Answer:
The reaction D has the value of ΔH°rxn equal to ΔH°f for the product.
Explanation:
The ΔH°f for product is equal to ΔH°rxn when the reagents are in their elemental state (ΔH°f = 0) and form one mole of product.
We have to find the reagents that are in their elemental state and that only form one mole of product:
A) 2Ca (s) + O₂ (g) → 2CaO (s)
The reagents are in their elemental state but the reaction forms two mole of product.
B) C₂H₂ (g) + H₂ (g) → C₂H₄ (g)
C₂H₂ (g) is not in its elemental state.
C) 2C (graphite) + O₂ (g) → 2CO (g)
Graphite and Oxygen are in their elemental state but the reaction forms two mole of product.
D) 3Mg (s) + N₂ (g) → Mg₃N₂ (s)
Magnesium and Nytrogen are in their elemental state and the reaction forms one mole of product.
E) C (diamond) + O₂ (g) → CO₂ (g)
Diamond is not in its elemental state.
Explanation:
The density of a substance can be found by using the formula

From the question
mass of block = 5 g
volume = 15 mL
The density of the block is

We have the final answer as
<h3>0.33 g/mL</h3>
The block will float on water since it's density is less than that of water which is 1 g/mL
Hope this helps you
Answer:
Its pressure will be 0.54 atm at 100 K.
Explanation:
Gay-Lussac's law indicates that, as long as the volume of the container containing the gas is constant, as the temperature increases, the gas molecules move faster. Then the number of collisions with the walls increases, that is, the pressure increases. That is, the pressure of the gas is directly proportional to its temperature.
Gay-Lussac's law can be expressed mathematically as the quotient between pressure and temperature equal to a constant:

Studying two different states, an initial state 1 and a final state 2, it is satisfied:

In this case:
- P1= 1.75 atm
- T1= 50 °C= 323 K (being 0 C=273 K)
- P2= ?
- T2= 100 K
Replacing:

Solving:

P2= 0.54 atm
<u><em>Its pressure will be 0.54 atm at 100 K.</em></u>
Answer: Don't know sorry
Explanation: And I-oop SkSk
Answer:
A covalent bond
Explanation:
the atoms bond by sharing electrons. Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom.