Who developed the polio vaccine?

George Marshall

Jonas Salk

Marie Curie

Carlos Finlay

Which factors affect electronegativity? A. Atomic radius and number of unshielded protons B. Density of the element and atomic radius C. Number of electrons and atomic radius D. Number of unshielded electrons and density of the element

Is boiling water a chemical reaction?

Write 40% as a fraction in simplest form.

What is the density of sand if the volume is 40.0 ml and the mass is 62.3 g?

Is methane (CH4) a covalent or ionic bond? Give reasons and explain why is it so.

How much heat is needed to raise the temperature of 75 g of a substance by 15 C when the specific heat is 0.92 J/g-C?

A nitric acid solution flows at a constant rate of 5L/min into a large tank that initially held 200L of a 0.5% nitric acid solution. The solution inside the tank is kept well stirred and flows out of the tank at a rate of 10L/min.

How many molecules are in 237g (about a cup of water)

3. A compound was analyzed and found to contain 9.8 g of nitrogen, 0.70 g of hydrogen, and 33.6 g of oxygen. What is the empirical formula of the compound?

A 126-gram sample of titanium metal is heated from 20.0°C to 45.4°C while absorbing 1.68 kJ of heat. What is the specific heat of titanium?