Please help me with these Chemistry questions.

Question

When an atom emits a beta particle...

a. the mass number decreases by 4 amu.

b. the mass number decreases by 1 amu.

c. the atomic number increases by 1 amu

d. the atomic number decreases by 2 amu

How would you describe a solution that contains 100 grams of sodium nitrate in 100 g of water at 35°C? Use the graph below.

a. saturated

b. unsaturated

c. supersaturated

d. cannot be determined with this graph

Which line angle-formula represents an alkane? 1,2,3, or 4.

The hydroxide ion concentration of a solution is 3.8 x 10⁻³. What is the pH? Show your work to earn credit.

Answer 1

For question 1) a beta particle is an electron (-1 charge) emitted from the nucleus by a neutron:

n = p + beta hence you have increased the number of protons by 1 and, hence, the atomic number increase by 1

For question 2) Notice, on the graphm that the 100g of NaNO3 on the vertical (ordinate) intersects with the temp between 30-40 on the horizontal (abscissa) - so it appears that a 100g of NaNO3 dissolved in 100g of water results in a saturated solution at approximately 35 C

for questioin 3) - alkanes can only have single bonds hence the third drawing is the correct line representation of an alkane - alkenes etc - have a double bond

for question 4)

pH = -log 3.8 x 10-3 = -log 3.8 - log 10-3 = -0.58 + 3 = 2.42