Saturday

November 28, 2015
Total # Posts: 88,381

**Science**

Which of the following gases was most likely present in Earth's earliest atmosphere? A. nitrogen B. hydrogen* C. argon D. oxygen Which of the following statements accurately describes the development of the geologic time scale? A. Scientists developed the geologic time ...
*November 16, 2015*

**Algebra**

I got it already but thanks anyways Steve :)
*November 16, 2015*

**Algebra**

In a table, how do you tell if y varies directly with x and write an equation if it does?
*November 16, 2015*

**SS**

What is an example of a person in history who broke soceital rules?
*November 16, 2015*

**SS**

What is an example of a criminal or bad person in Babylon?
*November 16, 2015*

**Science CHECK ANSWERS PLZ**

Which of the following gases was most likely present in Earth's earliest atmosphere? A. nitrogen B. hydrogen* C. argon D. oxygen Which of the following statements accurately describes the development of the geologic time scale? A. Scientists developed the geologic time ...
*November 16, 2015*

**math**

3*13 - 2 - 10 + 12/2
*November 16, 2015*

**Algebra**

assuming the same tax bracket, etc. (3030/5200)*(57/52)
*November 16, 2015*

**Physics**

a boy runs 10m/sec at 10m/sec and he walks for 30 sec at 10m/sec what is the average of speed of the boy ? A\ 5M/S B/ 20M/S C/15M/S D/10M/S E/ None
*November 16, 2015*

**10th grade**

Ravi resigned----------illness
*November 16, 2015*

**math**

Could someone please check my answer to this question: Evaluate the expression [(x^n)(y) + (y^n)] ^-2n for x=-2, y=3 and n=-1 =[(x^-1)(y)+(y^-1)]^-2(-1) =[(x^-1)(y)+(y^-1)]^2 =[(x^-2)(y^2)+(y^-2) =y^2/x^2(y^2) =3^2/(-2)^2(3^2) =9/4(9) =9/36 =1/4
*November 15, 2015*

**Algebra 1**

Evaluate: 1 5 9 × 1 8 Give your answer in its simplest form.
*November 15, 2015*

**Physics HELP**

How would I solve this problem? A plane travels 4300 m at an angle of 49 degrees to the ground, then changes direction and travels 6500 m at an angle of 21 degrees to the ground. What is the magnitude and direction of the planes tot displacement?
*November 15, 2015*

**SOC 320**

Which of the following is among the Courts’ means of influencing implementation? (Points : 1) Judicial review of administrative rules and rule making Direct oversight of executive branch agencies Routine judicial review of appropriations Intervening in policy cases they ...
*November 15, 2015*

**Chemistry**

I'm confused. Why do you use log and why do you do 1/H2SO4? I found this equation in our textbook: Ecell=Eocell-(RT/nFl)nQ When I use that equation I get 2.00, when I use the equation you've given I get 2.05. I know it's a small difference but why? Thank you
*November 15, 2015*

**Chemistry **

Given: PbSO4 + 2e− Pb + SO42− E° = -0.356 V PbO2 + 4H+ + SO42− + 2e− PbSO4 + 2H2O E° = 1.685 V Determine the cell voltage of the lead storage battery when the concentration of sulfuric acid is 4.00 M. Where do I start, thank you
*November 15, 2015*

**physics**

When a wood shelf of mass 7.2 kg is fastened inside a slot in a vertical support as shown in (Figure 1) , the support exerts a torque on the shelf. Assume that the slot exerts two vertical forces on the shelf, at points A and B. Detrmine the force exerted on the shelf by the ...
*November 15, 2015*

**physics**

When a wood shelf of mass 7.2 kg is fastened inside a slot in a vertical support as shown in (Figure 1) , the support exerts a torque on the shelf. Assume that the slot exerts two vertical forces on the shelf, at points A and B.
*November 15, 2015*

**Maths **

Statistics The marks scored by a sample of 56 students are summarised by: N=56 Sum of x =3026 sum of(x-the mean)^2 =15378 A) calculate the mean and the standard deviation Mean I got - 54.04 (2.dp) Standard deviation I got - 16.72 (2.dp) Is this correct? B) the formula y=1.2x-...
*November 15, 2015*

**Physics HELP**

A bug on a picnic table travels 10 cm east, then 18 cm northward, and finally 20 cm westward. What is the bugs displacement relative to its original position?
*November 15, 2015*

**PLEASE I NEED HELP MS SUE**

in the heart blood flows from the right atrium to the right ventricle where it is pumped to the ______ openstudy
*November 15, 2015*

**math**

An aeroplane flies due north from Ikeja Airport for 500km. It then flies on a bearing of 060 degrees for a further distance of 300km before overflying a road junction.Calculate a. The distance of the aeroplne from Ikeja Airport when it was directly above the road junction. B....
*November 15, 2015*

**Math**

What is the numerical expression for 8[(20-4)-6]
*November 15, 2015*

**maths plz help**

Painters A and B take 3 hours to paint a room Painters B and C take 5 hours to paint the same room Painters A and C take 7 hours to paint the same room How long would it take all three to paint the same room?
*November 15, 2015*

**Physics**

If the magnetic field in a traveling EM wave has a peak value of 17.9nT, what is the peak value of the electric field strength?
*November 15, 2015*

**math**

is (3,7) correct
*November 15, 2015*

**math**

solve the system by substitution -4x-5y=-47 x=2y-11
*November 15, 2015*

**Maths**

Statistics The marks scored by a sample of 56 students are summarised by: N=56 Sum of x =3026 sum of(x-the mean)^2 =15378 A) calculate the mean and the standard deviation Mean I got - 54.04 (2.dp) Standard deviation I got - 16.72 (2.dp) Is this correct? B) the formula y=1.2x-...
*November 15, 2015*

**physics**

A disk shaped yoyo (m=220 grams) has a 70 cm long string. The radius of the central winding peg is 2.5 mm, the outer radius of the yoyo is 5.6 cm. A) How much Torque is applied to this yoyo by the string? B) How long until the yoyo hits the bottom of the throw? C) What is the ...
*November 15, 2015*

**Chemistry **

10000 tonnes of iron reacted in a blast furnace Fe2O3 calculate the typical mass of iron produced each day
*November 15, 2015*

**PHYSICS**

A BALL IS PROJECTED VERTICALLY UPWARD FROM THE TOP OF A TOWER 60MITRE HIGH WITH A VELOCITY OF 30MITRE PER SECONDS.WHAT IS THE MAXIMUM HEIGHT ABOVE THE GROUND LEVEL?HOW LONG DOES IT TAKE TO REACH THE GROUND?
*November 15, 2015*

**Physics**

rotating space station has radius 1380 m, measured from the center of rotation to the outer deck where the crew lives. What should the period of rotation be if the crew is to feel that they weigh one-half their Earth weight?
*November 15, 2015*

**Biology**

simulate a 24 hour day 12 hours of light 12 hours of dark how many snails and plants do you ened to keep a stable environment
*November 14, 2015*

**Biology**

Animals breathe in ___ and breathe out __ In sunlight plants take in ___ and realease __
*November 14, 2015*

**Biology**

What gas do plants give off in the light
*November 14, 2015*

**Biology**

Why don't we run out of the important gases that we need to stay alive?
*November 14, 2015*

**chemistry**

Consider an atom traveling at 1% of the speed of light. The de Broglie wavelength is found to be 9.50 × 10–3 pm. Which element is this?
*November 14, 2015*

**Centripetal acceleration**

Is this right? Tarzan plans to cross a gorge by swinging in an arc from a hanging vine. If his arms are capable of exerting 1350 N on the vine, what is his acceleration at the point where the vine makes an angle of 45 degrees from the vertical assuming maximum speed at this ...
*November 14, 2015*

**Government**

To what extent do cabinet heads control the bureaucracy?
*November 14, 2015*

**Physics**

Tarzan plans to cross a gorge by swinging in an arc from a hanging vine. If his arms are capable of exerting 1350 N on the vine, what is his acceleration at the point where the vine makes an angle of 45 degrees from the vertical assuming maximum speed at this point. His mass ...
*November 14, 2015*

**algebra**

eq 1: y miles/(6 mph + x mph)=3 hr eq 2: y miles/(6 mph - x mph)=5 r multiply both sides by the numerator on the left eq 1: y =18 + 3x eq 2: y =30 - 5x subtract equation 2 from equation 1 0=-12 + 8x 12=8x 12/8+x
*November 14, 2015*

**algebra**

Chen's motorgoat took 3 hr to make a treip downstream with a 6-mph current. The return trip against the same current took 5 hr. Find the speed of the boat in still water.
*November 14, 2015*

**PE**

How does breathing change during exercise? Rate and depth decrease Rate and depth increase Rate increases and depth decreases Rate decreases and depth increases I think Rate increases and depth decreases is correct, can someone confirm or object? Danke.
*November 14, 2015*

**Chemistry **

Given the following half-reactions and their standard reduction potentials, Ni2+ + 2e− Ni E° = -0.25 V 2H+ + 2e− H2 E° = 0.00 V Ag+ + e− Ag E° = 0.80 V a spontaneous reaction will occur between: a. Ni2+ and H2 b. H+ and Ag c. Ag+ and Ni d. Ni2+ ...
*November 14, 2015*

**Riddle**

Reflection
*November 14, 2015*

**Riddle **

to all things and men I appertain and yet by some am shunned and distend. Fonder me and ogle me till your Insane ,but no blow can harm me cause me pain. Children delight in me ,elders take fright, fair maids rejoice and spin. Cry and I weep,yawn and I sleep,smile and I shall ...
*November 14, 2015*

**Spanish **

Would you use indicative or subjective in this sentence? Explain why? María prefiere que no _________________ (haber) mucha gente en la playa. (I think that you would use subjective because "haber" can count as a subjective change and it has a verb of influence)
*November 14, 2015*

**Health**

u stupid
*November 14, 2015*

**physics**

The AM frequencies of a radio dial range from 550 kHz, and the FM frequencies range of 88.0 MHz to MHz. all of these radio waves travel at a speed of 3.0x10^8 m/s, what are the wavelenght ranges of a.) the aM brand b.) FM brand
*November 14, 2015*

**physics**

A circular disk of 10cm radius is charged uniformly with a total charge of Q. Find the electric field intensity at a point 20cm away from the disk along its axis
*November 14, 2015*

**literature**

Whose account of climbing everest was more appealing to you
*November 13, 2015*

**Math**

let the 10 digit number be x let the one digit number be y x + y = 14 , y= 14 - x original number 10x + y reversed number 10y + x equation 10y +x = 10x +y +36 subsitute for y 10(14-x) + x = 10x +14 - x + 36 140 - 10x + x = 10x +14 - x + 36 x = 5 y = 14 - x y = 14 - 5 = 9 ...
*November 13, 2015*

**Chemistry (Check)**

Here is my work, I might have gotten the answers the wrong way. 6.3 mg / 1000 = .0063g 385 mL / 1000 = .385 L 25 degrees C + 273 = 298 K 11 Torr / 760 = .0145 atm .0145 atm x .385L = n (.08206 Latm/molK) 298K n = 2.28x10^-4 moles A. MM = .0063g / 2.28x10^-4mole = 27.597 g/mol ...
*November 13, 2015*

**Chemistry (Check)**

6.3 mg of a boron hydride is contained in a flask of 385 mL at 25. degrees C and a pressure of 11 Torr. A. determine the molar mass of the hydride. B. which of the following hydrides is contained in the flask, BH3, B2H6, or B4H10 A. MM = 27.597 g/mol B. B2H6
*November 13, 2015*

**Chemistry**

Density = 2.82 g/L
*November 13, 2015*

**Chemistry**

Calculate the density (g/L) of 478 mL of krypton at 47 degrees C and 671 mmHg. I wasn't sure about this one but I got: density = 2820 g/L with sig figs
*November 13, 2015*

**Chemistry (Check)**

A sample of helium has a volume of 521 cc at a pressure of 75 cmHg and a temperature of 18 degrees C. When the temperature is increased to 23 degrees C, what is the volume of the helium? Vf = .530 L
*November 13, 2015*

**Children Development**

Thanks for the help.
*November 13, 2015*

**Children Development**

At Erickson Autonomy Shame and Doubt stage how do parents hinder or promote a child development?
*November 13, 2015*

**Chemistry (Check)**

It does. Thank you so much for all your help.
*November 13, 2015*

**Chemistry (Check)**

Mine doesn't round up. What did I do wrong? 15.0 L 27 degrees C + 273 = 300K 900. mmHg / 760 mmHg = 1.18 atm 1.18 atm x 15.0 L = n (.08206 Latm / mol K) 300K n = .719 moles NH3 x (17.03056g / 1 moleNH3) = 12.2449 g NH3
*November 13, 2015*

**Chemistry (Check)**

Calculate the mass of 15.0 L of NH3 at 27 degrees C and 900 mmHg. Mass of NH3 = 12.2 g
*November 13, 2015*

**Chemistry (Check)**

A container holds 500. mL of CO2 at 20. degrees C and 742 Torr. What will be the volume of the CO2 if the pressure is increased to 795 Torr? Vf = .465 L
*November 13, 2015*

**Chemistry**

Given 300.0 mL of a gas at 17.0 degrees C. What is its volume at 10.0 degrees C? Vf = .293 L
*November 13, 2015*

**Chemistry (Check)**

A 30.0 L sample of nitrogen inside a rigid, metal container at 20.0 degrees C is placed inside an oven whose temperature is 50.0 degrees D. The pressure inside the container at 20.0 degrees C was at 3.00 atm. What is the pressure of the nitrogen after its temperature is ...
*November 13, 2015*

**Chemistry (Check)**

Yes, Liters. sorry
*November 13, 2015*

**Chemistry (Check)**

Chlorine gas, Cl2, is widely used to purify municipal water supplies and treat swimming pool waters. If it occupies 23.5 cm^3 at STP, what volume will it occupy at -270. degrees C and a pressure of 1520 Torr? Vf = 1.29 x 10^-4
*November 13, 2015*

**Children Development**

Thanks I really appreciate your help Reed. I find the person your walrusy king to be really rude toward me.
*November 13, 2015*

**Children Development**

I am sorry The question is question what was happening in your life at this stage? is Your walrusy king a tutor?
*November 13, 2015*

**Children Development**

What?
*November 13, 2015*

**Children Development**

I cannot figure of what means by what life experiences i had at trust vs.mistrust stage of life?
*November 13, 2015*

**Chemistry (Check)**

A sample of gas has a volume of 12.0 L and a pressure of 20kPa. If the pressure of gas is increased to 50 psi, what is the new volume of the gas? Vf = 6.96 L
*November 13, 2015*

**Chemistry (Check)**

Ok thanks!
*November 13, 2015*

**Chemistry (Check)**

This is my work: 985mLN / 1000 = .985 L 0.0 degrees C + 273 = 273 K 1.00x10^-6 mmHg / 760 mmHg = 1.32 atm 1.32 atm x .985 L = n ( .08206 Latm / molK)x273K n = .0580 moles x 6.022x10^23 = 3.50 x 10^23 molecules. Ok thanks
*November 13, 2015*

**Chemistry (Check)**

3.50x10^23 molecules
*November 13, 2015*

**Chemistry (Check)**

How many molecules are there in 985 mL of nitrogen at 0.0 degrees C and 1.00x10^-6 mmHg? 3.50 molecules
*November 13, 2015*

**science plz help fast**

1 at least one is helped in both cases
*November 13, 2015*

**Chemistry (Check)**

If a gas in a closed container is pressurized from 12 atm to 25 atm and tis original temperature was 32 degrees C, what would the final temperature of the gas be? Tf = 635 K
*November 13, 2015*

**English**

I can read it but only if someone is reading it out loud with me it helps me focuse on the story better and I can do better on my schoolwork. Thanks to both of you :)
*November 13, 2015*

**English**

I need either an audio for the book "Nethergrave" by Gloria Skurzynski or an extremely detailed summary please.
*November 13, 2015*

**Math**

Can someone check my answers when a skydiver jumps from an airplane, the distance d in feet the diver falls in t seconds before opening the parachute is given by the formula d=16t2. the formula assumes that there is no air resistance. find the time it takes a skydiver to fall ...
*November 13, 2015*

**Calculus 1**

Reiny, Aren't we supposed to use distance formula for this though?
*November 13, 2015*

**social studies PLEASE HELP**

can someone actually help me??? (mrs sue)
*November 13, 2015*

**social studies PLEASE HELP**

which of the following is true of social classes? people in most societies cannot improve their status they are based mainly on age people can improve their status by getting a good education they are based mainly on gender im not sure what to even guess please help me
*November 13, 2015*

**Math**

Need to find out how many answers I got correct out of 40 questions. I ended with a zero at the end .5 points were given fr the correct answer while 3oints were deducted or the wrong answer
*November 13, 2015*

**Chemistry**

Show that the reaction caco3 ->cao+co2 is not a redox reaction
*November 13, 2015*

**Chemistry**

Carbon disulfide (CS2) is useful, but flammable, solvent. Calculate DH for the following reaction. CS2(l) + 3O2(g) --> CO2(g) + 2SO2(g)
*November 13, 2015*

**social**

Gold
*November 13, 2015*

**Math**

Can someone check my answers when a skydiver jumps from an airplane, the distance d in feet the diver falls in t seconds before opening the parachute is given by the formula d=16t2. the formula assumes that there is no air resistance. find the time it takes a skydiver to fall ...
*November 12, 2015*

**math**

A chalk line is placed around the perimeter of the football field. What is the length in feet?
*November 12, 2015*

**Chemistry**

Use the following data 2C(s) + 4H2(g) --> C3H8(g) DH= -103.85 kJ/molrxn C(s) + O2(g) --> CO2(g) DH= -393.51 kJ/molrxn H2(g) + 1/2O2(g) --> H2O(g) DH= -241.82 kJ/molrxn to calculate the heat of combustion of propane, C3H8 C3H8(g) + 5O2(g) --3CO2(g) + 4H20(g)
*November 12, 2015*

**Math**

6 and 7, yes
*November 12, 2015*

**Math**

Check my answer? As estimate for square root 47 is between _____________ 1: 4 and 5 2: 5 and 6 3: 6 and 7 4: 7 and 8 Is the answer 6 and 7?
*November 12, 2015*

**Chemistry**

Predict the Order of increasing bond length for (i) H2(g) (ii) I2(g) (iii) F2(g) I don't know how I should know
*November 12, 2015*

**Apology**

I don't know how this got copied three times. Sorry
*November 12, 2015*

**Chemistry**

Predict whether each of the following reactions would be exothermic or endothermic. a. CO(g) --> C(g) + O(g) b. 2H(g) + O(g) --> H20(g) c. Na+(g) + Cl-(g) --> NaCl(s) What is the sign of DH in each of these reactions? Please explain. I am very confused. Thanks
*November 12, 2015*

**Chemistry**

Predict whether each of the following reactions would be exothermic or endothermic. a. CO(g) --> C(g) + O(g) b. 2H(g) + O(g) --> H20(g) c. Na+(g) + Cl-(g) --> NaCl(s) What is the sign of DH in each of these reactions? Please explain. I am very confused. Thanks
*November 12, 2015*