Answer:
Mass of hydrogen produced = 2.1 g
Mass of excess reactant left = 25.2 g
Explanation:
Given data:
Mass of Mg = 50.0 g
Mass of HCl = 75.0 g
Mass of hydrogen produced = ?
Mass of excess reactant left = ?
Solution:
Chemical equation:
Mg + 2HCl → MgCl₂ + H₂
Number of moles of Mg:
Number of moles = mass/molar mass
Number of moles = 50 g/ 24 g/mol
Number of moles = 2.1 mol
Number of moles of HCl:
Number of moles = mass/molar mass
Number of moles = 75 g/ 36.5 g/mol
Number of moles = 2.1 mol
now we will compare the moles of hydrogen gas with both reactant.
Mg : H₂
1 : 1
2.1 : 2.1
HCl : H₂
2 : 1
2.1 : 1/2×2.1 = 1.05 mol
HCl is limiting reactant and will limit the yield of hydrogen gas.
Mass of hydrogen:
Mass = number of moles × molar mass
Mass= 1.05 mol ×2 g/mol
Mass = 2.1 g
Mg is present in excess.
Mass of Mg left:
HCl : Mg
2 : 1
2.1 : 1/2×2.1 = 1.05
Out of 2.1 moles of Mg 1.05 react with HCl.
Moles of Mg left = 2.1 mol - 1.05 mol = 1.05 mol
Mass of Mg left:
Mass = number of moles × molar mass
Mass = 1.05 mol × 24 g/mol
Mass = 25.2 g
Particles of carbon can also be called co2 or also a greenhouse gas. The emission of carbon into the atmosphere causes air pollution and can also lead to global warming.
D. Catalysts get used up in the formation of the product.
Catalysts are never used up in a reaction.
1.55 g/L; 9.503 03 × 10^20 mL
<em>Part 1.
</em>
<em>Step 1</em>. Convert <em>kilograms to grams</em>.
1.55 kg × (1000 g/1 kg) = 1550 g
<em>Step 2</em>. Convert <em>cubic metres to litres</em>.
1 m^3 × (1000 L/1 m^3) = 1000 L
<em>Step 3</em>. Divide <em>grams by litres</em>
1.55 kg/1 m^3 = 1550 g/1000 L = 1.55 g/L
<em>Part 2.</em>
<em>Step 1</em>. Convert <em>cubic kilometres to cubic metres</em>
950 303 km^3 × (1000 m/1 km)^3 = 9.503 03 × 10^14 m^3
<em>Step 2</em>. Convert <em>cubic metres to litres</em>.
9.503 03 × 10^14 m^3 × (1000 L/1 m^3) = 9.503 03 × 10^17 L
<em>Step 3</em>. Convert <em>litres to millilitres</em>.
9.503 03 × 10^17 L × (1000 mL/1 mL) = 9.503 03 × 10^20 mL
Freezing
Explanation:
This change in state when surface of a lake changes to hard ice is known as freezing.
- When a solid is heated, it melts and changes to a liquid. On further heating, it changes to vapor and the randomness increases.
- When a liquid is cooled below its freezing point, it changes to a solid such as ice for water.
- The phase change is known as freezing.
Learn more:
Phase change brainly.com/question/1875234
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