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vazorg [7]
2 years ago
13

If 89.6 joules of heat are needed to heat 20.0 grams of iron from 30.0°c to 40.0°c, what is the specific heat of the iron in jg?

°c jg?°c ?
Chemistry
1 answer:
klasskru [66]2 years ago
6 0
The relation of heat (Q), mass (m), and change of temperature (ΔT) is given by the formula:

Q = m*Cs*ΔT, where Cs is the specific heat of the material.

Then, given than you know Q, m and ΔT, you can solv for Cs:

Cs = Q / (m*ΔT)

Cs = 89.6 J / [20 grams * (40.0°C - 30.0°C)] = 0.448 J / g * °C.
 


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1‑propanol ( n ‑propanol) and 2‑propanol (isopropanol) form ideal solutions in all proportions. Calculate the partial pressure a
Alex777 [14]

Answer:

y_{prop} = 0.134; y_{iso} = 0.866

The partial pressure of isopropanol = 34.04 Torr; The partial pressure of propanol = 5.26 Torr

Explanation:

For each of the solutions:

mole fraction of isopropanol  (x_{iso}) = 1 - mole fraction of propanol (x_{prop}).

Given: mole fraction of propanol = 0.247. Thus, the mole fraction of isopropanol = 1 - 0.247 = 0.753.

Furthermole, the partial pressure of isopropanol = x_{iso}*vapor pressure of isopropanol = 0.753*45.2 Torr = 34.04 Torr

The partial pressure of propanol = x_{prop}*vapor pressure of propanol = 0.247*20.9 Torr = 5.16 Torr

Similarly,

In the vapor phase,

The mole fraction of propanol (y_{prop}) = \frac{P_{prop} }{P_{prop}+P_{iso}}

Where, P_{prop} is the partial pressure of propanol and P_{iso} is the partial pressure of isopropanol.

Therefore,

y_{prop} = 5.26/(34.04+5.16) = 0.134

y_{iso} = 1 - 0.134 = 0.866

5 0
2 years ago
A 30.0 g sample of a metal was heated in a hot water bath to 80°c. it was then quickly transferred to a coffee-cup calorimeter.
Annette [7]
when the metal  is lost heat and the calorimeter of water is gained the heat 

and when the heat lost = the heat gained so,

(M*C*ΔT)m =  (M*C*ΔT)w

when Mm= mass of the metal = 30 g 

Δ Tm = (80-25) = 55 °C

and Mw = mass of water = 100 g  

Cw is the specific heat of water = 4.181 J/g.°C

ΔTw = (25-20) = 5 °C

so by substitution:

∴ 30* Cm*55 = 100 * 4.181 * 5 

∴Cm (specific heat of metal) = (100*4.181*5)/(30*55) 

∴C of metal = 1.267 J/g.°C
3 0
2 years ago
Read 2 more answers
Calculate the number of kilojoules of energy required to convert 50.0 grams of solid DMSO initially at a temperature of 19.0°C t
GuDViN [60]

Answer:

20.79 kilojoules

Explanation:

Using Q = m×c×∆T

Where;

Q = Quantity of heat (J)

c = specific heat capacity of solid DMSO (1.80 J/g°C)

m = mass of DMSO

∆T = change in temperature

According to the provided information, m= 50g, initial temperature = 19.0°C, final temperature= 250.0°C

Q = m×c×∆T

Q = 50 × 1.80 × (250°C - 19°C)

Q = 90 × 231

Q = 20790 Joules

To convert Joules to kilojoules, we divide by 1000 i.e.

20790/1000

= 20.79 kilojoules

Hence, 20.79 kilojoules of energy is required to convert 50.0 grams of solid DMSO to gas.

4 0
2 years ago
A student pours exactly 26.9 mL of HCl acid of unknown molarity into a beaker. The student then adds 2 drops of the indicator an
Assoli18 [71]
a.
Acids react with bases and give salt and water and the products.

Hence, HCl reacts with NaOH and gives NaCl salt and H₂O as the products. The reaction is,
            HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

To balance the reaction equation, both sides hould have same number of elements.

Left hand side,                                             Right hand side,
             
H atoms = 2                                               H atoms = 2
            Cl atoms = 1                                               Cl atoms = 1
            Na atoms = 1                                               Na atoms = 1 
           O atoms = 1                                                   O atoms = 1

Hence, the reaction equation is already balanced.

b. 
Molarity (M)= moles of solute (mol) / Volume of the solution (L)
 
          HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

Molarity of NaOH = <span>0.13 M
</span>Volume of NaOH added = <span>43.7 mL
Hence, moles of NaOH added = 0.13 M x 43.7 x 10</span>⁻³ L
                                                 = 5.681 x 10⁻³ mol

Stoichiometric ratio between NaOH and HCl is 1 : 1

Hence, moles of HCl = moles of NaOH
                                    = 
5.681 x 10⁻³ mol

5.681 x 10⁻³ mol of HCl was in <span>26.9 mL.

Hence, molarity of HCl = </span>5.681 x 10⁻³ mol / 26.9 x 10⁻³ L
                                     = 0.21 M
6 0
2 years ago
6. Cross-cuts are best made with which of the following types of knife? A. Utility knife B. Scaler C. Paring knife D. Chef's kni
zaharov [31]

Answer:

A

Explanation:

Utility knife

8 0
2 years ago
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