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What is the specific heat capacity of a 70 g sample of an unknown metal that releases 6700J of heat when it cools from 90 to 25

swat32

Q = mCpΔT —> Solve for Cp —> Cp = q/mΔT

q = -6700 J (negative because it released heat
m = 70 g
ΔT = Final temp - initial temp = 25 - 90 = -65°C

Cp = -6700 J / (70 g)(-65°C) = 1.47 J/g°C

3 0

3 years ago

Which type of mass movement makes pattern of wrinkles, or terraces, on hillsides

kondor19780726 [428]

Erosion is the correct answer

8 0

4 years ago

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Which statement is true about a polyatomic ion?

Charra [1.4K]

<span>Among the given choices, which among them tells us the truth about the polyatomic ion. The polyatomic ions are charged molecules or formula units that are composed of many atoms. From the given choices, the answer would be letter C. It is made of atoms that are covalently bonded together. When we say covalently bonded, the atoms are shared among the atoms composing the formula unit. </span>

5 0

3 years ago

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Blast furnaces extra pure iron from the Iron(IIl)oxide in iron ore in a two step sequence. In the first step, carbon and oxygen

OLga [1]

Answer:

5.9 kg

Explanation:

We must work backwards from the second step to work out the mass of oxygen.

1. Second step

Mᵣ: 55.84

Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂

m/kg: 7.0

(a) Moles of Fe

$\text{Moles of FeO} = \text{7000 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.84 g Fe}} = \text{125 mol Fe}$

(b) Moles of CO

$\text{Moles of CO} = \text{125 mol Fe} \times \dfrac{\text{3 mol CO}}{\text{2 mol Fe}} = \text{188 mol CO}$

However, this is the theoretical yield.

The actual yield is 72. %.

We need more CO and Fe₂O₃ to get the theoretical yield of Fe.

(c) Percent yield

$\begin{array}{rcl}\text{Percent yield} &=& \dfrac{\text{ actual yield}}{\text{ theoretical yield}} \times 100 \, \%\\\\ 72. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.72 &= &\dfrac{\text{188 mol}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{188 mol}}{0.72}\\& = & \textbf{261 mol}\\\\\end{array}$

We must use 261 mol of CO to get 7.0 kg of Fe.

2. First step

Mᵣ: 32.00

2C + O₂ ⟶ 2CO

n/mol: 261

(a) Moles of O₂

$\text{Moles of O}_{2} = \text{261 mol CO} \times \dfrac{\text{1 mol O}_{2}}{\text{2 mol CO}} = \text{131 mol O}_{2}$

(b) Mass of O₂

$\text{Mass of O}_{2}= \text{131 mol O }_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \text{4180 g O}_{2}$

However, this is the theoretical yield.

The actual yield is 71. %.

We need more C and O₂ to get the theoretical yield of CO.

(c) Percent yield

$\begin{array}{rcl}71. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.71 &= &\dfrac{\text{4180 g}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{4180 g}}{0.71}\\\\& = & \text{5900 g}\\& = & \textbf{5.9 kg}\\\end{array}$

We need 5.9 kg of O₂ to produce 7.0 kg of Fe.

6 0

4 years ago

1. The ___________ nervous system works without you thinking about it. It is automatically controlled. A.central B.autonomic 2.

bogdanovich [222]

Answer:

central

spinal cord

sensory

Explanation:

i believe these are the correct answers

7 0

3 years ago