Answer:
the color of the litmus paper will turn into blue color because sodium carbonate is basic in nature
The empirical formula for pyrite is FeS2.
HOW TO CALCULATE EMPIRICAL FORMULA:
- The empirical formula represents the simplest whole number ratio of constituents element of a compound. The empirical formula of pyrite can be calculated as follows:
46.5 mass % Fe = 46.5g of Fe
53.5 mass % S = 53.5g of S
- Next, we divide each element's mass value by its molar mass
Fe = 46.5g ÷ 56g/mol = 0.83mol
S = 53.5g ÷ 32g/mol = 1.67mol
- Next, we divide each mole value by the smallest (0.83mol)
Fe = 0.83mol ÷ 0.83 = 1
S = 1.67mol ÷ 0.83 = 2.014
Approximately, the ratio of Fe to S is 1:2. Therefore, the empirical formula of pyrite is FeS2.
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Answer : The amount of heat evolved by a reaction is, 4.81 kJ
Explanation :
Heat released by the reaction = Heat absorbed by the calorimeter + Heat absorbed by the water
![q=[q_1+q_2]](https://tex.z-dn.net/?f=q%3D%5Bq_1%2Bq_2%5D)
![q=[c_1\times \Delta T+m_2\times c_2\times \Delta T]](https://tex.z-dn.net/?f=q%3D%5Bc_1%5Ctimes%20%5CDelta%20T%2Bm_2%5Ctimes%20c_2%5Ctimes%20%5CDelta%20T%5D)
where,
q = heat released by the reaction
= heat absorbed by the calorimeter
= heat absorbed by the water
= specific heat of calorimeter = 
= specific heat of water = 
= mass of water = 254 g
= change in temperature = 
Now put all the given values in the above formula, we get:
![q=[(783J/^oC\times -2.28^oC)+(254g\times 4.184J/g^oC\times -2.28^oC)]](https://tex.z-dn.net/?f=q%3D%5B%28783J%2F%5EoC%5Ctimes%20-2.28%5EoC%29%2B%28254g%5Ctimes%204.184J%2Fg%5EoC%5Ctimes%20-2.28%5EoC%29%5D)

Therefore, the amount of heat evolved by a reaction is, 4.81 kJ
Answer:
H2SO4 + Al(OH)3 = Al2(SO4)3 + H2O
Explanation:
Molar mass :
NaBr = 103 g/mol
Pb(NO3)2 = 331.20 g/mol
<span><span /><span>Balanced chemical equation :
</span></span>2 NaBr + 1 Pb(NO3)2 = 2 NaNO3 + 1 PbBr<span>2
</span><span>
2*103 g NaBr ------------> 1 * 331.20 g Pb(NO3)2
g NaBr -------------------> 311 g Pb(NO3)2
331.20 g = 2*103*311
331.20 g = 64066
mass ( NaBr ) = 64066 / 331.20
mass ( naBr) = 193,43 g of NaBr
hope this helps!.
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