# PHYSICS

posted by .

Grains of fine California beach sand are approximately spheres with an average radius of 50 μm and are made of silicon dioxide, which has a density of 2.4 × 103 kg/m3. What mass of sand grains would have a total surface area (the total area of all the individual spheres) equal to the surface area of a cube 1.1 m on an edge?

• PHYSICS -

The area of that cube would be 1.1^3 = 1.331 m^3.
If that is the total surface area of sand grains with radius 50*10^-6 m, the number N of sand grains would be given by
N*4*pi*(50^10^-6)^2 = 1.331
N = 4.23*10^7 grains

Each sand grain has a mass m given by
(4/3)*pi*(50*10^-6)^3*2400 = 1.273^10^-10 kg/grain

The mass of the N sand grains with an area of 1.331 m^3 is
5.4*10^-3 kg = 5.4 grams

Check my thinking and calculations.

• PHYSICS -

66

## Similar Questions

1. ### physics

Grains of fine California beach sand are approximately spheres with an average radius of 50 and are made of silicon dioxide. A solid cube of silicon dioxide with a volume of 1.00 m has a mass of 2600 kg. What mass of sand grains would …
2. ### Chemistry

In an experiment to find the percentage of calcium carbonate in sand from a beach, 1.86 g of sand reacted with an excess of dilute hydrochloric acid to give 0.55 g of carbon dioxide. CaCO3 (s) + 2HCL (aq) – CaCl2(aq) + CO2(g) + H2O …

What type of sand/rock is Malibu Beach made of and where did that sand originate?
4. ### Physics

The U.S army's parachuting team, the Golden Knights, are on a routine jumping mission over a deserted beach. On a jump, a 65 kg Knight lands on the beach with a speed of 4.0 m/s, making a .20 m deep indentation in the sand. With what …
5. ### physics

water at 20°C has viscosity n=1.0*10^-3 Ns/m^2. sand grains have density 2400kg/m^3. suppose a 1.1 mm diameter sand grain is dropped into a 51m deep lake whose water is a constant 20°C. If the sand grain reaches terminal speed almost …
6. ### chemistry

Silicon carbide is one of the hardest materials known. It is often known commercially as carborundum. Silicon carbide is used primarily as an abrasive for sandpaper and is manufactured by heating common sand (silicon dioxide, SiO2) …
7. ### Physics

Grains of fine California beach sand are approximately spheres with an average radius of 50 μm and are made of silicon dioxide, which has a density of 2.4 × 10^3 kg/m3. What mass of sand grains would have a total surface area …
8. ### Physics

Grains of fine California beach sand are approximately spheres with an average radius of 50 μm and are made of silicon dioxide, which has a density of 2.4 × 103 kg/m3. What mass of sand grains would have a total surface area …
9. ### child care

According to the CFOC guidelines, which of the following is true as it relates to grains?
10. ### Chemistry

Silicon carbide (SiC) is made by reacting sand (Silicon dioxide, SiO2) with powdered carbon at high temperature. Carbon monoxide is also formed. What is the percent yield if 51.4kg of SiC is recovered from processing 100.0kg of sand?

More Similar Questions