# Posts by victor

Total # Posts: 307

**chemistry **

Calculate the mass of marble chips that produce 20 grams of carbon (iv) oxide .when reacted with dilute hydrochloric acid (c=12,O=16,Ca=40)

**Chemistry**

A sample of Helium occupies 200 L at 30ºC under a pressure of 841 torr. What is the volume it occupies at standard temprature and pressure (STP)?

**Trigonometry**

How do you know where to plot the points of a cosine function on a graph? Is there a more simple way then plugging the x value into the calculator?

**math**

A model of a rectangular patio at a landscaping business will be enlarged by a scale factor of 2 when it is installed in a customer’s back yard. The area of the new enlarged patio will be 160 square feet. Which is the area of the landscaper’s model? 10 square feet 20...

**Physics**

A small, circular washer of radius a = 0.750 cm is held directly below a long, straight wire carrying a current of I = 13.0 A. The washer is located h = 0.495 m above the top of a table (see figure below). Assume the magnetic field is nearly constant over the area of the ...

**Chemistry**

whats the reaction?

**Chemistry**

How many liters of CO2 would be collected over water from the bomcustion of 35g of cyclohexane, if the gas is collected at a barometric pressure of 765 torr and a temperature of 303 K?

**Chemistry**

In a coffee cup calorimeter, 2.00 g of potassium hydroxide are mixed with 200.0 g of water at an initial temperature of 25.00?C. After dissolving the salt, the final temperature of the solution is 27.33?C. What is the heat change for the dissolution of potassium hydroxide in ...

**Chemistry**

So why is it 5/3 not 3/5 because P1V1=P2V2 right?

**Chemistry**

Thirty feet of water exert a pressure of 1 atm. Calculate the pressure (in kPa) exerted on a diver at a depth of 50 feet on a standard day.

**Chemistry**

A 30 g sample of water at 280 K is mixed with 50 g water at 330 K. Calculate the final temperature of the mixture assuming no heat loss to the surroundings.

**More Chem**

Consider the combustion of propane. Delta H is -2221 kJ. Assume all heat is from combustion of propane. What mass of propane must be burned in order to furnish this amount of energy assuming the heat transfer process is 60% efficient.

**Chem**

A 30 g sample of water at 280 K is mixed with 50 g of water at 330 K. Calculate the final temperature of the mixture assuming no heat loss to the surroundings.

**Chemistry Heat**

4Fe + 3O2 ---> 2Fe2O3 Delta H -1652 kJ How much heat is released when 10 g Fe and 2 g O2 are reacted.

**Chemistry**

So Ag+ + Cl- ---> AgCl and delta H is -65.5 kJ. I'm supposed to calculate delta H when one mole of AgCl dissolved in water, so 1 mol AgCl *(65.5 kJ/1mol Agcl) right? But the answer is 65.5 kJ, and why is it positive, not negative, is my question.

**Chemistry**

Ahh, that makes a lot of sense. Thanks.

**Chemistry**

The reaction Fe + Br2 ---> FeBr2 Delta H = -249.8kJ Calculate delta H when 10.0 g of FeBr2 is formed.

**CHEMISTRY**

Thanks. I see what I did wrong now, the T is 298 K not 273 K.

**CHEMISTRY**

How many liters of chlorine gas at 25C and 0.950 atm can be produced by the reaction of 24.0 g of MnO2 with hydrochloric acid? The products include manganese (II) Chloride, water, and chlorine.

**Chemistry**

You want to make 40 mL of gas from some aluminum carbonate. The temperature of the lab is 23 C and the rpessure is 760 torr. If you collect the gas over water, what mass of reactant is necessary?

**Chemistry**

What volume of gas can be produced in a lab where pressure is 16.0 psi and temperature is 25 C if you collect it over water from the reaction of 50g of ammonium sulfate with 50g of aluminum hydroxide. The equation for the reaction is: 3(NH4)2SO4 + 2Al(OH)3 ---> Al2(SO4)3 + ...

**Chemistry**

I know how to solve it using the ideal gas law, but how do you solve it using the combined gas laws?

**Chemistry**

What mass of zinc would need to react with hydrochloric acid in order to produce 25.0 mL of hydrogen gas collected over water at 25 degrees celsius and 105 kPa. How do you solve this using the combined gas laws? The answer is 0.067 grams but how do you get there?

**Chemistry**

So is it 475torr/2L = P2/3L?

**Chemistry**

Consider two flasks. What are the final partial pressure of H2 and N2 after the stopcock between the two flasks is opened? Assume the final volume is 3.00 L. What is the total pressure in torr? Flask 1: 2.00 L H2, 475 torr Flask 2: 1.00 L N2, 0.200 atm Imagine two round flasks...

**chemistry**

Thanks

**Chemistry**

Also, I just noticed, the delta H for NaOH is for the standard enthalpy of formation, which is different from the enthalpy change of the reaction. If 57.2 was meant to be the enthalpy change of the reaction, then just convert to J, and substitute 57200J instead of 71500J. **...

**Chemistry**

First of all, since it's 0.250 M and 50 mL for both reactants, you don't really need to know the equation since both are limiting reactants, but you put that delta H is 57.2 Kj/mol of NaOH. So I'm guessing that NaOH is the other reactant, anyways HCl plus NaOH is a...

**Science**

The sun and Earth both have breathable air

**English**

#2 means #4

**physics**

In using a pulley system, an effort of 100N is needed to raise steadily a load of 800N (a) what is the mechanical advantage?. Data effort=100N load=800N M.A=load/Effort M.A=800N/100N M.A=8

**physics**

How much work isneeded to stop a 20g bullet moving with a speed of 150m/s

**Chemistry**

A is a solution of hydrochloric acid containing 3.650g of HCl in 1dm3 of solution. B is a solution of impure sodium carbonate. 25cm3 of B require 22.7cm3 of A for complete reaction. Given that 5.00g of impure B was dissolved in1dm3 solution,what is the percentage by mass pf ...

**Math**

The shipping clerk packs a cube with side lengths of 8 inches into a box with side lengths of 10 inches. What is the volume of the space left in the larger box for packing materials?

**math**

A baseball diamond is a square with each side 90 feet long. What is the straight-line distance from third base to first base? (Round your answer to the nearest tenth.)

**math**

The north wall of a barn is a rectangle 25 feet high and 60 feet long. There are five windows in the wall, each 8 by 10 feet. If a gallon of paint will cover 275 ft2, how many gallons of paint must the painter buy to paint the wall?

**Physics **

a boat sails 150km N60°E, then 100km West. What is it's displacement from its starting point?

**riddle**

Money

**kelvin**

P,Q and R are points on the same horizontal plane .the bearing of Q from P is 150° and the bearing of R from Q is 060°. if |PQ| =5m and |QR|=3m find the bearing of R from P correct your answer to the nearest degree

**civic education**

limitation of human right

**MATH**

IF LOG10 A=4,WHAT IS A?

**Chemistry**

A minimum energy of 151 kJ is required to dissociate a mole of iodine molecules, I2. Calculate the wavelength of radiation that supplies this energy, assuming each bond beaks by absorbing one photon.

**Science**

Which is the molarity of a solution containing 20 g of CH3 OH in 300 mL of solution

**Math**

Every Wednesday is salad bar day at Ashley's school. The most popular ingredients are cherry tomatoes, cucumber slices, and shredded carrot. Last Wednesday, out of the 27 students in Ashley's class- 14 took carrot 13 took cucumber 16 took tomato 8 took cucumber and ...

**physics**

A car travels 20 km southwards and then another 30 westwards. What is the displacement of the car from its initial position?

**math**

12,b,75 are consecutive terms of a geometrical sequence what is the common ratio?

**Physics**

An unknown substance at a temperature of 20 degrees Celsius is warmed up to 50 degrees when water at 80 degrees is added to it. Can I post this question. There is more information I have and the point is to find the specific heat of the unknown substance.

**linear algebra**

A signal lac has six flags of which 1is blue ,two z white,3 ar red.it sends messages hostin flags in a flagpole.d messages ar being conveyed by d order in which d colours ar arranged find hw many mesaages it can send.......a.using exactly six flags,b.using exactly five flags

**PHYSICS**

What is the potential energy of a 150 kg diver standing on a diving board that is 10 m high?

**Chemistry**

Calculate the concentrations of Cd2 +, [Cd (CN) 42] and CN at equilibrium when they dissolve 0, 42mol of Cd(NO3)2, molarity= 2.50 M Kf =7.1x10^16

**Physics**

A 900-kg merry-go-round (a flat, solid cylinder) supports 10 children, each with a mass of 50.0 kg, located at the axis of rotation (thus you may assume the children have no angular momentum at that location). You need to describe a plan to move the children such that the ...

**Maths**

A box is made of wood 5cm thick, its internal dimension are 10cm by 8cm by 11cm, what is the volume of the wood in the box

**life orientation**

Describe the three human rights violations or discriminations you selected and give at least two examples of such violations you found in your research

**life orientation**

Guys am in deep trouble pls hlp

**Math**

a man drives 30 miles in 2 hours. how many miles he will drive in 8 hours?

**Physics**

A truck is moving away at 30 mph from a car moving towards the truck at 60 mph. If the truck emits a horn of frequency 500 Hz, what frequency does the driver of the car hear to 3 significant digits? how do i solve i know the answer is 519hz but how?

**Math**

Sandra is traveling 17 mph on her bicycle. After 4 hours, how far will she have traveled

**Science**

-10kJ because you have to consider the work due the H2 (-6,7kJ) and the work due the O2 produced (-3.3kJ) in the reaction.

**Maths**

A sector of a circle of radius 7cm subtending an angle of 270 degree at centre of the circle is use to form a cone? (A)find the base radius of the cone. (B)calculate the area of the base of the cone.

**Physis**

245m

**chem**

a) Co(H2O)6^2 + 4 Cl^‐1 (aq) ⇄ CoCl4^‐2 (aq) + 6 H2O (l) Rewrite the net ionic equation above including the energy term where appropriate. The Delta H for this reaction is +50 kJ/mol. b) Silver chloride (AgCl) is a white solid. For the equilibrium reaction ...

**Math**

how do you solve? kim's mom is 47 years old. in 5 years her mother will be 10 years older than twice what kim's age will be. how old is kim now?

**Physics**

A voltmeter is specified as being accurate to within 2%. The reading on the voltmeter is 3.50v..the maximum voltage represented by this reading is?

**algebra1**

okay than bye

**algebra1**

hey look i need help !

**algebra1**

can you help me ?!

**algebra1**

What if they are diffrent people !

**algebra1**

umm idk who u are taking about

**algebra1**

im sorry what are u taking about

**algebra1**

Melissa wants to figure out how many fish live in a small lake by her house .She ccatces 15 fish and tags the (safely).Shethen outs thoes fish back in the lake .Then next day ,she catches 28 fish .of those 28 fish, 3 of them have the tags on them.About how many total fish live...

**Algebra**

i mean zoe is my sis

**Algebra**

my beother is victor

**Algebra**

ok!

**Algebra**

Thanks !

**physics**

The brass bar and the aluminum bar in the drawing are each attached to an immovable wall. At 21.3 °C the air gap between the rods is 1.70 x 10-3 m. At what temperature will the gap be closed?

**physics**

A person who weighs 717 N is riding a 80-N mountain bike. Suppose the entire weight of the rider plus bike is supported equally by the two tires. If the gauge pressure in each tire is 8.10 x 105 Pa, what is the area of contact between each tire and the ground?

**physics**

The Eiffel Tower is a steel structure whose height increases by 19.0 cm when the temperature changes from -9 to +41 oC. What is the approximate height (in meters) at the lower temperature?

**basic programming principles**

2.Write only the select case statements for the following problem statement. The marital code of a person is stored in the variable called marCode. Display the corresponding description on the screen. Provide for an incorrect marital code Marital Code S Single D Divorced M ...

**science help**

noble gases and group4, period6

**Overdue Science Lesson, Very Urgent.**

This is why we have google.

**Written Communication**

At the library, the quickest way to locate varied, reliable information for your research paper is to A. check the encyclopedias. B. search the card catalog for related titles. C. ask the reference librarian. D. check the Readers' Guide.

**grovment**

The Electoral College was included in the Constitution primarily because the Framers believed that __________. political parties might be regulated by the government the general public might be swayed by a charismatic leader cooperation between the executive and legislative ...

**math problem (please help)**

hey r u single

**statistics**

40

**business maths**

Jennifer owes $13,000 to a friend who is charging her interest of 0.90% p.m. She is required to settle the amount owed with two equal payments, one today and the other in three months. Calculate the size of the payments using three months as the focal date. I am totally lost...

**physics**

A mass is thrown upward towards a vertical wall. If the release point is at a horizontal distance of 12 meters from the base of the wall, and the ball is launched at an angle of 60 degrees above the horizontal, with what speed need it be thrown so that it strikes the wall 10 ...

**math**

To find three numbers in geometric progression, knowing that their sum is 78 and the highest 30 units exceeds the sum of the first and second term.

**math**

Given the numbers 10 and 40 their averages are obtained by different procedures 16, 20 and 25 respectively. Say which is the arithmetic mean and what is the geometric mean

**math**

A cooling cost 1540 dollars. After four years he sold at half their value. If this is repeated every four years, the payment in the refrigerator the fifth person to buy it and after a few years this purchase was made.

**math**

Finding three geometrically numbers knowing that their sum is greater than 78 and 30 units exceeds the sum of the other two.

**math**

The answer is B

**Physics**

Calculate the escape velocity of a satellite launched from the earth surface if the radius of the earth is 6.4x10^6m

**physics**

It the specific gravity of mercury is 13.6 and the atmospheric pressure is 70cm of mercury, what is the total pressure of the gas supply in cm of water if the height of water is increase by 3cm?

**Finance**

What is the coupon rate of a two-year, $10,000 bond with semiannual coupons and a price of $9,543.45, if it has yield to maturity of 6.8%?

**Fiance**

What must be the price of a $10,000 bond with a 6.5% coupon rate, semi-annual coupons, and two years to maturity if it has a yield to maturity of 8% APR?

**Finance**

If $12,000 is invested in a certain business at the start of the year, the investor will receive $3,600 at the end of the next four years. What is the present value of this business opportunity if the interest rate is 7% per year?

**math**

The first term of an AP is 8. The ratio of d 11th term to the 7th term is 5:8 calculate the common difference

**Differential Equations**

A college professor contributes $5,000 per year into her retirement fund by making many small deposits throughout the year. The fund grows at a rate of 7% per year compounded continuously. After 30 years, she retires and begins withdrawing from her fund at a rate of $3,000 per...

**LIFE ORIENTATION**

Because they want student know about their career

**Science**

Acetylene gas c2h2 reaction cac2+2h2o. C2h2+Ca(oh)2 how many moles of cac2 needed to prepare 10.0 g c2h2 please show work and answer soon final question on big test review