Match the grams of each element or compound to the corresponding number of moles of that element or compound.

1. 20.0g H 0.011 moles

2. 0.50 g Na 20.0 moles

3. 2.0 x 102 mg H2O 0.022 moles

Why are burning candles and rusting nails examples of chemical change?

The atomic number of an element best corresponds to which of the following? O The mass of an atom of that element. O The number of electrons orbiting the nucleus of an atom of that element.

What is between the cornea and iris

Is this statement true or false? Acids are corrosive. A. True B. False

The principle of conversion of mass is true a. only for reactions that take place in open systems b. only for reactions that take place in closed systems c. for reactions in both open and closed systems

Andrea is performing an experiment in which she needs to know when a strong acid is present. She is not sure which indicator to use, so she looks up the following table in her science textbook. Indicator pH range thymol Blue 1.2 - 2.8 phenol Red 6.

Which represents the balanced nuclear equation for the beta plus decay of C-11? Superscript 11 subscript 6 upper C right arrow superscript 11 subscript 5 upper B plus superscript 0 subscript plus 1 e.

Make a prediction for how to identify an unknown element and the chemical composition of a star

The density of HCN (hydrogen cyanide) gas at STP is 1.21g/L. What volume will 100.0g of HCN occupy at STP? A) 121 L B) 0.012 L C) 82.6 L D) none of the above

A 20.0 ml sample of 0.150 m ethylamine is titrated with 0.0981 m hcl. what is the ph after the addition of 5.0 ml of hcl? for ethylamine, pkb = 3.25