Please balance the equation: Co(H20)6²+ + 4Cl^- <=> CoCl4²- + 6H2O

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.

Which statement describes the phase change that occurs when dry ice is placed in an open container at room temperature?

Answer asap need by wednesday morning calculate the ph of 0.16m ch3cooh which has ka = 1.74 x 10-5 mol dm-3 best answer will be brainliest