1. A Fertilizer contains 21% nitrogen by mass. What mass of this fertilizer, in kgs, is required for an application requiring 775 g of nitrogen?
2. Calculate the mass of a block of iron (p= 7.86 g/mL) with dimensions 52.8 cm x 6.74 cm x 3.73 cm.
3. The density of aluminum is 2.70 g/cm^(3). A square piece of aluminum foil, 9.0 inch on a side, is found to weigh 2.568 g. What is the thickness of this foil, in milliliters?
4. A recipe for roasting a cut of meat is 350*F. What is the temperature on the Celsius scale?
THANKS. 🙂
please show the complete solution. i’m not good at this so please help me. i want to learn how. thank you. 🙂
2 Answers

1. let mass of fertilizer be m
775= 21% of m
775 = 21/100 * m
3690 g = m
2. mass = density * volume
mass = 7.86 * 52.8 * 6.74 * 3.73 …………….. (since 1ml = 1 cm^3)
mass = 11872 ( approx) = 1.18 * 10^3 ( approx) ……………. (3 significant figure)
3. volume = mass/density
volume = 2.568 / 2.70
volume = 0.95 cm^3 ( approx)
1 inch = 3 cm
thus 9 inch = 27 cm
thus 27^2 * thickness = 0.95
thickness = 0.001 cm
4. (c*9/5) +32 = f
c = Celsius f = Fahrenheit
c = (f32) *5/9
c = (350 32) * 5/9
c = 318* 5/9
c = 176.66
: )

1)
0.21x = 775
x = 775/0.21
x = 3690.47 g
2)
52.8 cm x 6.74 cm x 3.73 cm = 1327.40256 cm^3
> 1 Cubic Centimeter = 1 Milliliter <
1327.40256 cm^3 = 1327.40256 mL
1327.40256 mL * 7.86 g/mL = 10433.38 g
Get the idea? You can do the other two.