The best answer to this question is letter b) the shirt reflects the yellow wavelengths. Someone's shirt may look yellow because the dye molecules of the shirt absorbs the other colors, and it is yellow that is the only color that is reflected by the shirt.
Answer:
Increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time)
Explanation:
The chemical reaction between baking soda and vinegar in water is shown in the chemical reaction equation below;
NaHCO3(aq) + CH3COOH(aq) ----->CO2(g) + H2O(l) + CH3COONa(aq)
The chemical name of baking soda is sodium bicarbonate (NaHCO3) while vineager is a dilute acetic acid (CH3COOH) solution. This reaction provides a very easy set up in which we can study the effect of concentration on the rate of chemical reaction.
We must have it behind our minds that increase in the concentration of reactant species increases the rate of chemical reaction. Secondly, the rate of the reaction between baking soda and vinegar can be monitored by observing the volume of CO2 evolved and how quickly it evolves from the reaction mixture.
We can now postulate a hypothesis which states that; 'increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time).'
If we go ahead to subject this hypothesis to experimental test, it will be confirmed to be true because a greater volume of CO2 will be evolved within a shorter time as the concentration of the reactants increases.
A mixture of hydrogen and oxygen would not need to have a certain ratio of hydrogen atoms to oxygen atoms to differ from the compound known as water.
<h3>Why is water a compound not a mixture?</h3>
A water molecule has 2 hydrogen atoms bonded chemically to oxygen atoms and has the formula H₂O.
In a chemical reaction, two atoms react together chemically to form a new product which means the reactants lose their individual properties and obtain new properties of the product formed.
Hence, water is a compound as hydrogen and oxygen atoms are bonded chemically to each other.
On the other hand, if oxygen and hydrogen form a mixture which is a physical change then they retain their individual properties in the mixture. They do not need to be in a specific ratio and there are no chemical changes taking place.
Chemical change determines if a substance is a mixture or a compound.
Thus, a mixture of hydrogen and oxygen is different from water if it doesn't have a certain ratio of hydrogen atoms to oxygen atoms.
Learn more about mixture:
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7.5 mol of hydrogen would be needed to consume the available nitrogen.
Explanation:
When hydrogen reacts with nitrogen, ammonia is formed as shown below;
3H₂ (g) + N₂ (g) → 2NH₃ (g)
As seen from the equation, every 3 moles of H₂ react with a mole of N₂ to form 2 moles of NH₃.
The limiting factor in a chemical reaction is the reactant that gets depleted first.
Because the molar mass of nitrogen gas is approximately 28g/mol, 70g of nitrogen gas would be 2.5 moles.
The reaction ratio of nitrogen to hydrogen in the reaction is 1 : 3. The reaction would require 2.5 * 3 (7.5) moles of hydrogen for a complete reaction.
However since there are only 7g on hydrogen, (Remember 1 mole of H₂ is approximately 2g), the available moles of H₂ is 7 / 2 = 3.5
3.5 moles fall short of the 7.5 moles of H₂ required for a complete reaction. H₂ gets depleted first before N₂. The reaction would require 4 more moles of H₂.
