Which quantities must be conserved in all chemical reactions?

1) mass, charge, density

2) mass, charge, energy

3) charge, volume, density

4) charge, volume, energy

Which of these elements has physical and chemical properties most similar to silicon (Si) ?

This is how krypton appears in the periodic table. A purple box has K r at the center and 36 above. Below it says krypton and below that 83.80. Rounded to the nearest whole number, how many protons are in an atom of krypton? 36 48 84 120

In a laboratory activity, the density of a sample of vanadium is determined to be 6.9 g/cm3 at room temperature. What is the percent error for the determined value? * 0.15% 0.87% 13% 15%

i have a question about atoms. How would i find electrons when the atomic number is the number of protons and electrons?

How much faster will neon effuse than krypton, given that the molar mass of krypton is 83.8 grams and that of neon is 20.18 grams?

At the same pressure, about 25 times more co2 will dissolve in plasma as o2. why does this occur?

Describe what occurs when a gas is collected by water displacement, including why a table of water vapor pressure values is needed.

The theory of plate tectonics

A sample of sodium reacts completely with 0.568 kg of chlorine, forming 936 g of sodium chloride. What mass of sodium reacted?

When do water molecule forms hydrogen bond with another water molecule which atoms are involved in the interation?