Answer:
3.01 x 10²¹
Explanation:
Molar mass of h₂o =18.01528 g/mol.
it means 1 mole h₂o=18.01528 g .....(1)
1 mole = 6.022 × 10^23 molecules
so,
1 mole h₂o =6.022 × 10^23 molecules=18.01528 g [from 01]
now,
18.01528 g h₂o has= 6.022 × 10^23 molecules
9.00x10⁻² g h₂o has= ( 6.022 × 10^23 x 9.00x10⁻² ) /18.01528 molecules
=3.008 x 10²¹ molecules
≈ 3.01 x 10²¹ molecules
Answer:
I think so
Explanation:
There are atone in every particle so the more particles, the more atoms
Answer:
A. A physical change took place during this experiment
Explanation:
A physical change is one of the changes that occurs in a reaction. It is a kind of change characterized by no change to the chemical composition of the substances involved. It involves reactions such as melting, change of state, freezing, boiling etc.
According to this question, Lydia added 50 grams of sugar to 200 milliliters of water, then, stirred the mixture, until the sugar eventually dissolved into the water and couldn’t be seen. This change involved no change in color, odor, or temperature. Hence, Lydia's experiment represents a PHYSICAL CHANGE because only DISSOLUTION occured.
In an experiment, Lydia added 50 grams of sugar to 200 milliliters of water. She stirred the mixture, and the sugar eventually dissolved into the water and couldn’t be seen. The volume of the solution increased, but there was no noticeable change in color, odor, or temperature. Which statement best describes what happened in Lydia’s experiment? A. A physical change took place during this experiment. B. A chemical change took place during this experiment. C. A compound was formed during this experiment. D. A heterogeneous mixture was
A chemical formula can tell one the consisting atoms, the types of atoms and which they belong.Also through mole ratios, the number of atoms contained in a compound can also be identified through the chemical formula. In this problem, the answer is a. True.
Answer:
-1815.4 kJ/mol
Explanation:
Starting with standard enthalpies of formation you can calculate the standard enthalpy for the reaction doing this simple calculation:
∑ n *ΔH formation (products) - ∑ n *ΔH formation (reagents)
This is possible because enthalpy is state function meaning it only deppends on the initial and final state of the system (That's why is also possible to "mix" reactions with Hess Law to determine the enthalpy of a new reaction). Also the enthalpy of formation is the heat required to form the compound from pure elements, then products are just atoms of reagents organized in a different form.
In this case:
ΔH rxn = [(2 * -1675.7) - (3 * -520.0)] kJ/mol = -1815.4 kJ/mol
