15 points!
Two students are comparing scientific experiments to investigations. They came up with the following ideas.

Student A: Testing plant growth in different types of soils
Student B: Comparing the water level in a lake during different times of the year

Which student gave an example of a scientific experiment?

Student A because it requires experimental and control groups
Student B because it requires a hypothesis
Student A because it is preferably done in natural settings
Student B because it is preferably done across a long period of time
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this doesnt have to be answered now, but I'd like it to be as soon as possible!

Abeaker with 2.00×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 4.70 ml of a 0.360 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.

Ascientist measures the speed of sound in a monatomic gas to be 449 m/s at 20∘c. what is the molar mass of this gas?

Imagine if during the cathode ray experiment, the size of the particles of the ray was the same as the size of the atom forming the cathode. which other model or scientific observation would have also been supported? 1. this would support dalton's postulates that proposed the atoms are indivisible because no small particles are involved. 2. this would support bohr's prediction about electrons moving in orbits having specific energy. 3. this would support bohr's prediction about electrons being randomly scattered around the nucleus in the atom. 4. this would support dalton's postulates that proposed that atoms combine in fixed whole number ratios to form compounds.