Answer: A) grinding coffee beans
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.
1. Grinding coffee : Only change in size takes place, thus a physical change
2. Baking a cake: the chemical reaction occurs by combination of flour with oxygen , thus a chemical change.
3.:converting water to hydrogen and oxygen: The decomposition iof water takes place, thus is a chemical change
4.Burning of coal: the chemical reaction occurs by combination of carbon with oxygen , thus a chemical change.
Answer:
1) Increasing the concentration of HCl [HCl] will increase the reaction rate.
2) The potential energy diagram is shown in the attached image.
3) Because of it is an irreversible reaction that goes to the forward direction . The reaction takes place till HCl dissolves Zn completely.
Explanation:
<em>Q1: State one change in reaction conditions, other than adding catalyst, that will increase the rate of the reaction.</em>
- The rate of the reaction, dissolving Zn in HCl, depends on the concentration of HCl.
Rate = k[HCl]².
<em>Rate ∝ [HCl]².</em>
- The rate is directly proportional to the concentration of HCl raised to the power 2,
<em>So, increasing the concentration of HCl [HCl] will increase the reaction rate.</em>
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<em>Q2: Draw a potential energy diagram for this reaction.</em>
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- Since the reaction releases energy that appears in the products side. So, the reaction is an exothermic reaction.
In an exothermic reaction, the energy of the reactants is higher than that of the products.
<em>The potential energy diagram is shown in the attached image.</em>
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<em>Q3: Explain why this reaction will not reach equilibrium.</em>
Because of it is an irreversible reaction that goes to the forward direction . The reaction takes place till HCl dissolves Zn completely.
It is determining which genes are linked to specific disease
The heat absorbed by water in calories is 1760 calories or 7367.36 joules.
To solve this question, we need to determine the heat formula.
Q = m.c.ΔT
where Q is total heat absorbed or released, m is mass, c is heat constant and ΔT is the different temperature.
From the question above, we know that:
the specific heat of water is 1 calorie per gram per Celsius degree.
m = 32 g
T1 = 25⁰C
T2 = 80⁰C
By using the heat formula, we can determine the heat absorbed by water
Q = m.c.ΔT
Q = 32 . 1 . (T2 - T1)
Q = 32 (80 - 25)
Q = 32 (55)
Q = 1760 calories
Hence, the heat absorbed by water in calories is 1760 calories.
Converting calories to joules means that it will be multiplied by 4.186
Q = 1760 x 4.186 joules
Q = 7367.36 joules
the heat absorbed by water in calories is 7367.36 joules.
Learn more heat at: brainly.com/question/16559442
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