In which two types of reactions do opposite chemical changes occur?

a) double replacement and combustion

b) single replacement and double replacement

c) synthesis and decomposition

d) combustion and synthesis

the answer is = c) synthesis and decomposition

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.

An object of mass 10.0 kg and volume 1000 ml and density 10 g/ml sinks in water who’s density is 1.0 g/ml. what is the mass of the water which has been displaced in kilograms