A number placed in front of an element symbol

Which method do you consider most appropriate for determining half-life?

Insulation is the percentage of energy that is actually used to perform work true or false

Why are frogs produce a huge amount of eggs?

Acetylene gas (C2H2) used in welding, pro - duces an extremely hot flame when it burns in pure oxygen according to the reaction 2 C2H2 (g) + 5 O2 (g) - → 4 CO2 (g) + 2 H2O (g). How much CO2 is produced when 20000 g of C2H2 burns completely?

Enough water is added to 10.5 grams of NaOH to produce 200 mL of solution. What is the mass/volume percent of the solution? A) 0.516% (m/V) B) 10.5% (m/V) C) 1.25% (m/V) D) 2.75% (m/V) E) 5.25 % (m/V)

Which of the following will most likely happen if you apply unbalanced forces to an object? It will change position. It will become charged. It will change mass. It will change size.

Magnetism easily separates what mixture? A). Sand and glass B). Sand and iron C). Sand and clay D). Sand and aluminum

Match the science with the best description?

Can magnetism be used to identify a substance

Nitrogen dioxide dimerizes to give dinitrogen tetroxide: 2NO2 (g) → N2O4 (g). At 298 K, 12.55 g of an NO2/N2O4 mixture exerts a pressure of 0.963 atm in a volume of 6.92 L. What are the mole fractions of the two gases in the mixture?