Which of these reactions are redox reactions? Check all that apply.

Cd + HCl → CdCl2 + H2

CuCl2 + Na2S → 2NaCl + CuS

CaCO3 → CaO + CO2

2ZnS + 3O2 → 2ZnO + 2SO2

CH4 + 2O2 → CO2 + 2H2O

Which statement is true? a. Speed is a scalar quantity and velocity is a vector quantity. b. Speed and velocity are both scalar quantities. c. Speed and velocity are both vector quantities. d.

Which bear describes a chain reaction associated with nuclear reaction

A river current has a velocity of 10 km/h related to the shore and a boat moves in the same direction as a current of 10 km/h related to the River how can the velocity of the boat related to the shore fee calculated

1. Which weather instrument is used to measure air temperatures recorded on a weather map? (1) anemometer (3) thermometer (2) wind vane (4) barometer

Which sentences describe disadvantages of burning fossil fuels instead of using hydrogen fuel cells? Burning fossil fuels contributes to climate change. Burning fossil fuels takes place inside expensive fuel cells.

Which of the following bonds is the most polar in nature: (1) Cl2 (2) HCl (3) HBr (4) HI

Combustion analysis of a 13.42-g sample of the unknown organic compound (which contains only carbon, hydrogen, and oxygen) produced 36.86g CO2 and 10.06g H2O. The molar mass of estriol is 288.38g/mol.

What concept in Dalton's atomic theory has been modified? A. All matter is composed of atoms. B. Atoms of different elements have different properties and masses. C. Atoms can combine in chemical reactions. D. Atoms cannot be divided.

Which particles in an atom can increase or decrease in number without changing the identify of the elements?

Which process best describes the cause of lightning