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2 years ago

Help with this please.

Chemistry

1 answer:

chubhunter [2.5K]2 years ago

6 0

Answer:

Explanation:

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Calculate the energy, in joules, to heat two cubes (silver and copper), each with a volume of 10.0cm, from 15 C to 25 C

Julli [10]

Answer:

For Silver , The heat absorbed = 246.75 J

For Copper , The heat is = 343.42 J

Explanation:

The change in temperature is calculated by:

$\Delta T=T_{2}-T_{1}$

T2 = 25 C

T1 = 15 C

$\Delta T=25-15$

$\Delta T=10^{0}C$

The energy in Joules can be calculated using :

$q=mc\Delta T$

here , m = mass of the substance

c = the heat capacity

q = heat absorbed / released

We need to calculate the mass , In order to determine the value of "q".

Calculation for Silver :

The mass is calculated from the density of the element.

density of Silver = 10.5 g/ml (look at the table of density)

Volume of Cube = 10 cm^3 (given)

1 cm^3 = 1 mL

10 cm^3 = 10 mL

The mass can be calculated using the formula:

$mass = density\times Volume$

$mass = 10.5\times 10$

$mass = 105grams$

Insert the value of m , c, T in the equation.

for Silver the value of "c"= 0.235 J/gC (Look at the table)

$q=mc\Delta T$

$q=105\times 0.235\times 10$

$q=246.75J$

Calculation for Copper:

Again first calculate the mass of Copper.

Density of Copper = 8.92 g/ml

Volume = 10 mL

$mass = density\times Volume$

$mass = 8.92\times 10$

$mass = 89.2grams$

Insert the value of m , c, T in the equation.

for Silver the value of "c"= 0.385 J/gC (Look at the table)

$q=mc\Delta T$

$q=89.2\times 0.385\times 10$

$q=343.42J$

8 0

3 years ago

Powdered aluminum is used in the thermite reaction for welding metals. what role does the powdered aluminum play in this reactio

BigorU [14]

Powdered aluminum serves the reducing agent for this reaction. Aluminum powder is known as a powerful reducing agent. Iron(iii) ions would have greater electron affinity as compared to a metallic aluminum thus it would easily gain electrons from aluminum making it less positive in this case formed into a neutral atom. The chemical reaction is 

Fe2O3 + 2Al = Al2O3 + 2Fe.

Oxygen in the oxide compound does not participate in this redox reaction, as it is not changed chemically. Fe2O3 is an ionic compound which has of Fe[3+] ions and O[2-] ions. So, the net ionic reaction would be

Fe3+ + Al + 3O2- = Al3+ + Fe + 3O2- 

The ionization energy of aluminum is greater than that of iron, so the said reaction would generate large amount of heat which is needed in welding.

5 0

3 years ago

A same of gas in a rigid container is at 25.0Cand 1.00atm. What is the pressure of the sample when heated to 220.0C

Crazy boy [7]

Answer:

1.654 atm.

Explanation:

We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

If n and V are constant, and have different values of P and T:

(P₁T₂) = (P₂T₁)

Knowing that:

P₁ = 1.0 atm, T₁ = 25°C + 273 = 298 K,

P₂ = ??? atm, T₂ = 220°C + 273 = 493 K,

Applying in the above equation

(P₁T₂) = (P₂T₁)

∴ P₂ = (P₁T₂)/(T₁) = (1.0 atm)(493 K)/(298 K) = 1.654 atm.

7 0

3 years ago

3. Using the solubility of ionic compounds table and/or the solubility rules,

Klio2033 [76]

Answer:

Sugar, sodium chloride, and hydrophilic proteins

6 0

3 years ago

How many moles are in 281 g of Ca(OH)2?

Natasha_Volkova [10]

Answer:

3.79 moles

Explanation:

To convert moles to gams of a substance we need to find the molar mass of the substance. For Ca(OH)₂ th molar mass is:

1Ca = 40.08g/mol

2O = 2*16g/mol = 32g/mol

2H = 2*1.01g/mol = 2.02g/mol

The molar mass is:

40.08g/mol + 32g/mol + 2.02g/mol = 74.1g/mol

And moles are:

281g * (1mol / 74.1g) =

<h3>3.79 moles</h3>

5 0

3 years ago