Why does a person's heart rate increase during exercise?

(1) Less oxygen is needed.

(2) More oxygen is needed.

(3) Less carbon dioxide is needed.

(4) More carbon dioxide is needed

What type of energy transfer takes place when turning on a burner on the stove

Which state of matter has a definite volume and takes the shape of its containter

What is the mol:mol ratio of nonane to carbon dioxide

A 3.87mg sample of an organic compound gave 5.80mg CO² and 1.58mg h²O on combustion. Deduce the empirical formula of the compound.

How many grams are 1.20x10^24 atoms of potassium.

Which of the following represents a chemical change? Bending a wire Freezing of water Fireworks exploding Melting of a wax candle

5.00 L of a gas is collected at 100K and then allowed to expand to 20.0 L. What must the new temperature be in order to maintain the same pressure? A. 400 °C B. 127 °C C. 223 °C D. 627°C

Before the initial explosion was the matter hot or cold

Which of the following atoms has seven valence electrons? chlorine (Cl) nitrogen (N) manganese (Mn) oxygen (O)

A.) During an experiment, a student adds 2.90 g of CaO to 400.0 mL of 1.500 M HCl. The student observes a temperature increase of 6.00 °C. Assuming the solution/'s final volume is 400.0 mL, the density if 1.00 g/mL, and the heat capacity is 4.