Monday

December 22, 2014

December 22, 2014

Total # Posts: 339

**Chemistry**

I'm stumped 4ko2 + 2co2 ----2k2co3 + 3o2 What mass of k02 in grams is required to react with 8.90 l at 22.0 c and 767 mm hg? Please help thank you
*December 15, 2014*

**Math**

Prove the identity: sec^4x - tan^4x = 1+2tan^2x
*November 10, 2014*

**chemistry**

in HNO3 titration, you add few drops of phenolphthalein indicator to 50.0 mL of acid in a flask. you quickly add 20.00 mL of 0.0547 M NaOH but overshoot the end point, and the solutions turn deep pink. instead of starting over, you add 30.00 mL of acid, and the solution turns ...
*September 27, 2014*

**chemistry**

Ok. Thanks.
*September 16, 2014*

**chemistry**

A small quantity of hydrochloric acid and a large quantity of limestone chips (CaCO3) are reacted on a beaker, which was placed on the pan of a balance. The mass of the beaker and its contents were recorded every half minute. (a) Write a chemical equation to show the reaction ...
*September 16, 2014*

**Geometry**

If EF= 10x+12, FG=14, and EG= 136, what is the value of x?
*September 11, 2014*

**chemistry**

For the electrolysis of molten potassium bromide: (a) write the equation for the reaction at cathode. (b) write the equation for the reaction at anode. (c) write the equation for the overall reaction.
*September 10, 2014*

**chemistry**

For the electrolysis of molten potassium bromide: Write the equation for the overall reaction.
*September 7, 2014*

**chemistry**

In the electrolytic refining of copper, write equation for the reaction of the impure copper.
*September 6, 2014*

**chemistry**

Write the anodic reaction for the electrolysis of concentrated zinc chloride solution. (a) Using plantium electrodes. (b) Using zinc electrodes
*September 6, 2014*

**chemistry**

Please I need help. Many,but not all, compounds are made up of positive and negative ions. Three positive ions A^+, B^2+ and C^3+ could form a total of six different compounds with negative ions, Y^2- and Z^3-. Derive the formulae for six compounds and write them in the table.
*August 28, 2014*

**chemistry**

How many moles of atoms are there in 32g of sulfur?
*August 15, 2014*

**chemistry**

Calculate the molarity of sulfuric acid if 25.00 mL of 0.095 mol L NAOH reacts with 26.45 mL of the acid.
*August 11, 2014*

**chemistry**

How many grams are there in 2.5 moles of CuSO4.5H2O?
*August 11, 2014*

**chemistry**

A 25 mL solution of nitric acid was placed in a flask and a few drops of phenolphthalein were added. Dilute sodium hydroxide was added util the indicator changed colour. It was found that 28 mL of the alkali was used. (a) What colour was the solution in the flask at the start ...
*August 7, 2014*

**maths**

A parallelogram has two adjacent sides of length 4cm and 6cm reapectively. If the included angle measures 52 degrees, find the area of the parallelogram.
*June 10, 2014*

**maths**

John wishes to determine the height of a flagpole. He takes a sighting of the top of the flagpole from point P. He then moves further away from the flagpole by 20 metres to point Q and takes a second sighting. Given the angle Q is 28 degrees and angle P is 53 degrees. Find how...
*June 7, 2014*

**maths**

An aircraft dropped a box of emergency supplies to a group of trampers. The height of the box above the ground, h, at time, t is given by the formula; h = 520 - 5t^2, where h is in metres and t is in seconds. Find how long it takes for the box to fall to the ground.
*May 26, 2014*

**maths**

Please I need help..how can I solve this guadratic equation?? 520 - 5t^2 = 0
*May 24, 2014*

**maths**

Solve this equation by completing squares and then check the solution.. x = 21/x-4
*May 20, 2014*

**maths**

a)Express y = 2 (x - 1) (x - 5) in the form y = ax^2 + bx + c. b) From the above quadratic equation calculate the following: I) x and y intercepts II) Coordinate of the turning point III) Is the graph a maximum or minimum turning point?
*May 20, 2014*

**maths**

An aircraft dropped a box of emergency supplies to a group of trampers. The height of the box above the ground, h, at time, t, is given by the formula: h = 520 - 5t^2 , where h is in metres and t is in seconds. Find how long it takes for the box to fall to the ground.
*May 19, 2014*

**maths**

Write without negative indices: a^-3b/c^-1
*May 19, 2014*

**maths**

Write 1/2^1-n in non- fractional form.
*May 19, 2014*

**maths**

Write as powers of 2. (a) 16 (b) 2^m/8
*May 19, 2014*

**maths**

Find the coordinates of the points of intersection of the straight line y = 3x - 6 with the parabola y = x^2 - 6x + 8 and solve Graphically.
*May 12, 2014*

**maths**

Given the quadratic equation y = -x^2 + 2x + 3. a) Will the graph turn upwards or downwards? b) What are the coordinates of x and y intercepts? c) What is the coordinate of the turning point? d) Use your answer in parts (a,b,c and d) to sketch the graph.
*May 10, 2014*

**maths**

2/ x^2 - 9xy^2 - 3/3x + 12y
*May 6, 2014*

**maths**

Simplify; x^2 - x - 6/ 6xy divide x^2 - 9/2x^2y
*May 6, 2014*

**maths**

Simplify; (x - y)^3 divide x^2z - 2xyz + y^2z
*May 6, 2014*

**maths**

Simplify 5x/7 × 15y/8x
*May 6, 2014*

**maths**

Simplify; p^2 - p - 42
*May 6, 2014*

**maths**

Solve this equation; p^2 - p - 42
*May 5, 2014*

**maths**

Solve this equation; p^2 - p - 42
*May 5, 2014*

**maths**

Simplify; x^2 + ax + bx + ab divide x^2 + 2ax + a^2.
*May 5, 2014*

**maths**

Simplify this expression; X^2 + ax + bx + ab/x^2 + 2ax + a^2
*May 2, 2014*

**maths**

Simplify 5x/7 × 15y/8x
*May 2, 2014*

**maths**

Solve this equation. 2/5 (x^2 + 1) = x
*May 2, 2014*

**maths**

Find the coordinates of the points of intersection of the straight line y = 3x - 6 with the parabola y = x^2 - 6x + 8. a) Graphically b)Prove your answer in (a) algebraically
*May 2, 2014*

**maths**

Given the quadratic equation y = -x^2 + 2x + 3. a) Will the graph turn upwards or downwards? b)What are the coordinates of x and y intercepts? c)What is the coordinate of the turning point? d)Use your answer in parts (a,b,c,and d) to sketch the graph.
*May 2, 2014*

**algebra**

How do you factor 2a^2+5x+3
*April 20, 2014*

**maths**

Write the equations below in the form y = mx + c. State how many solutions each systems of linear equation have. 3x = 6y 2y - 6x + 2 = 0
*April 19, 2014*

**naths**

What is the equation of the line which has gradient 2, and passes through midpoint of (3,4) and (5,6)
*April 19, 2014*

**maths**

What is the value of p if the line (3p + 1)x - 2y = 6p is perpendicular to the line 2x - y + 1 = 0
*April 19, 2014*

**maths**

Solve 2y - 5x = 3 and x + y = 5 using substitution.
*April 19, 2014*

**maths**

Show by calculations weather the following lines are parallel or not.. y + 5x = 1 and 0.2 = y - 5.
*April 16, 2014*

**maths**

Construct the table of values for the following equation 1 - 3x = 2y for -4<x <4. Use the answer to sketch the graph.
*April 16, 2014*

**math**

a recipe calls for 2 and 3/4 cups of milk. how many cups of milk written as a fraction greater than one are used in the recipe?
*March 6, 2014*

**Science**

If changing conditions lead to decreased oxygen levels in the stream, the carrying capacity of the stream for the trout will decrease. Oxygen level in water is therefore a(n) _____________ with respect to the number of trout that a particular stream can support.
*January 7, 2014*

**math**

One pump can empty a pool in 5 days, whereas a second pump can empty the pool in 7 days. How long will it take two pumps, working together, to empty the pool?
*November 18, 2013*

**physics**

A flower pot with a mass of 3.8kg is hanging by 2 wires that make an angle of 48° from the horizontal. what is the tension in each wire
*October 19, 2013*

**physics**

A flower pot with a mass of 3.8kg is hanging by 2 wires that make an angle of 48° from the horizontal. what is the tension in each wire?
*October 19, 2013*

**maths**

When the function f(x) is equal to 2xn + ax2 - 6 is divided by (x-1), the reminder is -7 and when divided by (x+3), the reminder is 129. Calculate the value of "a" and "n" and hence write the polynomial function completely.
*October 1, 2013*

**maths**

Calculate the arc length that subtends an angle of 55 degree at the centre of a circle with radius r = 5cm.
*September 1, 2013*

**maths**

The relationship between the vertical height and the horizontal distance of a ball thrown at 45 degree is given by the equation y = x - x^2/50, where y is the vertical height and x is the horizontal distance. (a) Find the maximum vertical height reached. (b) Find the ...
*September 1, 2013*

**maths**

The length of a rectangle is 10cm greater than its width. The perimeter of the rectangle is 1m. Find the simplest expression for the perimeter if the width is x.
*September 1, 2013*

**Maths**

Find dy/dx if y = 1/8.
*September 1, 2013*

**maths**

Does the parabola y = -3x^2 + 2x - 1 have a maximum or minimum value?
*September 1, 2013*

**maths**

Find the line that is perpendicular to y = -3/4 x + 2 and passes through (3,4).
*September 1, 2013*

**maths**

Sine and Cosine rule are both used in solving trigonometry problems.Give an example of when the cosine rule is more appliciable than the sine rule?
*September 1, 2013*

**maths**

Find the two stationary points on the curve when y = 2x/x^2 + 1
*September 1, 2013*

**maths**

A circle x^2 + y^ + 2x - 2y -1 = 0 expressed in the following form (x-h)^2 + (y-k)^2 = r^2 where h, k are the coordinates of the centre. How is r the radius given?
*September 1, 2013*

**maths**

A circle x^2 + y^ + 2x - 2y -1 = 0 expressed in the following form (x-h)^2 + (y-k)^2 = r^2 where h, k are the coordinates of the centre. How is r the radius given?
*September 1, 2013*

**Chemistry**

0.2 Faradays of electricity were passed through solutions of sulphuric acid. Calculate the volume of hydrogen evolved at s.t.p in sulphuric acid.
*August 24, 2013*

**Chemistry**

What would be the product formed for electrolysis of copper sulphate between the electrodes (a) Platinum (b) Copper and NaCl (aq) between (a)Platinum and (b) Copper electrodes?
*August 14, 2013*

**math**

what are the examples of exponetial notations
*August 12, 2013*

**maths**

Find the wind velocity if course 060 degree, airspeed 250km/h; track 040 degree, ground speed 260km/h.
*August 8, 2013*

**maths**

Find the course and ground speed if Track 150 degree, airspeed 400km/h; wind 040degree, 30km/h.
*August 8, 2013*

**maths**

Find the indicated term for (1-2x)^10, middle term.
*August 8, 2013*

**maths**

Find the ratio of the coefficients of the 4th and 6th terms in the expansion of (1 + 2x)^16
*August 8, 2013*

**chemistry**

This balance equation shows the burning of octane in air. 2C8H18 + 25O2 ----> 16CO2 + 18H2O. How many grams of carbondioxide will be produced when 1 mole of octane burns completely?
*August 8, 2013*

**maths**

Find the expansions of (1-x)^6 and (1+2x)^6 as far as the terms in x^3. Hence expand (1+x-2x^2)^6 up to the terms in x^3.
*August 8, 2013*

**maths**

The coefficient of x^2 is 69 in the expansion of (1-ax)^24, where a>0. Find the coefficient of x^3.
*August 8, 2013*

**maths**

Expand (1-x)^4. Hence find S if S = (1-x^3)^4 - 4(1-x^3)^3 + 6 (1-x^3)^2 - 4(1-x^3) + 1.
*August 6, 2013*

**maths**

In the expansion of (1-2x)^11 the coefficient of x^3 is k times the coefficient of x^2. Evaluate k.
*August 6, 2013*

**maths**

Expand (1-6x)^4 (1+2x)^7 in ascending powers of x up to and includeing the terms in x^3.
*August 6, 2013*

**maths**

In the expansion of (1-2x)^11 the coefficient of x^3 is k times the coefficient of x^2. Evaluate k.
*August 6, 2013*

**maths**

Expand (1+2x)^20 - (1-2x)^20) in ascending powers of x up to the term in x^5 and use this result to evaluate (1.02)^20 - (0.98)^20 to 3 significant figures.
*August 6, 2013*

**maths**

Obtain the binomial expansion of (2-x) (1+1/2x)^8 in ascending powers of x as far as the term in x^3. Use your result to estimate the value of 1.9 times (1.05)^8.
*August 6, 2013*

**Maths**

Pls help me to show that (1+root x)^5= 10 root x + 20x root x + 2x^2 ]oot x.
*August 5, 2013*

**chemistry**

1. In the following reactions, identify which reactants are the oxidizing agent and which are the reducing agents. a. 2S2O32- (aq) + I2 (s) ¨ 2I- (aq) + S4O62- (aq) b. NO3- (aq) + Zn (s) ¨ Zn2+ (aq) + NO2 (g)
*July 26, 2013*

**Chemistry**

A solution container was only label 0.005M. When phenolphthalene was added onto the solution, the color of the solution turned pink. After identifying the type of solution,it was later titrated with sodium carbonate. If the solution was sulphuric acid,determine the (a) [H...
*June 26, 2013*

**Chemistry**

Determine the [H+] when [OH-] is 2.0 times 10^-2 mole.dm-3.
*June 26, 2013*

**maths**

ABC is the segment of a circle with center O. This segment is enclosed in a rectangle APQC. Given that AC = 32 cm and AP = 8 cm, calculate; (a) The radius of the circle. (b) The angle AOC in both degrees and radians. (c) The area of the shaded region.
*June 20, 2013*

**Maths**

A surveyor measures the angle of elevation of the top of the mountain from a point (P) at sea level as 30 detre along a track which slopes uniformly uphill towards the mountain. From this point, which is 50 metre above sea level, he measures the angle of elevation as 40 degree...
*June 20, 2013*

**Chemistry**

Calculate the [H], [OH], pH and the pOH of this solution; 0.0025 M NaOH
*June 19, 2013*

**maths**

The position vector of the point A(3,4) relative to an origin O is a. (a) Express vector a or (OA) in terms of i and j. (b) Find the magnitude of a. (c) Find the unit vector in the direction of a.
*June 18, 2013*

**Maths**

ABC is the segment of a circle with center O. This segment is enclosed in a rectangle APQC. Given that AC=32cm and AP = 8 cm, calculate; (a) The radius of the circle. (b) The angle of AOC in both degrees and radians (c) The area of the shaded region.
*June 18, 2013*

**maths**

Expand (1-x)^4.Hence find S if S = (1-x^3)^4 - (1-x^3)^3 + 6(1-x^3)^2 - 4(1-x^3) + 1.
*June 18, 2013*

**maths**

Find two geometric progressions having: 54 as third term and 27/32 as ninth term.
*June 18, 2013*

**Maths**

Find the total amount required to pay off a loan of 16000 plus interest at the end of 8 years if the interest is compounded half-yearly and the rate is 14% p.a.
*June 18, 2013*

**Maths**

The third term of a sequence is 2(2/3) and the sixth term is 9. Find the first six terms when the sequence is; (a) arithmetic (b) geometric
*June 17, 2013*

**Maths**

Given the f (x) =2x^3 + ax^2 + bx - 9. (a)Find the value of a and b if f (x) has a factor x -3 but leaves a reminder of 8 when divided by x + 1. (b) Factorize f (x) completely and hence solve for x.
*June 17, 2013*

**maths**

If the nth term of a sequence is 3 x 2^n-1, Write down the first three terms.
*June 15, 2013*

**maths**

Find two geometric progression having: 2 as second term and 1458 as eight term,
*June 15, 2013*

**Chemistry**

One step of the Ostwald process for manufacturing nitric acid involves making nitrogen monoxide by oxidizing ammonia in the presence of a platinum catalyst: 4NH3 (g) + 502 (g)>> 4NO (g) + 6H2O (g). If the percentage yield is 80.3%, how many grams of NO can be produced ...
*June 10, 2013*

**Chemistry**

When 9.08 times 10^5 grams (one ton) of sodium chloride are electrolyzed in the commerical production of Chlorine, 5.24 times 10^5 grams of Chlorine are produced: 2 NaCl (aq) + 2 H2O (l) >>H2 (g) + Cl2 (g) + 2 NaOH (aq). Calculate the percentage yield.
*June 10, 2013*

**Chemistry**

When 9.08 times 10^5 grams (one ton) of sodium chloride are electrolyzed in the commerical production of Chlorine, 5.24 times 10^5 grams of Chlorine are produced: 2 NaCl (aq) + 2 H2O (l) >>H2 (g) + Cl2 (g) + 2 NaOH (aq). Calculate the percentage yield.
*June 10, 2013*

**MATHS - URGENT**

Write the expression in terms of sine only. 8(sin 2x − cos 2x)
*May 21, 2013*

**math**

tan(180-x)sin(360-x)cos90-x)cos(-x)/sin(x-180)cos(450+x)tan(180-x)
*May 19, 2013*