Answer:

Explanation:
We are asked to find how many kilojoules of energy would be required to heat a block of aluminum.
We will use the following formula to calculate heat energy.

The mass (m) of the aluminum block is 225 grams and the specific heat (c) is 0.897 Joules per gram degree Celsius. The change in temperature (ΔT) is the difference between the final temperature and the initial temperature.
- ΔT = final temperature - inital temperature
The aluminum block was heated from 23.0 °C to 73.5 °C.
- ΔT= 73.5 °C - 23.0 °C = 50.5 °C
Now we know all three variables and can substitute them into the formula.
- m= 225 g
- c= 0.897 J/g° C
- ΔT= 50.5 °C

Multiply the first two numbers. The units of grams cancel.



Multiply again. This time, the units of degrees Celsius cancel.


The answer asks for the energy in kilojoules, so we must convert our answer. Remember that 1 kilojoule contains 1000 joules.

Multiply by the answer we found in Joules.




The original values of mass, temperature, and specific heat all have 3 significant figures, so our answer must have the same. For the number we found, that is the tneths place. The 9 in the hundredth place tells us to round the 1 up to a 2.

Approximately <u>10.2 kilojoules</u> of energy would be required.
Answer:
a) Li2CO3
b) NaCLO4
c) Ba(OH)2
d) (NH4)2CO3
e) H2SO4
f) Ca(CH3COO)2
g) Mg3(PO4)2
f) Na2SO3
Explanation:
a) 2Li + CO3 ↔ Li2CO3
b) NaOH * HCLO4 ↔ NaCLO4 + H2O
c) Ba + 2H2O ↔ Ba(OH)2 +
d) 2NH4 + H2CO3 ↔ (NH4)2CO3 + H2O
c) SO2 + NO2 +H2O ↔ H2SO4 + NOx
f) 2CH3COOH + CaO ↔ Ca(CH3COOH)2 + H2O
g) 3MgO + 2H3PO4 ↔ Mg3(PO4)2 + H2O
h) NaOH + H2SO3 ↔ Na2SO3 + H2O
Answer:

Explanation:
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In this case, since the net ionic equation of a chemical reaction shows up the ionic species that result from the simplification of the spectator ions, which are those at both reactants and products sides, we take into account that aqueous species ionize into ions whereas liquid, solid and gas species remain unionized. In such a way, for the reaction of cesium phosphate and silver nitrate we can write the complete molecular equation:

Whereas the three aqueous salts are ionized in order to write the following complete ionic equation:

In such a way, since the cesium and nitrate ions are the spectator ions because of the aforementioned, the net ionic equation turns out:

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Moles are the division of the mass and the molar mass. The moles of mercury (ii) oxide in the decomposition reaction needed to produce oxygen are 0.781 moles.
<h3>What is a decomposition reaction?</h3>
A decomposition reaction is a breakdown of the reactant into simpler products. The decomposition of mercury (ii) oxide can be shown as:
2HgO(s) → 2Hg(l) + O₂(g)
From the reaction, it can be said that 2 moles of mercury (ii) oxide decomposes to produce 1 mole of oxygen.
The moles of oxygen that needs to be produced are calculated as:
Moles = mass ÷ molar mass
= 12.5 gm ÷ 32 gm/mol
= 0.39 moles
0.39 moles of oxygen are needed to be produced.
From the stoichiometric coefficient of the reaction, the moles of HgO is calculated as: 2 × 0.39 = 0.781 moles
Therefore, 0.781 moles of HgO are required in the reaction.
Learn more about moles here:
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Answer:

Explanation:
Molarity is a measure of concentration in moles per liter.

The molarity of the solution is 1.2 M NaNO₃ or 1.2 moles NaNO₃ per liter. There are 0.25 liters of the solution. The moles of solute are unknown, so we can use x.
- molarity= 1.2 mol NaNO₃/L
- liters of solution=0.25 L
- moles of solute =x

We are solving for x, so we must isolate the variable, x. It is being divided by 0.25 liters. The inverse of division is multiplication, so we multiply both sides by 0.25 L.


The units of liters cancel, so we are left with the units moles of sodium nitrate.


There are 0.3 moles of sodium nitrate.