Questions Asked on
February 14, 2015

Chemistry
1.2048g sample of impure Na2CO3 is dissolved and allowed to react with a solution of CaCl2 resulting CaCO3 after precipitation, filtaration and drying was found to weight 1.0362g. calculate the percentage purity of Na2CO3
asked by Ana 
chem uni
Insert correct coefficients it is a redox reaction Al2+MnO2=Al2O3+Mn
asked by CAMELA 
Calculus
a certain radioactive substance is decaying so that at time t, measured in years, the amount of the substance, in grams, is given by the function f(t)=3e^3t. What is the rate of decay of the substance after half a year: I first found the derivative of
asked by Sara 
Maths Dividing Farction
I need help to solve this:= 16 pies were shared among some women in a party. Each woman received 2/5 of a pie. How many women were there in the group?
asked by Sarah JJ 
Physics
How does the energy stored in a capacitor change if (a) the potential difference is doubled, and (b) the charge on each plate is doubled, as the capacitor remains connected to a battery?
asked by Anonymous 
PLEASE CHEM
balance the redox reaction NO2^ + Ag^+ = NO3^ + Ag
asked by LOLA 
Earth Science
15. _______ currents assist in the transfer of thermal energy from warmer climates to cooler climates. A. Platonic B. Plutonium C. Convection D. Tectonic C? Please explain
asked by Sarah 
physics
Because a concave lens cannot form a real image of a real object, it is difficult to measure its focal length precisely. One method uses a second, convex, lens to produce a virtual object for the concave lens. Under the proper conditions, the concave lens
asked by Ted 
Physics
A particle moving along the xaxis has its velocity described by the function v =2t squared m/s, where t is in s. Its initial position is x = 2.8m at t = 0 s. At 2.7s , what is the particle's position?
asked by Joan 
chemistry
Ethylene gas (C2H2) can be formed from the reaction of calcium carbide (CaC2) with water. What is the reaction rate if 14.2 grams of ethylene gas are produced over 4.00 seconds? The units are mol/s.
asked by danny 
Chemistry
6 mol sample of Cu2S is roasted in excess O2 to yield Cu metal and SO2. Calculate the mass of Cu metal produced
asked by Ana 
chemistry
Radioactive waste is difficult to dispose of due to the long time periods needed before the radiation effectively disappears. The US protocol is to store the waste for 10 halflives of the material after which the waste is no longer considered radioactive.
asked by danny 
chemistry
The activation energy of a reaction is typically determined by calculating the rate constant for the reaction at two temperatures and then manipulating the Arrhenius equation. If you determine the reaction rate constants for a particular reaction to be
asked by danny 
Anthropology
First describe how colonization and globalization have affected sociopolitical systems, and then discuss how political systems change. Give examples for each objective
asked by Casey 
philosophy
This is a prompt that I have to write a 600900 word response on. I have some ideas of what to talk about/address in regards to the prompt below such as answering if I believe in a supreme Being, then talking about how going to church has influenced my
asked by Tay Tay 
Physics
An airplane is travelling from Vancouver to Toronto following the jet stream. The plane cruised at an average speed of 1100 km/h for the 4000 km flight. How long did the flight take? If the plane left Vancouver at 3:00 am EST, what time did it arrive in
asked by GG 
Math
Hello, I can not solve problem from analytical geometry. If you can help me to find out what is wrong in my procedure and show me a better one I would be really gratefull. There are given 3 points A(2,2,3), B (6,3,0), C(3,1,1). On the x axaxis lies
asked by Viktória 
Math
Find all solutions for the complex numbers: a) z^4 = 9i 46 b) 8*sqrt3 / z^4 +8 =+i
asked by Complex number 
math
At Sunny;s Smoothies 2/5 of the smoothies are made with citrus fruit and the rest are made with berries.1/8 of the berry smoothies contain bananas.What fraction of all the smoothies are berry banana?
asked by shawn 
Math
The dissipation of heat through a composite material of width w centimetres can be modelled by the function f(w)=10/w0.77ln(w)–3.2 You are required to find the width of material that will prevent any heat dissipation. State what equation you will need
asked by Sam 
Maths Fraction
Need Help... 3/4 of a cake was shared by a group of children. Mrs.Lim gave each child 1/8 of the cake. How many children were there in the group?
asked by Sarah JJ 
Earth Science
12. The original location of an earthquake is also known as the A. horizon. B. epicenter. C. hotspot. D. magnitude. B?
asked by Sarah 
physics
A batted baseball leaves the bat at an angle of 33.0∘ above the horizontal and is caught by an outfielder 380ft from home plate at the same height from which it left the bat. 1. What was the initial speed of the ball? 2. How high does the ball rise above
asked by chibest 
Science
Science To determine the acceleration of an object moving in a straight line, you must calculate the change in its stored during each unit of A. Velocity. B. Time. C. Motion. ******* D. Deceleration Please help
asked by BUBBLES 
Algebra
Train A leaves station at 9am traveling east at 85 mph. Train B leaves station at 9:30 am traveling west. Both train are on the same track. At what time will they meet?
asked by Connor 
government
what court hears specific cases?
asked by kim 
Finance
You are planning to save for retirement over the next 15 years. To do this, you will invest $1,100 a month in a stock account and $500 a month in a bond account. The return on the stock account is expected to be 7%, and the bond account will pay 4%. When
asked by Kelsey 
Finance
You just acquired a mortgage in the amount of $249,000 at 6.75% interest, compounded monthly. Equal payments are to be made at the end of each month for 30 years. How much of the first loan payment is interest? (Assume each month is equal to 1/12 of a
asked by Kelsey 
Math
Train A leaves Tigerville at 9 am traveling east at 85 mph. Train B leaves Liontown at 9:20am travelling west at 60 mph on the exact same tracks. Tigerville and liontown are 154 miles apart. At what time will the trains meet?
asked by Connor 
Finance
Gene's Art Gallery is notoriously known as a slowpayer. The firm currently needs to borrow $27,500 and only one company will deal with them. The terms of the loan call for daily payments of $100. The first payment is due today. The interest rate is 21.9%,
asked by Kelsey 
Finance
You have an investment with 10 semiannual cash flows of $1000. The first payment is 6 months from today. If the EAR is 11% what is the present value of this investment?
asked by Kelsey 
Finance
If the APR is 7% with monthly compounding, compute the quarterly rate
asked by Kelsey 
French
Which sentence is correct? 1. J'ai anglais de matin. 2. J'ai anglais à matin.
asked by Anonymous 
Physics
A car and driver weighing 7740 N passes a sign stating “Bridge Out 27.7 m Ahead.” She slams on the brakes, and the car decelerates at a constant rate of 12.3 m/s^2. The acceleration of gravity is 9.8 m/s^2. What is the magnitude of the work done
asked by Jess 
Physics
Two objects of same material are travelling near you. Object A is a 1.5 kg mass traveling 13.5 m/s; object B is a 2 kg mass traveling 5 m/s. Which object would make you feel worse if you are hit by it? 1. B 2. A 3. Unable to determine 4. the same
asked by Kim 
math
A scale drawing of a city has a scale of 3 inches : 400 feet. What is the actual length of each foot in the drawing? Show the work.
asked by Alyssa 
Physics
If the rifle is stopped by the hunter’s shoulder in a distance of 3.16 cm, what is the magnitude of the average force exerted on the shoulder by the rifle? Answer in units of N. mass of bullet= 0.0137 kg velocity of bullet= 546 m/s to the right mass of
asked by Anonymous 
Chen UNi
This is another one for inserting coefficients HNO3+H2S=NO+H2O
asked by CAMELA 
chemistry
How do I find the initial rate of reaction for 4.)? 2NO(g)+Cl2(g) > 2NOCl(g) [NO] (mol/L) [Cl2] (mol/L) Initial Rate (mol/L * min) 1.) 0.20 1.) 0.10 1.) 0.63 2.) 0.20 2.) 0.30 2.) 1.92 3.) 0.80 3.) 0.10 3.) 2.58 4.) 0.50 4.) 0.50 4.) ???
asked by mar 
calc
find this value. tan(arctan(3)) how do ifind arctan 3
asked by kirsten 
Business Law
Can someone point me in the right direction so I can answer this ? Ezra enters into a written contract to purchase a house and lot from Joanne for $80,000. Before the closing, Ezra sees a better house for $70,000 and notifies Joanne that he has changed his
asked by Giovanna 
chemistry
A student measured the mass of a solid sample and recorded the mass on his data sheet as 20.587 grams. He recorded his initial volume as 7.9 mL and his final volume as 11.1 mL. Calculate the density of the sample.
asked by ako 
chemistry
Skim milk has a density of 1.028 g/mL. How many grams are needed to get 0.786L?
asked by ako 
Calculus
would the derivative of f(x)=(7^x)(x^7) be f'(x)=(7^x ln7) (7x^6)?
asked by Sara 
Algerba
A newspaper carrier has %5.75 in change. He has ten more quarters than dimes but two times as many nickles as quarters. how many coins of each type does he have?
asked by Tammy 
Earth Science
16. What type of instrument measures seismic waves? A. Mercalli scale B. Seismic scale C. Seismogram D. Seismometer D?
asked by Sarah 
physics
Galileo's first telescope used a convex objective lens with a focal length f = 1.65 m and a concave eyepiece. When this telescope is focused on an infinitely distant object, and produces an infinitely distant image, its angular magnification is +3.11. What
asked by Samantha 
English
I need help finding real life examples of these topics 1. The need to fight discrimination can be done by embracing who you are and refusing to conform to others expectations. 2. The importance of family is strong enough to overcome the temptation to give
asked by Amy 
chemistry
If the breakdown halflife of a pesticide applied to a farmer’s field is 3.50 days, then what is the rate constant for this reaction? Assume the degradation reaction follows first order kinetics. The units are 1/d.
asked by danny 
chemistry
In which of the following reactions is ΔE closest in value to ΔH? HNO3(aq) + Na2(CO3)(aq) = NaNO3(aq) + H2O(l) + CO2(g) KClO3(s) = KCl(s) + (3/2)O2(g) HCl(aq) + NaOH(aq) = H2O(l) + NaCl(aq) Na(s) + H2O(l) = NaOH(aq) + (1/2)H2(g)
asked by danny 
Pythagoras
An aeroplane flies 520 km north 45 degrees west then 387 km east . it is then noted that the plane is due north of its starting point. how far is the plane from its starting point? How do I work it out?
asked by Difficult 
math
For his next trick, a magician will draw a “royal flush” – 10, Jack, Queen, King and Ace of the same suit – in the exact order without replacement. If there are no magic tricks and just pure randomness, what is the probability that he'll succeed?
asked by probability 
math
find the dimensions of the subspaces of R^2 spanned by the vectors (1,3), (1,1)?
asked by maricel 
Calculus
Can someone please explain how to solve this type of question? Determine the maximum and minimum value of the function f(x)=3x3^x  1
asked by Sara 
Math
So far john has run 1/4 of the way to school and walked 3/8 of the way.What fraction of the distance to school does john have left?
asked by Anonymous 
Earth Science
18. Which of the following is a factor that determines the composition of magma? A. Texture B. Elasticity C. Color D. Viscosity D or B?
asked by Sarah 
math
A rectangular and two circular cutouts of metal sheet of negligible thickness are used to make a closed cylinder. The rectangular cutout ha a height of 18 cm. Each circular cutout has a radius of 5.2 cm. Calculate in terms of area of π, the surface
asked by kudu 
chemistry
Suppose 100 moles of a chemical is spilled into a lake. After 15.0 days, the total amount of the chemical in the lake 3.50 moles. Assuming that the reaction followed first order kinetics and no chemical was lost due to advection or volatilization, then
asked by danny 
chemistry
Based on reaction kinetics, which of the following pairs of reactions and reaction rate equations represent elementary reactions? You may choose more than one reaction. Ti + 2Cl2 = TiCl4 Rate = k[Ti][Cl2] 2SO2 + O2 = 2SO3 Rate = k[O2][SO2]2 Na2S + CuSO4 =
asked by danny