One of the signs of a chemical reaction is taking place

If a chemical reaction occurs in a direction that has a positive change in entropy thenGroup of answer choicesthe change in enthalpy must be negative. the reaction must be spontaneous. heat goes from the system into the surroundings.

Is crumpling a piece of paper chemical changes

What information is provides by the mass number A, which is the superscript in the atomic symbol?

The ratio of sizes between the ionic radii of anions and cations in a cell has no influence on the manner of packing for that cell. a. True b. False

A sample of phosphorus-32 has a half-life of 14.28 days. If 55 g of this radioisotope remain unchanged after approximately 57 days, what was the mass of the original sample?

How many moles are in 12.5 g of H2O

How do the atomic number and the number of protons relate to one another? The atomic number tells us the number of protons The atomic number is protons + neutrons They do not Electron Cloud

Check my work? 150 g of an unknown liquid is heated with 24,975 kJ of heat to form 0°C to 75°C. Identify the unknown liquid. Substance C (J/g-°C) Water (ice) 2.05 Ammonia (liquid) 4.70 Ethanol 2.44 Gasoline 2.22 Water (liquid) 4.18 Water (vapour) 2.

The distance from the sun to the earth is 1.496x10^8 km. How long does it take light to travel from the sun to the earth

10. Airbags in automobiles contain the compound sodium azide, NaN3. A crash triggers the decomposition reaction of NaN3 to produce nitrogen gas, which causes the airbag to inflate. How many grams of NaN3 are required to produce 90.