Over all the size of the crystal depends on how fast magma will harden over time if the magma cools slowly the crystal will be larger than they would if the magma cooled faster
Option (a) is correct.
A reducing agent is the one which loses electrons to other substance.
Here, Zn has oxidation number 0 in the L.H.S of the equation, but on R.H.S its oxidation number is +2 i.e. it Zn has donated two of its electrons to
.
Hence, Zn is the reducing agent here.
Answer:
1.The Aluminum block
2.its surroundings absorb energy from it.
Explanation:
In this question it is important to remember that density of an object is the mass of that object divided by its volume.
The expression applied here is density=mass/volume
Given that the mass is constant,lets say mass= m=1g
and density of aluminum=2.7g/cm³ and that of iron is 7.8 g/cm³ then volume=?
Volume=mass/density
Volume of aluminum= 1/2.7 =0.3704 cm³
Volume of iron = 1/7.8 =0.1282 cm³
Here we see volume of Aluminum block is the largest.
2.As water in an ice cube tray freezes, its surroundings absorb energy from it.When the water freezes, latent heat of freezing is given out to the surrounding.When water is freezing, it stays at a constant temperature of 0°C, the heat energy released ensures that there is no cooling past 0 °C.
I think the reaction that is occurring is CuSO₄(aq)+Na₂CO₃(aq)⇒CuCO₃(s)+Na₂SO₄(aq). Water in the hydrate will just become part of water in solution so it does not really matter for this question.
SInce we now know the balanced chemical equation, you can use stoichiometry to find the amount of reactants needed to produce 5g CuCO₃.
The first step to any stoichiometry question is to convert the mass given into moles. To do this you have to divide the mass by the molar mass of the compound the mass is referring to. The molar mass of CuCO₃ is 123.5g/mol so you have to divide 5g by 123.5g/mol to get 0.04047 moles of CuCO₃.
The next step in this qustoin is to find the number of moles of each reactant using the moles of product we found in the first step. To do this, we need go back and look at the equation to find the molar ratios which is shown through the coefficients. Since all of the coeficients in the chemical equation is 1, we know the molar ratios are all `1 to 1 and therefore the number of moels of each reactant is equal to the number of moles of the product found in step one. This means that you started off with 0.04047 moles of both CuSO₄ and Na₂CO₃.
The final step is to multiply the number moles of each reactant by its molar mass. the molar mass of CuSO₄ is 159.6g/mol and the molar mass of Na₂CO₃ is 106g/mol. When you multiply 0.04047mol by 159.6g/mol you get 6.4g and when you multiply 0.04047mol by 106g/mol you get 4.29g.
Therefore you started with 6.4g of CuSO₄ and 4.29g of Na₂CO₃.
I hope this helps.
