Final answer:
Option (a) with 8g of sodium bicarbonate in 160g of water has the lowest mass by mass percentage of 4.76%.
Step-by-step explanation:
In order to find the lowest mass by mass percentage, we need to calculate the mass of sodium bicarbonate in each solution and divide it by the total mass of the solution. Let's calculate the mass by mass percentage for each option:
(a) 8g of sodium bicarbonate in 160 g of water: (8g / 168g) x 100% = 4.76%
(b) 16g of sodium bicarbonate in 200 g of water: (16g / 216g) x 100% = 7.41%
(c) 12g of sodium bicarbonate in 180 g of water: (12g / 192g) x 100% = 6.25%
(d) 10g of sodium bicarbonate in 170 g of water: (10g / 180g) x 100% = 5.56%
Therefore, option (a) with 4.76% mass by mass percentage has the lowest mass by mass percentage.