A helium balloon contains 0.48 g of helium. Given the molecular weight of helium is 4.0g/mol, how many moles of helium does it contain?

Which outcome can be expected from adding a catalyst to a chemical reaction? A. The reaction will speed up B. Chemical equilibrium will not be reached C. The reaction will slow D. No change will occur

In a DNA sample, 15% of the bases are thymine (T). What percentage of the bases in this sample are cytosine (C) ? A. 15% B. 30% C. 35% D. 85%

Energy is defined as the A ability to cause change in matter or the capacity to do work B amount of matter in a substance c feree times distance- D distance divided by the time

What is the volume occupied by 3.00 * 1023 molecules of bromine gas at STP? a 404.5 L B. 0.80 L C. 2.2 * 10-2 D. 11.2 L

Rachel carson's warning in silent spring was focused on

How do carbohydrates relate to organic chemistry

Periodic table, chemistry questions who discovered lanthanides. how did they discover it, when did they discover it.

A flask containing 155cm^3 of hydrogen was collected under a pressure of 22.5kPa. What pressure would have been required in order for the volume of the gas to have been 90.0 cm^3 at constant temperature?

Which change is most likely to occur when a molecule of H2 and a molecule of I2 collide with proper orientation and sufficient energy? 1. a chemical change, because a compound is formed 2. a chemical change, because an element is formed 3.

Which substance is a diatomic molecule? a. he b. o2 c. co2 d. h2o?