Answer:
0.004012km
Explanation:
Problem:
Conversion of millimeters(mm) to Kilometers:
value given = 4012mm
Here, we are converting from a submultiple unit to a multiple unit.
Millimeter depicts 10⁻³m and kilometer stands for 10³m
Now, we must find how many exponents will take us from 10⁻³ to 10³
careful examination shows that if we multiply a power of 10⁶ to 10⁻³ it will give a 10³:
i.e 10⁻³ x 10⁶ = 10⁻³⁺⁶ = 10³
Therefore,
10⁶mm = 1km
4,012mm = 
= 0.004012km
Answer:
The system gains 126100 J
Explanation:
The heat can be calculated by the equation:
Q = nxCxΔT, where Q is the heat, C is the heat capacity,n is the number of moles and ΔT is the variation of temperature (final - initial). The number of moles is the mass divided by the molar mass, so:
n = 250/4 = 62.5 mol.
The system must be in thermal equilibrium with the surroundings, so if the temperature of the surroundings decreased 97 K, the temperature of the system increased by 97 K, so ΔT = 97 K
Q = 62.5x20.8x97
Q = 126100 J
Answer:
2,760 grams NaCl
Explanation:
To find grams of NaCl, you need to (1) convert moles of Na to moles of NaCl (via mole-to-mole ratio from reaction) and (2) convert moles of NaCl to grams (via molar mass from periodic table). The final answer should have 3 significant figures based on the given measurement.
2 Na + Cl₂ --> 2 NaCl
Molar Mass (NaCl) = 22.99 g/mol + 35.45 g/mol
Molar Mass (NaCl) = 58.44 g/mol
47.2 moles Na 2 moles NaCl 58.44 grams
---------------------- x --------------------------- x ------------------------- =
2 moles Na 1 mole NaCl
= 2,758.368 grams NaCl
= 2,760 grams NaCl
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.
TMS has 12 protons which are all equivalent and four carbons, which are also all equivalent. This means that it gives a single, strong signal in the spectrum, which turns out to be outside the range of most other signals, especially from organic compounds.
