Practice question 1 How many moles are in 5.64e25 atoms of iron (Fe)?

A 45-g aluminium spoon(specific heat 0.80 / J/gdegree Celsius) at 24 degree celsius is placed in 180 ml(180 grams) of coffee at

Vlad [161]

Explanation:

a) The amount of heat released by coffee will be absorbed by aluminium spoon.

Thus, $heat_{absorbed}=heat_{released}$

To calculate the amount of heat released or absorbed, we use the equation:

$Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})$

Also,

$m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)]$ ..........(1)

where,

q = heat absorbed or released

$m_1$ = mass of aluminium = 45 g

$m_2$ = mass of coffee = 180 g

$T_{final}$ = final temperature = ?

$T_1$ = temperature of aluminium = $24^oC$

$T_2$ = temperature of coffee = $85^oC$

$c_1$ = specific heat of aluminium = $0.80J/g^oC$

$c_2$ = specific heat of coffee= $4.186 J/g^oC$

Putting all the values in equation 1, we get:

$45 g\times 0.80J/g^oC\times (T_{final}-24^oC)=-[180 g\times 4.186J/g^oC\times (T_{final}-83^oC)]$

$T_{final}=80.30^oC$

80.30 °C is the final temperature.

b) Energy flows from higher temperature to lower temperature.Whenever two bodies with different energies and temperature come in contact. And the resulting temperature of both bodies will less then the body with high temperature and will be more then the body with lower temperature.

So, is our final temperature of both aluminium and coffee that is 80°C less than initial temperature of coffee and more than the initial temperature of the aluminum.

8 0

3 years ago

Colorful fireworks often involve the decomposition of barium nitrate and potassium chlorate and the reaction of the metals magne

Fynjy0 [20]

Fireworks owe their colors to reactions of combustion of the metals present. When Mg and Al burn, they emit a white bright light, whereas iron emits a gold light. Besides metals, oxygen is necesary for the combustion. The decomposition reactions of barium nitrate and potassium chlorate provide this element. At the same time, barium can burn emitting a green light.

(a) Barium nitrate is a salt formed by the cation barium Ba²⁺ and the anion nitrate NO₃⁻. Its formula is Ba(NO₃)₂. Potassium chlorate is a salt formed by the cation potassium K⁺ and the anion chlorate ClO₃⁻. Its formula is KClO₃.

(b) The balanced equation for the decomposition of potassium chloride is:

2KClO₃(s) ⇄ 2KCl(s) + 3O₂(g)

(c) The balanced equation for the decomposition of barium nitrate is:

Ba(NO₃)₂(s) ⇄ BaO(s) + N₂(g) + 3O₂(g)

(d) The balanced equations of metals with oxygen to form metal oxides are:

2 Mg(s) + O₂(g) ⇄ 2 MgO(s)

4 Al(s) + 3 O₂(g) ⇄ 2 Al₂O₃(s)

4 Fe(s) + 3 O₂(g) ⇄ 2 Fe₂O₃(s)

5 0

3 years ago

A covalent bond between an oxygen atom and a hydrogen atom is best described as _____.

Igoryamba

The answer is most likely nonmetals. :)

7 0

3 years ago

The Thompson analogy titled "The Carpet-Seed Children Analogy" attempts to deal with the issue of failed ____________________(A)

vazorg [7]

Answer: (D) contraception

Explanation:

8 0

3 years ago

Which of the following is a precipitation reaction?

erik [133]

Answer:

The precipitated are option a and d.

Explanation:

2 LiI(aq) +Hg2(NO3)2(aq) → Hg2I2(s) ↓ + 2 LiNO3(aq)

Cation Hg2+ 2 in the presence of iodide, a precipitated is formed.

Zn(s) + 2AgNO3(aq) → 2 Ag(s) ↓ +Zn(NO3)2(aq)

Zinc starts to get rid, and some white particles also stick to it. Afterwards the solution becomes cloudy and a precipitate appears, which is the solid silver

3 0

3 years ago

Practice question 1 How many moles are in 5.64e25 atoms of iron (Fe)?​

Practice question 1 How many moles are in 5.64e25 atoms of iron (Fe)?