How can you tell that a chemical change has occurred?

Describe a way that people might be able to solve each envioronmental problem listed below. coal mining can harm habitats and cause pollution.

Make a chart comparing protons, neutrons, and electrons. Include their mass, location, and electrical charge.

Which best describes a force? a vector with magnitude and direction a vector with speed and strength a vector with direction only a vector with strength only Mark this and retum Save and Exit Next Submit

Which of the following is an acid-base neutralization reaction? A. Sn+2HBr-->SnBr2+H2 B. HCL+KOH---> KCL+H2O C. 2AlCl3 + 3Ca (OH) 2--> 2Al (OH) 3 + 3CaCl2 D. 2C2H6+7O2-->4CO2 + 6H2O

Consider a process in which 100 kJ of energy is transferred reversibly and isothermally as heat to a large block of copper. Calculate the change in entropy of the block if the process takes place at (i) 0 °C, (ii) 50 °C.

How much heat is needed to raise the temperature of 75 g of a substance by 15 C when the specific heat is 0.92 J/g-C?

A nitric acid solution flows at a constant rate of 5L/min into a large tank that initially held 200L of a 0.5% nitric acid solution. The solution inside the tank is kept well stirred and flows out of the tank at a rate of 10L/min.

How many molecules are in 237g (about a cup of water)

3. A compound was analyzed and found to contain 9.8 g of nitrogen, 0.70 g of hydrogen, and 33.6 g of oxygen. What is the empirical formula of the compound?

A 126-gram sample of titanium metal is heated from 20.0°C to 45.4°C while absorbing 1.68 kJ of heat. What is the specific heat of titanium?