When was the day the coldest?​

If 1.63 times 10 negative 4 of helium dissolves in 100.0g of water, what is the concentration in parts per million

An object displaces 652 ml of water. the volume of the object is: 0.652 cm³ 6.52 cm³ 65.2 cm³ 652 cm³

An unknown solution has a ph of 7.2. which of these chemicals is likely to cause the greatest decrease in the ph of the solution when added to the solution? hf koh nh3 hno3