Answer:
2.00 × 10⁻³ g
Explanation:
Step 1: Write the balanced decomposition reaction
2 NaHCO₃ ⇒ Na₂CO₃ + CO₂ + H₂O
Step 2: Calculate the moles corresponding to 0.0118 g of Na₂CO₃
The molar mass of Na₂CO₃ is 105.99 g/mol.
0.0118 g × 1 mol/105.99 g = 1.11 × 10⁻⁴ mol
Step 3: Calculate the moles of H₂O produced with 1.11 × 10⁻⁴ moles of Na₂CO₃
The molar ratio of Na₂CO₃ to H₂O is 1:1. The moles of H₂O produced are 1/1 × 1.11 × 10⁻⁴ mol = 1.11 × 10⁻⁴ mol.
Step 4: Calculate the mass corresponding to 1.11 × 10⁻⁴ moles of H₂O
The molar mass of H₂O is 18.02 g/mol.
1.11 × 10⁻⁴ mol × 18.02 g/mol = 2.00 × 10⁻³ g
Answer:
A glass of mineral water is not pure water.
Explanation:
Pure chemical substances
Pouring water into a glass from a bottle
Food and drink may be advertised as ‘pure’. For example, you may see cartons of ‘pure orange juice’ or ‘pure mineral water’. This means that nothing else was added to the orange juice or mineral water during manufacture. However, these substances are not pure to a scientist. In science, a pure substance contains only one element or compound.
Mineral water is mostly water, but there are other substances mixed with it. These are the ingredients that you see listed on the bottle’s label.
Nitrogen followed by oxygen
Answer:
Option A. to build new cells.
Explanation:
All living things need nitrogen for the production of new cell because nitrogen is the main structural component of the cell. Protein is made up of amino acid and amino acid made of nitrogen. Without nitrogen atom, enzymes formation is impossible and we know that enzymes are necessary to speed up the chemical process. So nitrogen is very important for living organisms.
