Cement is a maxture of calcium and aluminium silicates, formed by heating limestom with clay.
4CaCO3(s) + Al, S1,0,(s) - 2CASIO (s) + Ca AlO3(s) + 4CO2(g)
clay
cement
A typical bag of cement has a mass of 25 kg. Calculate the mass of limestone (taken
calcium carbonate) required to make 25 kg of cement.
The moler mass of cement, taken as (2Casioz + C2 ALO). Is 446.6 gmor
IA: AL 27.0; C, 12.0; Ca, 40.1; 0, 16.0; SI, 28.1]
n(cement)=
n(CaCO3)=
Mr(CaCO3)=
mass(CaCO3)

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

Working with si (metric) units for each of the following commonly used measurements, indicate its symbol. liter gram milliliter kilogram meter centigram milligram centimeter kilometer second millimeter milliseconds

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.