A gas can be produced when you boil water (steam). This isn't classified as a chemical change, though. This is because a new substance is not formed, the water just changes physical states from liquid to gas
Randomly pick 50 students from each grade level. 1:1 ratio of boys to girls. Randomly section 1/2 of the 50 students from each grade level into groups A and B. Have group A drink Starbucks. Have group B drink nothing. Hand the same academic test of mixed subjects to each student. Record the data.
Answer:
2.29 × 10⁻⁴ moles
Explanation:
Data Given:
Chemical Symbol of Zinc = Zn
Mass of Zinc = 1.5 × 10⁻² g
A.Mass of Zinc = 65.38 g.mol⁻¹
The Atomic Mass of Zinc can be obtained from periodic table. While, the mass is given in statement. Also, it is important to know the symbol because some elements exist in diatomic or polyatomic forms i.e. H₂, N₂, S₈ e.t.c.
Mole is the unit used to calculate the amount of substance. It has following general forms,
Mole = Mass / M.Mass
And,
Mole = # of Particles / 6.022 × 10²³ particles.mol⁻¹
Hence, using first equation,
Moles = 1.5 × 10⁻² g / 65.38 g.mol⁻¹
Moles = 2.29 × 10⁻⁴ moles
Answer:
77%
1.98/2.57= 0.770428016 = 77%
Answer:
A. 0.0233
Explanation:
according to the equation,
no. of moles of KBrO3 : no. of moles of Br2 = 1 : 3
no. of moles of KBrO3
= ⅓ × 0.0700mol
= 0.0233 (3 sig. fig.)