Saturday

February 13, 2016
Total # Posts: 1,926

**chemistry**

When NH4NO3 is dissolved in water, it dissociates into its ions, followed by a temperature drop: NH4NO3 -> NH4+ + NO3- (though it's not really that relevant though ^^;) Anyway, the heat gained or lost can be calculated using the formula Q = mc(T2 - T1) where m = mass (...
*November 23, 2013*

**pre-algebra**

Are you sure the first term is w^2 or w^3? Anyway, if it's w^3, w^3 + 4w^2 - 4w = 16 w^3 + 4w^2 - 4w - 16 = 0 w^2(w + 4) - 4(w + 4) = 0 (w^2 - 4)(w + 4) = 0 (w + 2)(w - 2)(w + 4) = 0 w = -2 w = 2 w = -4 Hope this helps :3
*November 22, 2013*

**Calculus Area between curves**

Actually your answer is correct if it's indefinite integral. :) Now that you got the answer, we can now evaluate it at the given bounds: -(1/3)(8-2x)^(3/2) , at x = -7 to 0 = -(1/3)(8-2(0))^(3/2) - [-(1/3)(8-2(-7))^(3/2)] = -(1/3)(8)^(3/2) - [-(1/3)(22)^(3/2)] = (22/3)*(22...
*November 22, 2013*

**Science**

Yes.
*November 22, 2013*

**Science**

Red has the longest wavelength, while violet has the shortest. Arranging the colors from shortest to longest wavelength: VIBGYOR
*November 22, 2013*

**cal**

f(x) = x^2 + √x We can rewrite this as: f(x) = x^2 + x^(1/2) Therefore, the first derivative is f'(x) = 2x + (1/2)*(x^(-1/2)) And the second derivative is f''(x) = 2 + (-1/4)*(x^(-3/2)) Hope this helps :3
*November 22, 2013*

**chemistry**

Let m = mass of NaCl in grams Since the given is in 22% mass/mass, 0.22 = m / 250 m = 0.22 * 250 m = 55 grams NaCl Hope this helps :3
*November 19, 2013*

**Geometry (math)**

I suggest you draw the figure, it's easier to see that way. The planes that intersect are: (1) the plane containing the cross-sectional area (one triangle) and the plane containing one lateral surface area (one rectangle); and (2) the planes containing two lateral surface ...
*November 18, 2013*

**math**

cot x - tan x = 2 cot 2x I will be solving the left side and make it look like the right side. Note that cot x = cos(x) / sin(x) and tan x = sin(x) / cos(x): cos(x) / sin(x) - sin(x) / cos(x) Combining, cos^2 (x) - sin^2 (x) / cos(x)*sin(x): Note that the numerator cos^2 (x...
*November 18, 2013*

**science**

Recall that speed is distance travelled over a certain period of time, or v = d/t Since we know the distance (5000 m) and the speed (25 m/s), we can solve for the time: 25 = 5000/t 25t = 5000 t = 5000/25 t = 200 s Hope this helps :3
*November 15, 2013*

**science**

Acceleration is the change in velocity over a certain period of time, or a = Δv / t Substituting, a = (3 m/s) / 4 s a = 0.75 m/s^2 Hope this helps :3
*November 15, 2013*

**Trigonometry**

It would be a lot easier if you draw the figure. What you would do is just a summation of Forces. Since the system is at equilibrium (forces cancel out), the sum of forces should be zero. Sum of forces at x-direction: (T1)*cos(28) - (T2)*cos(35) = 0 Sum of forces at y-...
*November 15, 2013*

**Algebra**

If you mean ln (x) = negative number, yes, they can. If you mean ln (negative number) = y, no it's not possible. If you plot ln x, the plot is asymptotic to y-axis from the right (positive values of x only), therefore the plot will never reach x equal to zero nor the ...
*November 15, 2013*

**Math**

The area of circle is given by, A = pi*(D^2)/4 where D = diameter Substituting, A = ( 3.14 * (5/2)^2 )/4 A = 4.90625 ft^2 In mixed number, this is 4 29/32 ft^2. Hope this helps :3
*November 14, 2013*

**math**

Solve for w: 100w + 10000 = 220w + 7000 100w - 220w = 7000 - 10000 -120w = -3000 w = 3000/120 w = 25 weeks hope this helps :3
*November 14, 2013*

**Geometry**

Concurrent lines are lines that intersect at a single point. Well, a figure cannot be shown here, but try to draw/imagine. For instance, in an x-y plane, you have the three concurrent lines that intersect at the origin. Now, in order to have one pair of parallel lines, the ...
*November 14, 2013*

**math**

Let x = length. Do ratio & proportion: 10 / 19 = 38 / x Cross-multiplying, 10x = 19 * 38 10x = 722 (10/10)x = 722/10 x = 72.2 in Hope this helps :3
*November 14, 2013*

**physics**

I suggest you draw the figure. Note that if you draw the figure, you'll have a scalene triangle (a triangle with no sides equal). Two of its sides are given (51 and 45), and the angle between them is 180 - 30 = 150 degrees. Since you have two given sides and an angle ...
*November 14, 2013*

**science**

Thus, it's a rational number. Note that integer and whole number are the same.
*November 14, 2013*

**physics**

If x is the displacement, note that v (velocity) = dx/dt, and a (acceleration) = dv/dt Therefore, we get the derivative of the given equation: dx/dt = 6t - 3t^2 = velocity Note that this is just the equation for velocity, and we need to maximize it. Thus, we differentiate it ...
*November 14, 2013*

**Pre-Calculus**

D = √(x^2 + 8x + 12) We can also rewrite this as D = (x^2 + 8x + 12)^(1/2) Now we have to get dD/dt. To get the derivative, recall that if x is raised to a certain constant, the derivative is x^n = n*x^(n-1) * dx We multiply the exponent to x, which is jow raised to 1 ...
*November 12, 2013*

**chemistry**

Assuming the gas is ideal, we use the ideal gas law: PV = nRT where P = pressure V = volume n = number of moles R = universal gas constant T = temperature Note that there are two different species involved, but their P and T are the same (of course, R also). Rewriting the ...
*November 12, 2013*

**chemistry-correction**

*In the second one, I mean you don't usually make solutions of defined volume and concentration in beakers, because these glasswares are not accurate in volume. (sorry about this, I misread ^^;) Also, using volumetric pipettes or simply pipettes are more accurate than ...
*November 12, 2013*

**chemistry**

The dilution formula is M1*V1 = M2*V2 Substituting, 0.02 * 100 = 0.4 * V2 V2 = 2 / 0.4 V2 = 5 mL The volume of stock solution used is correct. And we need 95 mL of water to make the target solution. One mistake here is adding water to acid. Note that you should NOT add WATER ...
*November 12, 2013*

**CHEMISTRY**

Yes it does. From the problem, it says that 50 cm^3 of AgNO3 and 50 cm^3 of HCl are mixed. Therefore, the total volume of the solution is 50 + 50 = 100 cm^3. Then an assumption is that the density of the solution is 1 g/ cm^3. We have the volume, we have the density, we can ...
*November 12, 2013*

**math**

a. I'm not sure about this ^^; sorry. b. We add the number of steps to each coordinate. The initial point is (-2,-5). Here, the x-coordinate is -2 and the y-coordinate is -5. When the drummer moved: 1 step right means plus one to the x-coordinate 3 steps up means plus ...
*November 12, 2013*

**algebra**

Let n = cost of refreshments for 26 people. We can do ratio and proportion here. For every 18 people, the cost of refreshments is $45, while for every 26 people, the cost of refreshments is $ n. Thus, 18 / 45 = 26 / n We cross-multiply: 18n = 45 * 26 18n = 1170 Divide both ...
*November 12, 2013*

**Math-Algebra**

The pressure of a gas varies directly as its temperature: P = kT Note that the temperature must be absolute (in Kelvin units). To convert, just add 273 to the degree Celsius. Substituting the given, 200 lb/in^2 = k (65.5 + 273) k = 200 / 338.5 k = 0.5908 Now that we know the k...
*November 11, 2013*

**Math - Algebra**

Are you sure it's 81.5 N on the surface of the moon? #1. Anyway, what we'll do is first get the mass of the man. Note that mass is constant, and in physics, it is different from the term 'weight' (though in other cases, they are interchangeable, like in ...
*November 11, 2013*

**math**

Because it lies in the x axis.
*November 11, 2013*

**math**

Substitute the pints to the function: at (0,b): f(x) = 2^x / a b = 2^0 / a b = 1/a at (2,0.8): f(x) = 2^x / a 0.8 = 2^2 / a 0.8 = 4 / a a = 4 / 0.8 a = 5 Substituting to the equation for b, b = 1/a b = 1/5 Hope this helps :3
*November 10, 2013*

**Chemistry**

This is a colligative property problem. Note that when an solute is dissolved in a solvent, the freezing point of the solvent decreases. This is called freezing depression, and the change in temperature can be calculated by (T,orig - T,new) = Kf * m where T,orig = original ...
*November 10, 2013*

**maths**

But where does the 1.15 p come from
*November 9, 2013*

**Math!**

Yes it is.
*November 7, 2013*

**chemistry**

Recall that the formula for root mean square speed is given by v,rms = (3RT/M)^(1/2) where R = universal gas constant = 8.314 J/mol-K T = temperature in K M = molar mass in kg/mol We know that the molar mass of O2 is 32 g/mol or 0.032 kg/mol, and the v,rms is equal to 475. ...
*November 5, 2013*

**math**

What does that ' mean? Does it mean that the x is raised to a certain power? If it does, f(x) = 3x^3 - 4x^2 + 2x + 555 Substitute x = -5 to the function: f(-5) = 3(-5)^3 - 4(-5)^2 + 2(-5) + 555 f(-5) = -375 - 100 - 10 + 555 f(-5) = 70 hope this helps :3
*November 5, 2013*

**chemistry**

Assuming the gas is ideal, we can use the Ideal Gas Law: PV = nRT where P = pressure in atm V = volume in liters n = number of moles R = universal gas constant = 0.0821 L-atm/mol-K T = temperature in Kelvin Useful units conversion: 1 atm = 760 torr Kelvin = Celsius + 273 The ...
*November 5, 2013*

**chemistry**

Assuming the gas is ideal, we can use the Ideal Gas Law: PV = nRT where P = pressure in atm V = volum in liters n = number of moles R = universal gas constant = 0.0821 L-atm/mol-K T = temperature in Kelvin We know V, T and of course, R. To convert degree Celsius to Kelvin, we ...
*November 5, 2013*

**math**

What you'll do is add 3 and 8 to get the total: 3 + 8 = 11 Now we divide the total number of students by 11: 132/11 = 12 (this is the multiplier for 3 and 8) Therefore, 3 * 12 = 36 students (prefer baseball) 8 * 12 = 96 students (prefer soccer) Hope this helps :3
*November 5, 2013*

**math**

What you'll do is add 3 and 8 to get the total: 3 + 8 = 11 Now we divide the total number of students by 11: 132/11 = 12 (this is the multiplier for 3 and 8) Therefore, 3 * 12 = 36 students (prefer baseball) 8 * 12 = 96 students (prefer soccer) Hope this helps :3
*November 5, 2013*

**Math check answers plz**

It's 16.67 %. Note that there are six numbers in a dice, and in one roll, the probability of getting a six is 1/6 or 16.67%.
*November 4, 2013*

**chemistry**

NiCl2(aq) + 2NaOH(aq) → Ni(OH)2(s) + 2NaCl(aq) First get the number of moles of NaOH. Recall that molarity is moles of solute per liter of solution: M = n / V Getting n, n = MV n = (0.6)(0.025) n = 0.015 mol NaOH To get the mol Ni(OH)2, we multiply the mol of NaOH to the...
*November 4, 2013*

**Math**

Yes, it's 16. :)
*November 4, 2013*

**Algebra**

25u^2 - 81 This is a difference of two squares. Therefore, the factor is (5u - 9)(5u + 9) hope this helps :3
*November 4, 2013*

**Algebra**

20 v^7 u^3 16 x^6 v^4 u^5 GCF of 16 and 20: 4 GCF of v^7 and v^4 : v^4 GCF of u^3 and u^5 : u^3 Thus, the GCF is the product of the three, which is equal to 4 v^4 u^3. hope this helps :3
*November 4, 2013*

**math**

To get the slope we use the formula: m = (y2 - y1) / (x2 - x1) where (x1,y1) and (x2,y2) are the points. Substituting, m = (4 - (-1)) / (3 - 2) m = (4 + 1) / 1 m = 5 (a) Note that parallel lines have equal slope. Thus slope of the parallel line is also equal to 5. (b) Note ...
*November 4, 2013*

**ms. sue please help**

Change first the 12 1/2 into improper fraction: 12 1/2 = (12*2 + 1)/2 = 25/2 Then we divide 50 by 25/2 to get the rate per hour: 50 / (25/2) 50 * 2/25 100/25 = $4 per hour I'm not Ms. Sue but I hope you can trust my answer. Hope this helps :3
*November 4, 2013*

**math check**

Instead of multiplying 14.6 by 2, you should have divided it by 2.
*November 4, 2013*

**chemistry**

Recall that molarity is just moles of solute per liter of solution: M = n / V Since we're given the volume and molarity, we solve for the n: 0.30 M = n / 0.15 L n = 0.3 * 0.15 n = 0.045 mol CH3OH The problem asks for the mass of CH3OH. To get the mass, we multiply the ...
*November 4, 2013*

**Math**

1. Yep 2. You would have to multiply 15% by 38, because it's asking for the number of students who did NOT pass their test. 38 * 0.15 = 5.7 or approximately equal to 6 students 3. Let n be the sales price It was said that 52% or 0.52 of the sales price is the profit. Thus...
*November 4, 2013*

**honormath3**

-(35/4 * 3/7) / (-4/3) -(105/28) / (-4/3) -105/28 * (-3/4) 315/112 = 45/16 hope this helps :3
*November 4, 2013*

**college algebra**

ln y = log 9 e^(ln y) = e^(log 9) y = e^(0.9542) y = 2.5967
*November 4, 2013*

**college algebra**

ln y = -0.35 e^(ln y) = e^(-0.35) y = e^(-0.35) y = 0.7047
*November 4, 2013*

**math**

We must change first the 2 1/2 to improper fraction: 2 1/2 = 5/2 then we divide: 5/2 / (1/4) 5/2 * 4/1 20/2 = 10 people hope this helps :3
*November 4, 2013*

**Math**

We divide the area by the width to get the length: L = (x^2 - 5x - 10) / (x + 2) I don't think this can be simplified further. hope this helps :3
*November 4, 2013*

**Math Can someone check my answers ?**

Yes. ;)
*November 3, 2013*

**Math Can someone check my answers ?**

Yes it's B. Though the term surface area is for 3D shapes. But I guess it's fine, since it's still area anyway. ^^
*November 3, 2013*

**Math Can someone check my answers ?**

Are you sure it's "surface area" and it's "circle"? Because usually if the shape is 2D, the term is 'area' only. If it's "area of a circle" only, A,circle = pi*r^2 A,circle = 153.9 in^2 (closest to letter B) If it's "...
*November 3, 2013*

**Math**

#1. I'm not sure if you mean x - sqrt(x-2) = 4 or x - sqrt(x) - 2 = 4, but I'll go with the first. x - sqrt(x-2) = 4 To do this, we isolate the term with squareroot to one side of equation: x - 4 = sqrt(x-2) Then we square both sides and solve for x: (x - 4)^2 = (sqrt(...
*November 3, 2013*

**Math**

Hi. I've seen your previous post. I'll try answering them. :) (9n+1)squared = 9 We expand the term with the square: (81n^2 + 18n + 1) = 9 81n^2 + 18n + 1 - 9 = 0 81n^2 + 18n - 8 = 0 Factoring, (9n + 4)(9n - 2) = 0 n = -4/9 and n = 2/9 Note that there are two values of ...
*November 3, 2013*

**Math**

(9n+1)squared = 9 We expand the term with the square: (81n^2 + 18n + 1) = 9 81n^2 + 18n + 1 - 9 = 0 81n^2 + 18n - 8 = 0 Factoring, (9n + 4)(9n - 2) = 0 n = -4/9 and n = 2/9 Note that there are two values of n. The sign that looks like a check mark in #2 is a squareroot sign. I...
*November 3, 2013*

**SAT math**

formula for slope: m = (y2 - y1)/(x2 - x1) where (x1,y1) and (x2,y2) are the points on the line. Substituting, -3/5 = (4 - 1)/(1 - x) -3(1-x) = 5(3) -3 + 3x = 15 3x = 18 x = 6 hope this helps :3
*November 2, 2013*

**Math**

p^2 - q^2 = 12 p + q = 4 We have two equations and two unknowns, so we can solve for the values of p and q. What we'll do is substitution. We choose one equation, and choose one variable and express it in terms of the other variable. In this case, we choose the second, and...
*November 2, 2013*

**Math**

That's correct. :) formula for slope: m = (y2 - y1)/(x2 - x1) where (x1,y1) and (x2,y2) are the points on the line. Substituting, -3/5 = (4 - 1)/(1 - x) -3(1-x) = 5(3) -3 + 3x = 15 3x = 18 x = 6 hope this helps :3
*November 2, 2013*

**math**

We just solve it like a real equation. Though remember that when a negative number is multiplied or divided to both sides of equation, the sign is reversed. 3(3F − 3) > 4F − 5 9F - 9 > 4F - 5 9F - 4F > 9 - 5 5F > 4 F > 4/5 Hope this helps :3
*November 2, 2013*

**6th grade math**

1. It's actually 2a - 18 2. Yep 3. Yep 4. Yep 5. Yep 6. Yep 7. Yep 8. Yep 9. Yep 10. I guess it's okay 11. Yep 12. Yep 13. 2^4 = 16 ; (the base 2 stands for the 2 people and 4 is the number of rounds) 14. Hmmm, "four multiplied by the sum of nine and twenty-three&...
*November 1, 2013*

**math**

x^2 - y^2 - 2y - 1 x^2 - (y^2 + 2y + 1) x^2 - (y+1)^2 (x - (y+1)) (x + (y+1)) (x - y - 1)(x + y + 1) Hope this helps :3
*November 1, 2013*

**algebra 2**

2(x-5) >= 6(x-3) 2x - 10 >= 6x - 18 2x - 6x >= 10 - 18 -4x >= -8 x <= 2 Hope this helps :3
*November 1, 2013*

**MATHS**

fifth of one and a quarter: (1/5)*(1 1/4) = (1/5)*(5/4) = 1/4 one and a quarter: 1 1/4 = 5/4 adding them, 1/4 + 5/4 = 6/4 = 3/2 = 1 1/2 Hope this helps :)
*November 1, 2013*

**chemistry**

I am not sure if you have a typo, but for the reaction to be balanced, that should be Nitrous Acid (HNO2) in the reactant side: 3HNO2 -> HNO3 + H2O + 2NO Note that all the species here are neutral (zero charge). Thus the sum of the individual charges of each element ...
*November 1, 2013*

**Algebra**

I've never encountered this AC method before, but I've tried to google it. It's easy though it's crazy. XD Anyway, #1. I'll change the variable into x so it won't be confusing: 2x^2 + 3x + 1 First step is to multiply a (the numerical coeff of x^2) by c...
*October 31, 2013*

**Math HELP URGENT!**

A. Factors of denominators: (x^2-z^2) = (x+z)(x-z) (x^2-2xz+z^2) = (x-z)(x-z) Thus, LCD : (x+z)(x-z)(x-z) B. Factors of denominators: (x^2-64) = (x-8)(x+8) (40-5x) = -5(x-8) x = x Thus LCD : -5x(x-8)(x+8) Hope this helps :3
*October 31, 2013*

**Math-correction**

*lol I'm sorry the smaller time is t = 4s. OMG XD
*October 31, 2013*

**Math**

To get the time, we just substitute h = 592 to the equation: h = 212t - 16t^2 592 = 212t - 16t^2 16t^2 - 212t + 592 = 0 4t^2 - 53t + 148 = 0 Factoring, (t - 4)(4t - 37) = 0 t = 4 s t = 37/4 s Since it requires the time in which the rocket FIRST reaches a height of 592, we ...
*October 31, 2013*

**algebra**

We just solve it like a real equation. But then, if you multiply or divide a negative number on both sides, the sign will be reversed. 4 - 3w >= 8 -3w >= 8 - 4 (-3w)/(-3) >= 4/(-3) w <= -4/3 Hope this helps :3
*October 31, 2013*

**Geometry**

Use cosine (let x = angle): cos (x) = 3/12 Solve for x.
*October 31, 2013*

**Math**

1. Yep 2. The more complete set would be A. 3. Yep 4. It's actually D. Note that to say that a number is divisible by 9, the sum of the digits should be divisible by 9. Here, 5229 : 5+2+2+9 = 18, and 18 is divisible by 9. Hope this helps :3
*October 31, 2013*

**Math...help**

A & B are correct. In C, the (-) sign should be (+) because 12 minus 9 is positive 3. In D, combine the constants: 8 + 6d - 12 = 6d - 4 In E, combine the terms with variables: 30e + 18 - 8e = 22e + 18 In F, 15f + 10 - f - 5 = 14f + 5 hope this helps :3
*October 31, 2013*

**math**

Use the pythagorean theorem: c^2 = a^2 + b^2 where c = hypotenuse a = one leg b = the other leg In the problem, a = 9 b = 12 Now solve for c using the equation above.
*October 31, 2013*

**math**

If a point is reflected over the y-axis, the y-coordinate of the new point is equal to the original, while the x-coordinate is the negative of the original. Therefore, if the point is (8, -10), the reflected point is at (-8, -10). Hope this helps :3
*October 31, 2013*

**Math**

The conversion is 1 yard = 3 feet. Thus, 1 yd^3 = 3^3 ft^3 or 27 ft^3 If there are 3 yards, 3 yd^3 = 3 * 27 ft^3 = 81 ft^3 You're correct. :)
*October 31, 2013*

**math**

Recall that are of triangle is just A = (1/2)bh where b = base h = height It was said that the base is half of the height, or b = (1/2)h. Substituting to the formula, A = (1/2)(1/2)h*h 121 = (1/4)*h^2 484 = h^2 h = 22 m Solving for the base, b = (1/2)*22 = 11 m Hope this helps...
*October 31, 2013*

**Substituion MATH**

It's wrong, I don't know how you checked but x = 32 and y = 6 actually doesn't satisfy either given equation. Anyway, okay let's do #2. -1/2x - 1/4y = 3 1/3x + 1/6y = 2 To deal with fractions, it's easier if you first make them whole numbers by multiplying ...
*October 31, 2013*

**Substituion MATH**

#1. -x + 10y = 60 -4x + 16y = 32 If we need to use the substitution method, we choose an equation and let one of the variable in terms of the other. Then we substitute it to the other equation. Here, let's choose the first equation. -x + 10y = 60 Then let's choose the ...
*October 31, 2013*

**math (please help)**

#1. Note that horizontal line has a zero slope, and in the form y = c, where c is a any real number. Therefore, if it passes thru the point (-8,8), the equation must be y = 8. #2. If we are given the two points on the line, we first get the slope using the formula m = (y2 - y1...
*October 31, 2013*

**math**

Let A = cost of one apple Let P = cost of one ponkan According to the first statement, 4A + 2P = 53 According to the second statement, 2A + 4P = 75 Now we're looking for 6A + 6P (because half a dozen is equal to six). Notice that if we add the equations, we'll get 6A...
*October 31, 2013*

**8th grade chemistry**

C. NaHCO3 It actually contains 6 atoms. :3
*October 31, 2013*

**Geometry**

#1. I believe there should be a given figure... #2 & #3. We need the choices...
*October 29, 2013*

**Calculus**

Get the derivative with respect to x: f(x) = -2x^3 + 33x^2 - 108x + 2 f'(x) = -6x^2 + 66x - 108 Let f'(x) = 0 and get the values of x: 0 = -6x^2 + 66x - 108 0 = x^2 - 11x + 18 0 = (x - 2)(x - 9) x = 2 and x = 9 Therefore, A = 2 and B = 9. At (-Inf , 2] : decreasing (...
*October 29, 2013*

**chemistry**

The reaction is P4 + O2 -> P2O5 Balancing, P4 + 5 O2 -> 2 P2O5
*October 29, 2013*

**Physics**

*lol sorry, in the last calculation that should be 5.125 * 10^-11 * 6.022 * 10^23 but the answer is still the same. :)
*October 29, 2013*

**Physics**

Since the gas is ideal, we can use the Ideal Gas Law: PV = nRT where P = pressure in atm V = volume in L n = number of moles of air R = universal gas constant = 0.0821 L-atm/mol-K T = temperature in K We first convert the given in the appropriate units: V = 19.4 cm^3 cm^3 is ...
*October 29, 2013*

**Ap chemistry**

We first write the balanced chemical reaction: 4 Mn + 3 O2 -> 2 Mn2O3 ; ΔH = -962.3 kJ/mol Mn2O3 We then get the number of moles Mn by dividing the given mass by molar mass of Mn. The molar mass of Mn is 54.94 g/mol (get a periodic table and search for it). 6.4 / 54.94...
*October 29, 2013*

**algebra**

You forgot to type the function...
*October 29, 2013*

**Gen Chem 2**

f (# of equivalents) is equal to number of ionizable H+ (in acid-base titration), though it has also other meaning, for instance, in electrochemistry. Here, f = 2 because H2SO3 has 2 H+.
*October 29, 2013*

**GCC**

In the activity series, Na is more reactive than Mg, thus it can displace Mg: Mg(NO3)2 + Na -> NaNO3 + Mg Balancing the reaction, Mg(NO3)2 + 2Na -> 2NaNO3 + Mg Hope this helps :)
*October 29, 2013*

**Maths**

Your solution and answer are actually both correct. :)
*October 28, 2013*

**chemistry**

lol I think you forgot to put the arrow symbol somewhere in those reactions. But it can still be answered. The answer is Ba(NO3)2(aq) + Na2CrO4(aq) -> BaCrO4(s) + 2NaNO3(aq) This is just a double displacement reaction. And looking at the charge of each element involved (in ...
*October 27, 2013*

**Math**

No, you don't have to. 30 / 3 = 10 Here, 10 is positive because both 30 and 3 are positive. 30 / -3 = -10 While here, one of them is negative so the answer must also be negative. *Note that if however, both 30 and 3 are negative, the answer is positive.
*October 27, 2013*

**Math**

Your solution and answer are actually correct. :) Let's do the checking part: Y = 4Y + 30 if Y = -10, -10 = -10(4) + 30 -10 = -40 + 30 -10 = -10 Since both sides of the equation are equal, then Y is indeed equal to -10. Hope this helps :3
*October 27, 2013*