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Levart [38]
3 years ago
15

Hydrogen burns exothermically in oxygen

Chemistry
1 answer:
Oliga [24]3 years ago
8 0

Answer:

C. -486 kJ/mol

Explanation:

Enthalpy change equals bonds broken (reactants) minus bonds formed (products)

Bonds broken = 2 H-H bonds + 1 O=O double bond = 2(436) +498 = 1,370 kJ/mol

Bonds formed = 4 O-H bonds = 4(464) = 1,856 kJ/mol

Bonds broken - bonds formed = 1,370 - 1,856 = -486 kJ/mol

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Elements with similar properties are located
Nataly [62]
Those elements with similar properties are in the same column.
4 0
4 years ago
What is the difference between a substance and mixture ?
snow_lady [41]

Explanation:

Matter can be categorized into substances and mixtures.

Matter is anything that has mass and occupies spaces.

Substances are distinct matter with the following properties:

  • All parts are the same throughout i.e homogeneous
  • Their composition is definite
  • They cannot be easily separated or broken down into simpler substances by physical means
  • Separation by physical means is not easy
  • They have a unique set of physical properties.

Mixtures have the following properties:

  • Their composition is indefinite i.e they consist of two or more elements and/or compounds in any proportion by mass
  • Their constituents retains their identity
  • They can easily be separated by physical means
  • They have a broad range of physical properties.

Learn more:

Mixtures brainly.com/question/1446244

#learnwithBrainly

6 0
4 years ago
Use the table on the right to calculate each required quantity
ValentinkaMS [17]

(1) The quantity of heat required to melt 175 g Cu is 35.88 kJ.

(2) The substance that releases 21.2 kJ of energy when 1.42 mol of it freezes is iron.

<h3>What is heat of fusion?</h3>

Heat of fusion is the energy required to melt 1 mole of a substance.

<h3>What is heat of vaporization?</h3>

The heat energy required to vaporize 1 mole of a substance has been heat of vaporization.

Heat of fusion of copper (Cu) is given as 13 kJ/mol

Number of  moles of 175 g of copper = 175/63.5 = 2.76 moles

Q = nΔH

Q = 2.76 mol  x 13 kJ/mol = 35.88 kJ

Thus, the quantity of heat required to melt 175 g Cu is 35.88 kJ.

<h3>Heat of fusion of the substance</h3>

ΔH(fus) = Q/n

where;

  • n is number of moles
  • Q is quantity of heat released

ΔH(fus) = 21.2 kJ / 1.42 mol

ΔH(fus) = 14.93 kJ/mol

From the table the substance with latent heat of fusion of 14.9 kJ/mol is iron.

Thus, the substance that releases 21.2 kJ of energy when 1.42 mol of it freezes is iron.

Learn more heat of fusion here: brainly.com/question/87248

#SPJ1

3 0
2 years ago
How many moles of gas are contained in a 50.0 L cylinder at a pressure of 100.0 atm and a temperature of 35.0°C?
grigory [225]

Answer:

n = 2 moles (1 sig-fig)

Explanation:

Using the Ideal Gas Law equation (PV = nRT), solve for n (= moles) and substitute data for ...

pressure = P(atm) = 100atm

volume =V(liters) = 50L

gas constant = R = 0.08206L·atm/mol·K

temperature = T(Kelvin) = °C + 273 = (35 + 273)K = 308K

PV = nRT => n = PV/RT = (100atm)(50L)/(0.08206L·atm/mol·K)(308K)

∴ n(moles) = 1.978moles ≅ 2 moles gas (1 sig-fig) per volume data (= 50L) that has only 1 sig-fig. (Rule => for multiplication & division computations round final answer to the measured data having the least number of sig-figs).

7 0
3 years ago
Heated bricks or blocks of iron were used long ago to warm beds. A 1.49 -kg block of iron heated to 155 Celsius would release ho
AlekseyPX
Specific heat capacity= Quantity of heat/massxΔT
Shc of iron (constant)= 0.4494J/³C for 1g
1.49kg=1490g
Q=1490x(22-155)x0.4494
Q=<span>89057.598J</span>
6 0
3 years ago
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