39 is two fifths of what number

An atom with an atomic number of 12 and a mass number of 25 can best be described by which of these

Explain what causes air pressure:

Change of state may occur when?

If a glass bottle breaks into thousands of tiny pieces, what type of change occurs? A. physical only B. chemical only C. physical and chemical

When we say an object is hot, we are describing its velocity thermal energy wavelength chemical energy?

How many of the following elements have 2 unpaired electrons in the ground state? C Te Hf Si A) 1. B) 2. C) 3. D) 4.

Which has a higher frequency, a neutron or electron? Why?

1) Identify the intensive properties of a sample of matter: A. mass B. hardness C. color D. volume E. reflectivity

Suppose you have a buffer containing 0.400 M hydrazine and 0.300 M hydrazinium chloride at equilibrium. Then you add 25.2 g of NaOH to 2.0 L of the buffer. What change in pH is caused by the addition of the base? A) 0.99 B) 0.40 C) 8.71 D) - 0.36

The heart is an example of which level of organization within an organism? O cell organ tissue organ system O O