I dont know what subject is this
Answer:
The mass, CO2 and CO3 from the limestone sample is discussed below in details.
Explanation:
(A) mass loss of sample of limestone after 20 min
= 0.8437g-0.5979g = 0.2458 g
From the given reaction of limestone, 2 mol of the sample gives 2 moles of CO 2.
Therefore
184.4 g ( molar mass of limestone) gives2× 44 g of carbon dioxide.
1 g of sample gives 88/184.4 g of carbon dioxide
Hence 0.2458 g sample gives
= 88/184.4 × 0.2458 g = 0.117 g carbon dioxide
(B) mole of CO 2 lost = weight/ molar mass
= 0.117 g / 44 g/mol =0.0027 mole
(C). 1 mol of limestone contain 2 mol of carbonate ion
From the reaction we know that carbonate ion of limestone is converted into carbondioxide
Hence lost carbonate ion = 0.2458 g
(D) we know that
1 mol limestone contain 1mol CaCO 3
Hence in sample present CaCO 3
= 1mole / 184.4 g × 0.8437 g= 0.00458 mol CaCO3
1. Physical
2. Chemical
3. Physical
4. Physical
5. Chemical
6. I really don't feel like doing 6, sorry.
7. False: energy to mass
11. False: change to exothermic
12. False: change to endothermic
Answer:

Explanation:
<em>Ferrous Sulphate</em>
<em> is generally found as Lime-Green Crystals. On heating, these crystals almost immediately turn white-yellow. They then, break down to produce an anhydrous mixture of Sulphur Trioxide </em>
<em>, Sulphur Dioxide </em>
<em> as well as Ferric Oxide </em>
<em>.</em>
<em>We can hence, frame a skeletal equation of this reaction and try to balance it.</em>
<em>Hence,</em>

<em>Now,</em>
<em>a)In order to balance it through the 'Hit &Trial Method', we'll follow a series of </em><em>steps</em><em>:</em>
<em>1. First, lets compare the number of Fe (Iron) atoms on the RHS and LHS. We find that, the no. of Fe Atoms on the RHS is twice the number of Fe Atoms on the LHS. We hence, add a co-effecient 2 beside </em>
.
<em>2. Now, Iron atoms, Sulphur Atoms and Oxygen atoms occur 2, 2, 8 respectively on both the sides:</em>
<em> Hence, As all the other elements as well as iron, balance, we've arrived upon our Balanced Equation :</em>
<em> </em>
<em>b) We know that, decomposition reactions are [generally] endothermic reactions in which Large Compounds </em><em>decompose </em><em>into smaller elements and compounds. Here, as Ferrous Sulphate </em><em>decomposes </em><em>into Sulphur Dioxide, Sulphur Trioxide and Ferric Oxide, the reaction that occurs here is </em><em>Decomposition Reaction.</em>
Step 1 - Discovering the ionic formula of Chromium (III) Carbonate
Chromium (III) Carbonate is formed by the ionic bonding between Chromium (III) (Cr(3+)) and Carbonate (CO3(2-)):

Step 2 - Finding the molar mass of the substance
To find the molar mass, we need to multiply the molar mass of each element by the number of times it appears in the formula of the substance and, finally, sum it all up.
The molar masses are 12 g/mol for C; 16 g/mol for O and 52 g/mol for Cr. We have thus:

The molar mass will be thus:

Step 3 - Finding the percent composition of carbon
As we saw in the previous step, the molar mass of Cr2(CO3)3 is 284 g/mol. From this molar mass, 36 g/mol come from C. We can set the following proportion:

The percent composition of Carbon is thus 12.7 %.