Rust on a nail is a chemical change.
Ice melting IS a physical change. Ice is made of water, when you melt ice its still water. Just in a different physical state.
Answer:
9.89 x 10²³ molecules H₂S
Explanation:
To find the molecules of H₂S, you need to (1) convert grams S to moles S (via the atomic mass of sulfur), then (2) convert moles S to moles H₂S (via the mole-to-mole ratio from equation coefficients), and then (3) convert moles H₂S to molecules H₂S (via Avogadro's Number). It is important to arrange the ratios/conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value.
Atomic Mass (S): 32.065 g/mol
2 H₂S(s) + SO₂(g) -----> 3 S(s) + 2 H₂O(l)
Avogadro's Number:
6.022 x 10²³ molecules = 1 mole
79.0 g S 1 mole 2 moles H₂S 6.022 x 10²³ molecules
--------------- x --------------- x ---------------------- x ------------------------------------- =
32.065 g 3 moles S 1 mole
= 9.89 x 10²³ molecules H₂S
Answer:
SUBSTANCES
Explanation:
According to this question, Jasmine is conducting an experiment in order to see how much temperature change occurs when three different substances are heated. Based on this experiment, the INDEPENDENT VARIABLE, which is the variable that is changed or manipulated is SUBSTANCES.
A controlled experiment is an experiment where all other variables except the INDEPENDENT VARIABLE is kept the same or unchanged. The independent variable is the only variable allowed to change, which in this case is the SUBSTANCES USED.
Answer:
The volume is 406 mL
Explanation:
Step 1: Data given
Molarity of a zinc nitrate solution = 1.3 M
Mass of zinc nitrate = 100 grams
Molar mass of Zn(NO3)2 = 189.36 g/mol
Step 2: Calculate moles Zn(NO3)2
Moles Zn(NO3)2 = mass Zn(NO3)2 / molar mass Zn(NO3)2
Moles Zn(NO3)2 = 100.0 grams / 189.36 g/mol
Moles Zn(NO3)2 = 0.5281 moles
Step 3: Calculate volume
Molarity = moles / volume
Volume = moles / molarity
Volume = 0.5281 moles / 1.3 M
Volume = 0.406 L = 406 mL
The volume is 406 mL