True or false a substance that undergoes a physical change is a different substance with different properties after the change.

If the pH of a wine is too high, say, 4.0 or above, the wine becomes unstable and has a flat taste. (a) A certain California red wine has a pH of 3.5, and a certain Italian white wine has a pH of 2.9.

A hydrogen atom has one proton, two neutrons, and no electrons. Is this atom an ion? Explain your answer.

Fossil originally has 254 g of carbon-14 but currently has 127 g of carbon-14 the fossil is most likely A 17,190 years old B 22,920 years old C 5730 years old D 11,460 years old

Which sample is a homogeneous mixture? A) NaCI (s) B) NaCl (aq) C) NaCl (g) D) NaCl (ℓ)

Choose the correct word from the drop-down menu to complete each sentence. vis dark, highly decomposed organic matter found in soil. vis a mixture of materials that holds moisture and drains well.

The activation energy for the reaction no2 (g) + co (g) ⟶no (g) + co2 (g) is ea = 100 kj/mol and the change in enthalpy for the reaction is δh = - 375 kj/mol.

What process transform solar energy into chemical energy?

When the reaction was carried out the calculated theoretical yield for water was 176 grams but the measured yield was 148 grams what is the percent yield

For an atom's electrons, how many energy sublevels are present in the principal energy level n = 4?

Attempt 2 A sample of gas contains 49.16 % N 2 gas, 19.85 % Br 2 gas, 9.95 % CO 2 gas, and 21.04 % of an unknown gas. The average atomic mass of the gas mixture is 50.71 u. Calculate the atomic mass of the unknown gas.