The lucky necklace as it can't be proven.
Answer:
The mass of a sample of iron that has had 300 J applied to it and heats up from 20 degrees Celsius to 40 degrees Celsius is 32.61 grams.
Explanation:
Calorimetry is the measurement and calculation of the measurement of heat changes exchanged by a body or a system produced in physical and chemical processes.
The sensible heat of a body is the amount of heat received or transferred by a body to produce a change in temperature but without a change in physical state.
The sensible heat in a constant pressure is calculated by:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c, and where ΔT is the temperature variation (ΔT=Tfinal - Tinitial)
In this case:
- c= 0.46

- m= ?
- Tfinal= 40 C
- Tinitial= 20 C
Replacing:
300 J= 0.46
* m* (40 - 20) C
Solving:
300 J= 0.46
* m* 20 C

m= 32.61 g
<u>Answer:</u>
<em>The option a termed as precipitation reaction is incorrectly labelled.
</em>
<u>Explanation:</u>
The chemical reactions are classified based on the reactants used and products formed in a reaction. They are decomposition reaction, single displacement reaction, double displacement reaction, acid-base neutralisation reaction, precipitation reaction, combustion reaction, redox reaction and organic reaction.
Among these, the given options are labelled as precipitation and combustion reaction. The one which is labelled as combustion reaction is correct because combustion reactions occur in the presence of oxygen only and the products of combustion reaction should include water, oxygen or carbon and heat.
The other option which is labelled as precipitation reaction is incorrect because precipitation reaction occurs when an ionic substance will come out of a solution due to heating it or stirring it making the solubility of the ionic substance in a solution zero such that it will come out as solid and form a layer at the bottom of the solution.
But in this case all the products are in aqueous state, there is absence of any ionic substance in solid state, so the option which is labelled as precipitation reaction is incorrectly labelled.
Answer:
Natural selection is a process in which organisms are fit to adapt and live in the environment. Natural selection was an idea developed by Charles Darwin, Darwin contributed this idea when he was studying birds and tortoises at the Galapagos Islands. He then wrote his famous book, <em><u>O</u></em><em><u>r</u></em><em><u>i</u></em><em><u>g</u></em><em><u>i</u></em><em><u>n</u></em><em><u> </u></em><em><u>o</u></em><em><u>f</u></em><em><u> </u></em><em><u>S</u></em><em><u>p</u></em><em><u>e</u></em><em><u>c</u></em><em><u>i</u></em><em><u>e</u></em><em><u>s</u></em><em><u>.</u></em> Evolution is also very similar, evolution is a process in which organisms reproduce and mutate in order to survive and adapt. As you can see, natural selection and evolution are alike in many ways.
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•Expert•
Brainly Community Contributor