How do scientists know that the universe is expanding?

Which two particles in an atom are equal in number

Whitch of these is not a challenge an organism encounters

What would be the subscripts for the formula unit Ca_O_?

5. What is the density of an 84.7 g sample of an unknown substance if the sample occupies 49.6 cm3?

A balloon that had a volume of 3.50 L at 25.0°C is placed in a hot room at 40.0°C. If the pressure remains constant at 1.00 atm, what is the new volume of the balloon in the hot room? 2.19 L 3.33 L 3.68 L 5.60 L

The relationship between number of particles and pressure is As number of particles increases, pressure increases As number of particles increases, pressure decreases The two are not related

Consider the reaction: Al2S3 + 6 HCl → 2 AlCl3 + 3 H2S The reaction has a 29.1% yield. How many grams of Al2S3 are needed to react with 30.0 moles of HCl? a) The molar mass of Al2S3 is 150.16 grams/mole. b) The molar mass of HCl is 36.46 grams/mole.

Why is Earth's temperature just right for life? A. Earth's core is hot enough to heat Earth's surface. B. Earth's magnetic field creates suitable temperatures on Earth's surface. C. Earth's crust is warmed by heat from the sun. D.

Which of the following is an example of a chernical change? Boiling water Burning paper Dissolving sugar in water Melting gold

Part a by drawing molecular orbital diagrams for b2, c2, n2, o2, and f2, predict which of these homonuclear diatomic molecules are magnetic.