All categories

3 years ago

How many joules of heat are required to heat 125 g aluminum from 19.0°C to 95.5°C?

Chemistry

2 answers:

bekas [8.4K]3 years ago

7 0

Answer: The amount of heat required is 8625.4 J

Explanation:

To calculate the heat required, we use the equation:

$q=mc\Delta T$

where,

q = heat required = ?

m = mass of aluminium = 125 g

c = specific heat capacity of aluminium = 0.902 J/g.°C

$\Delta T$ = change in temperature = $T_2-T_1=95.5-19=76.5^oC$

Putting values in above equation, we get:

$q=125g\times 0.902J/g.^oC\times 76.5^oC\\\\\q=8625.4J$

Hence, the amount of heat required is 8625.4 J

Katen [24]3 years ago

3 0

The specific heat of aluminum is 0.902 J/gC. E=m*cp*delta T, or
125*0.902*(95.5-19)= 8630 J

You might be interested in

when using a clamp and ring stand to hold glassware and tools, what is the best position for the clamp?

lora16 [44]

The bottom

Explanation:

4 0

2 years ago

Consider the reaction. PCl5(g)↽−−⇀PCl3(g)+Cl2(g) K=0.042 The concentrations of the products at equilibrium are [PCl3]=0.18 M and

tatyana61 [14]

Answer: The equilibrium concentration of $PCl_5$ is 1.285 M.

Explanation:

The chemical equation for the decomposition of phosphorus pentachloride follows:

$PCl_5(g)\rightleftharpoons PCl_3(g)+Cl_2(g)$

The expression for equilibrium constant is given as:

$K_c=\frac{[PCl_3][Cl_2]}{[PCl_5]}$

We are given:

$K_c=0.042$

$[PCl_3]=0.18M$

$[Cl_2]=0.30M$

The concentration of solid substances are taken to be 1. Thus, they do not appear in the equilibrium constant expression.

Putting values in above equation, we get:

$0.042=\frac{0.18\times 0.30}{[PCl_5]}$

$[PCl_5]=1.285$

Hence, the equilibrium concentration of $PCl_5$ is 1.285 M.

6 0

2 years ago

Where does an eagle get the energy it needs to grow and to fly?

NeTakaya

An eagle gets energy from food. When the eagle eats food it gives them energy to be active just like us humans

7 0

2 years ago

Read 2 more answers

Which of the following statement is FALSE? a. Lowering the free energy of the transition state can increase a reaction rate. b.

ryzh [129]

Answer: Option (c) is the correct answer.

Explanation:

Activation energy or free energy of a transition state is defined as the minimum amount of energy required to by reactant molecules to undergo a chemical reaction.

So, when activation energy is decreased then molecules with lesser amount of energy can also participate in the reaction. This leads to an increase in rate of reaction.

Also, increase in temperature will help in increasing the rate of reaction.

Whereas at a given temperature, every molecule will have different energy because every molecule travels at different speed.

Hence, we can conclude that out of the given options false statement is that at a given temperature and time all molecules in a solution or a sample will have the same energy.

8 0

3 years ago

The following is a list of weak acids and their Ka values.HOCl hypochlorous acid 3.5 x 10^-8H2S hydrogen sulfide 1.1 x 10^-7HCN

notsponge [240]

Answer:

(a) HNO₂ nitrous acid 4.5 x 10^-4 is strong acid

(b) Ka expression $Ka = \frac{[H^{+}][NO_{2} ^{-}] }{[HNO_{2}] }$

(c) List of Conjugate Bases

OCl⁻, S²⁻, CN⁻, NO₂⁻

(d) cyanide ion is strongest conjugate base.

(e) pH and pOH of Hypochlorous acid = 4.22 & 9.77

pH and pOH of hydrogen sulfide = 4 & 10

pH and pOH of hydrocyanic acid = 5.2 & 8.79

pH and pOH of nitrous acid = 2.17 & 11.8

Explanation:

(a) Ka and acidity are directly proportional to each other

hence nitrous acid is the strongest acid since it has highest Ka value.

(b) Ka expression of nitrous acid

HNO₂ → H⁺ + NO₂⁻

⇒ $Ka = \frac{[H^{+}][NO_{2} ^{-}] }{[HNO_{2}] }$

H₂S hydrogen sulfide = S²⁻(sulphide ion)

HCN hydrocyanic acid = CN⁻(cyanide ion)

HNO₂ nitrous acid = NO₂⁻(nitrite ion)

(d) We know according to Bronsted acid base concept Weak acid have strongest conjugate base

according to this hydrocyanic acid is weak acid so the corresponding conjugate base i.e. cyanide ion is strongest conjugate base.

5 0

3 years ago