B. 152 C. 255 D. 135 I say A.

**Algebra**

Jennifer has a recipe that calls for horseradish sauce that is 45% pure horseradish. At the grocery store she finds one horseradish sauce that is 30% pure horseradish and another that is 80% pure horseradish. How many teaspoons of each of these horseradish sauces should Jennif...

**Math**

Althea invested $10,000 for one year, part at 7% and part at 6 1/4%. If she earned a total interest of $656.50, how much was invested at each rate?

**government**

During its early history, the British Parliament _____.

**government**

During its early history, the British Parliament _____.

**algebra**

Find the maximum or minimum of the following quadratic function: y = x2 - x - 56. A. -56 B. 56 C. -225/4 D. 225/4 d

**algebra**

Which of the following relations is a function? A. {(5, 2), (3, 2), (4, 2), (5, 1)} B. {(1, 2), (1, 3), (2, 1), (3, 4)} C. {(1, 3), (2, 6), (3, 8), (1, 7)} D. {(1, 4), (8, 9), (10, 11), (12, 12)} I say c

**algebra**

f of x = the square root of 2x minus 5 Find f(7) A. 2 B. 3 C. -5 D. 7 A

**algebra**

f of x = the square root of 2x minus 5 Find f (27) A. 2 B. 3 C. -5 D. 7 D not sure on this stuff, could you explain the steps?

**algebra**

Determine if the inverse of function {(-3, -6), (-1, 2), (1, 2), (3, 6)} is also a function. A. function B. not a function B

**algebra**

f of x = the square root of 2x minus 5 Find f(4.5) A. 2 B. 3 C. -5 D. 7 B

**algebra**

could you explain the steps?

**algebra**

What is the range of the inverse of relation {(1, 7), (2, -4), (5, 6), (2, 8)}? A. {1, 2, 5} B. {-4, 6, 7, 8} C. {1, 5} D. {-4, 7, 8} B

**algebra**

Simplify the rational expression: x−5 /x 2 −x−20 A. x−4 B. x+4 C. x 2 −15 D 1 /x+4 D

**algebra**

Find f o g if f(x) = 2x - 1 and g(x) = x + 2. A. 2x - 3 B. 2x + 1 C. 2x - 1 D. 2x + 3 B

**algebra**

Find f o g if f(x) = x + 7 and g(x) = 3x – 2. A. 3x + 5 B. 3x - 5 C. 3x + 19 D. -3x - 19 D

**algebra**

Find g of f if f(x) = 2x - 1 and g(x) = x + 2. A. 2x - 3 B. 2x + 1 C. 2x - 1 D. 2x + 3 D

**algebra**

Find g o f if f(x) = x + 7 and g(x) = 3x – 2. A. 3x + 5 B. 3x - 5 C. 3x + 19 D. -3x - 19 C

**algebra**

Find f(x)·g(x) if f(x) = 3x and g(x) = x + 1. A. 3x2 + 3x B. 3x + 1 C. 4x + 1 D. 3x2 + 1 D

**algebra**

Find the slope between points (4, 6) and (-2, 6). A. 0 B. Undefined slope C. one fourth D. -4 D

**algebra**

Find f(x)·g(x) if f(x) = 3x and g(x) = x + 1. A. 3x2 + 3x B. 3x + 1 C. 4x + 1 D. 3x2 + 1 A

**algebra**

I got B and C mixed up, I meant to say C B is suppose to be x^2

**algebra**

If f(x) = 2x and g(x) = ½ , calculate f(x) • g(x) A. x B. x2 C. 2x D. 2x2 I say B

**Physics**

A mass m1 = 4.1 kg rests on a frictionless table and connected by a massless string to another mass m2 = 5.9 kg. A force of magnitude F = 32.0 N pulls m1 to the left a distance d = 0.83 m. 1) How much work is done by the force F on the two block system? 2) How much work is don...

**physics**

Calculate the speed of a 10,000 kg airliner with a kinetic energy of 3.1 x 10^9 J.

**physics**

Calculate the speed of a 10,000 kg airliner with a kinetic energy of 3.1 x 10^9 J.

**Math**

37% of college students say they use credit cards because of the rewards program. You randomly select 10 college kids and ask each to name the reason he or she uses credit cards. Find the probability that the number of college students who say they use credit cards because of ...

**chemistry**

whoops D

**chemistry**

solve the following and express your answer in scientific notation: (5.3 x 10^4) + (1.3 x 10^3) A. 5.4 X 10^4 B. 5.4 X 10^8 C. 6.6 X 10^7 D. 6.9 X 10^7 I say c

**chemistry**

got it now B

**chemistry**

one isotope of chromium (atomic number 24) has an atomic mass of 53 amu. how many neutrons are in this particular isotope of chromium? A. 24 B. 29 C. 53 D. 77 I say A

**chemistry**

amphetamine (c9h13n) is a powerful stimulant. what is the percent composition of all of the elements in this compound? A. 9%C;13%H;1%N B. 30%C;10%H;60%N C. 60%C;35$H;5%N D. 80%C;9.6%H;10.4%N I think b

**chemistry**

C. 81.8%

**chemistry**

what is the percent by mass of carbon in c3h8? A. 18.20% B. 20.0% C. 81.8% D. 85.0% I say A

**chemistry**

how many moles are in 243.6 g caco3? A.7.41 mol caco3 B 2.43 mol caco3 C.102.46 mol caco3 D.88.1 mol cao3 I say A

**chemistry**

a compound is found to be 94.1% o and 5.90% h. its molecular mass is 34.0. what is its molecular formula A. H3O2 B. OH C. H2O D. H2O2 I think D

**Physics**

A roller coaster is initially at a height of 40 m above the ground and has an initial velocity of 15 m/s. Using conservation of energy, find the velocity of the roller coaster at a height of 5 m above the ground.

**chemistry**

in the formula for calcium bromide (CaBr2), what does the subscripted two indicate? A. the bromide atom has a charge of 2- B. the bromide atom has a charge of 2+ C. there are two bromide atoms for every calcium atom. D. there are two calcium atoms for every bromide atom I say C.

**chemistry**

what is the formula for the arsenic ion. A. As3- B. As2- C. As, D. As3+ I say c.

**chemistry**

how many electrons does Fe3+ gain or lose when the ion forms? A. gains 1 electron B. loses 1 electron C. gain 3 electrons D. loses 3 electrons I think D.

**chemistry**

the fluoride anion always carries a charge of 1- true or false I say true

**chemistry**

Lithium-6 has an atomic number of 3. How many electrons are in this isotope? A. 0 electrons B. 3 electrons C. 6 electrons D. 9 electrons I think C. 6

**chemistry**

Lithium-6 has an atomic number of 3. How many protons are in this isotope? A. 0 protons B. 3 protons C. 6 protons D. 9 protons I think 3

**chemistry**

boron-10 has an atomic number of 5. how many electrons are in this isotope? 0 electrons, 2 electrons, 5 electrons, 10 electrons. I think 10

**chemistry**

boron-10 has an atomic number of 5. how many neutrons are in this isotope? 0 neutrons, 2 neutrons, 5 neutrons, 10 neutrons. I say 5

**chemistry**

the idea of the atom was first proposed by john dalton. true or false false

**chemistry**

Actinides and Lanthanides are elements in group 3A. true or false I say false

**chemistry**

Lithium-6 has an atomic number of 3. how many neutrons are in this isotope? A. 0 neutrons, B. 3 neutrons, C. 6 neutrons, D. 9 neutrons I say B

**chemistry**

guessed

**chemistry**

meant A

**chemistry**

What is the molar mass of hydrogen? A. 1.01 g/mol B. 11.01 g/mol C. 101.1 g/mol D. .0111 g/mol D

**chemistry**

How many atoms are in 3.14 mol of methane (CH4)? A. 7.56 x 1023 atoms B. 7.56 x 102 atoms C. 7.56 x 104 atoms D. 7.56 x 1024 atoms D

**chemistry**

What is a problem-solving technique that uses equivalent measurements in ratio form to solve problems? A. Avogadro's number B. Conversion C. Dimensional analysis D. The mole concept A

**chemistry**

In order to determine the number of atoms in a compound, you must know the number of atoms in a representative particle of the compound. True False i think false

**chemistry**

How many moles are in 4.81 x 1024 atoms Na? A. 0.799 mol Na B. 7.99 mol Na C. 481 mol Na D. 7.99 x 10-1 mol Na B

**chemistry**

How many atoms are in 1.14 mol of propane (C3H8)? A. 7.55 x 1023 atoms B. 7.77 x 1024 atoms C. 7.55 x 1024 atoms D. 7.55 x 1030 atoms C

**chemistry**

How many moles of magnesium is 1.25 x 1023 atoms of magnesium? A. 0.208 × 101 mol Mg B. 2.08 × 101 mol Mg C. 2.08 × 10 -1 mol Mg D. 20.8 mol Mg I think it would be D

**chemistry**

What is the gram molecular mass of C2H6? A. 8.0 g B. 30.0 g C. 40.0 g D. 50.0 g think B

**chemistry**

What is the gram fomula mass of calcium carbonate (CaSO4)? A. 6 g B. 136.2 g C. 230.0 g D. 235.4 g think B

**chemistry**

thank you

**chemistry**

The chemical explosive nitroglycerine has the formula C3H5(NO3)3. How many oxygen atoms are in the formula unit for this compound? A. 3 B. 6 C. 9 D. 12 C. 9

**chemistry**

The water molecule (H2O) is composed of 2 atoms of hydrogen and one atom of oxygen. What is the mass of one mole of water? A. 3 g B. 18 g C. 6 g D. 6.02 x 1023 g B. 18 g

**math**

On a cold winter day, the temperature is -10.0º C. What is the reading on the Fahrenheit scale? A. 10.0 oF B. 12.0 oF C. 13.0 oF D. 14.0 oF I say A

**math**

The temperature of the water around a nuclear reactor core is about 300 oC. what is this temperature in degrees Fahrenheit? A. 27 oF B. 332 oF C. 572 of D. 573 oF I say D

**math**

Solve the following and express the answer in scientific notation: (5.4 x 10^4) x (4.5 x 10^8) A. 2.4 x 10^10 B. 24 x 10^11 C. 24 x 10^12 D. 2.4 x 10^3 I say D

**Science**

The "resistant" threshold for gemifloxacin is >1 mg/L while the "resistant" threshold for sulfamethoxazole is >512 mg/L. Explain why there might be this great disparity of values in resistance thresholds (512-fold) for each antibiotic pharmacologicall...

**physics**

thanks, but how come m is not in kg?

**physics**

Just an explanation without numbers would be awesome, i just want to understand the correct steps to take. Thanks!

**physics**

Ice fishing equipment weighing 3,000 N is pulled at a constant speed V = 0.5 m/s across a frozen lake by means of a horizontal rope. If the coefficient of kinetic friction is 0.05, what is the work done (in J) by the fisherman in pulling the equipment a distance of 500 m?

**Chemistry**

got it thanks!

**Chemistry**

Another hour gone by working on this and i still can't figure it out. Im totally lost!

**Chemistry**

A mixture of ethane and ethene occupied 35.5 L at 1.000 bar and 405 K. This mixture reacted completely with 110.3 g of O2 to produce CO2 and H2O. What was the composition of the original mixture? Assume ideal gas behavior Im pretty sure i use dalton's law of partial pressu...

**Physics**

A tennis ball is thrown horizontally from an elevation of 20.60 m above the ground with a speed of 19.0 m/s. (a) Where is the ball after 2.00 s for the horizontal and vertical position? (b) If the ball is still in the air, how long before it hits the ground? If the ball is sti...

**Math**

Fiind the area bounded by the parabola y^2 = 8x, the x axis and the line x=2

**Physics**

a quarter sits at the bottom of a wishing well where the gauge pressure reads 294 kPa. If the quarter has a diameter of 24mm, what is the total force acting on the top surface of the quarter? Note: Atmospheric pressure = 101.3

**Calculas**

square root of 2x

**Calculas**

Find the length of the curve y=ã(2x), from x=1 to x=4.

**chemistry**

Nitrogen-13 has a half-life of 10 minutes. Given a starting mass of 2.00 g of nitrogen-13, how many grams will remain at the end of 30 minutes?

**chemistry**

What is the molarity of the solution produced when 14.1 grams of ammonia is dissolved in sufficient water to prepare .100 liters of solution?