How do you know when an element is a noble gas

What is the concentration of sodium phosphate contains 0.60 M Na+? I'm not sure what to do and how to figure how to do this question.

Where did the noble gases get their name

Why burning methane does not produce acid rain

If 6 liters of hydrogen gas are used, how many liters of nitrogen gas will be needed for the above reaction at stp?

How many kmin (kilominutes) are there in 44 weeks and 5 days? Report the answer to 4 significant figures.

Convert 3.57 moles of aluminum to grams

An average microwave uses a frequency of 2.54 GHz. How much energy is emitted?

Why scientist form a hypothesis

Step two of the procedure states: "Using sterile technique, place a loopful of inoculum from the M. luteus culture in the drop of nigrosin and mix." Which of the procedures qualifies as sterile technique?

If 4.34 moles of potassium react with excess water, how many moles of hydrogen gas would be produced at STP