What is the answer helpnme plz

Alexandra [31]

Answer: I think that trains move faster then cars! Buttt, The trains are much stronger and bigger, then cars or trucks. Even if they move slowly they can still crush something smaller then them.

Explanation: ( didnt really understand the question, but i tried)

5 0

3 years ago

A student dissolves 15.0 g of ammonium chloride(NH4Cl) in 250. 0 g of water in a well-insulated open cup. She then observes the

iren2701 [21]

Answer:

1) Endothermic.

2) $Q_{rxn}=4435.04J$

3) $\Delta _rH=15.8kJ/mol$

Explanation:

Hello there!

1) In this case, for these calorimetry problems, we can realize that since the temperature decreases the reaction is endothermic because it is absorbing heat from the solution, that is why the temperature goes from 22.00 °C to 16.0°C.

2) Now, for the total heat released by the reaction, we first need to assume that all of it is released by the solution since it is possible to assume that the calorimeter is perfectly isolated. In such a way, it is also valid to assume that the specific heat of the solution is 4.184 J/(g°C) as it is mostly water, therefore, the heat released by the reaction is:

$Q_{rxn}=-(15.0g+250.0g)*4.184\frac{J}{g\°C}(16.0-20.0)\°C\\\\ Q_{rxn}=4435.04J$

3) Finally, since the enthalpy of reaction is calculated by dividing the heat released by the reaction over the moles of the solute, in this case NH4Cl, we proceed as follows:

$\Delta _rH=\frac{ Q_{rxn}}{n}\\\\\Delta _rH= \frac{ 4435.04J}{15.0g*\frac{1mol}{53.49g} } *\frac{1kJ}{1000J} \\\\\Delta _rH=15.8kJ/mol$

Best regards!

4 0

3 years ago

Which of the following statements statements expresses the following chemical equation with words?

nadezda [96]

Answer:What are the two half reactions that show how many electrons are gained or lost by each species in the reaction:

Ni2+(aq) + Mg(s) → Ni(s) + Mg2+(aq)?

atoms cannot be created or destroyed in a chemical reaction

7 0

3 years ago

When considering the relationship among standard free energy change, equilibrium constants, and standard cell potential, the equ

DedPeter [7]

Answer:

ΔG° = - RTLnK is used to find the standard cell potential given the equilibrium constant

Explanation:

for an ideal disolution:

⇒ ΔG = RT∑ni LnXi

∴ ΔG = ( μi - μi*)ni

∴ μ : chemical potential

∴ μ*: chem. potential of the pure component at T and P.

⇒ ΔG = μi - μi* = RT LnXi

for a equilibrium reaction:

⇒ ∑ νi*μi = 0

⇒ ΔGr = ΔG°+ RT Ln Kx = 0

⇒ ΔG° = - RT LnKx

4 0

4 years ago

How many moles of chromium are present in 13.7 grams of chromium metal? Give your answer to 3 decimal

Alex

7.834 i'm sorry if its wrong i might have done some wrong calculations

6 0

4 years ago