C i think but you should pick it anyway
Answer:

Explanation:
1. Calculate the molar mass of Na₂SO₄

The molar mass of Na₂SO₄ is 142 g/mol.
2. Calculate the moles of Na₂SO₄

3. Calculate the mass of Na₂SO₄

Answer:
Newton's First Law of Motion
Explanation:
Newton’s first law of motion is when an object can’t move or change their speed without some type of force. Inertia is included since is caused by unbalanced force.
Answer : Hypothesis.
Explanation : Hypothesis is defined as the supposition or proposed explanation which can be made on the basis of limited available evidence as a starting point for further investigation. Here, in this question the proposed explanation for the changing colors of the sky is an example of a hypothesis.
A hypothesis has to be supported with scientific experiments which are reproducible by several experiments and test results have to be valid to be called as a scientific theory.
Answer:
a) acidic; [H+] = 10^-2.5 = 3 x 10^-3
b) basic; [H+] = 10^-11.7 = 2 x 10^-12
c) slightly acidic (almost neutral); [H+] = 10^-6.8 = 1.6 x 10^-7
d) acidic; [H+] = 10^-3.31 = 4.9 x 10^-4
Explanation:
pH < 7 is acidic; pH > 7 is basic; pH = 7 is neutral
[H+] = 10^-pH