How many neutrons does an element have if its atomic number is 40 and its mass number is 154

A sample of neon gas at 1.20 atm compresses from 0.250 l to 0.125 l. if the temperature remains constant, what is the final pressure

Soils are made up of a mineral portion, an organic portion, air and water. What is meant by the word organic?

Which compound is part of the structure of another compound listed? A. amino acids B. nucleic acids C. proteins

Propane burns in air to produce Carbon dioxide and water. What is this type of chemical reaction called?

A model of the solar system with the Sun at the center is said to be heliocentric. true or false

El cuerpo humano tiene unos 6 billones de células (6,0x1012) y la población de la Tierra es de unos 8 000 millones de personas. Con estos datos aproximados, calcula las moles de células humanas que hay en la Tierra.

True or false: an apple looks red because it absorbs red light?

Polar molecules have a partial positive charge on one side and a partial negative charge on the other side, a separation of charge called a dipole. Which of the following molecules has this kind of a dipole? a. IonicB. Covalent

A fictitious element X is composed of 15.0% of the isotope X-51, 15.0% of the isotope X-52, and 70.0% of the isotope X-53. Estimate the atomic mass of element C

Which substance is the limiting reactant when 4.0 g of sulfur reacts with 6.0 g of oxygen and 8.0 g of sodium hydroxide according to the following chemical equation: 2 S (s) + 3 O2 (g) + 4 NaOH (aq) → 2 Na2SO4 (aq) + 2 H2O (l) A. O2 (g) B. S (s) C.