Answer:
2.8g/cm³
Explanation:
Given parameters:
Mass of cube = 42g
Volume of cube = 15cm³
Unknown:
Density of the cube = ?
Solution:
Density is defined as the mass per unit volume of a substance. It is mathematically expressed as:
Density =
So;
Density = = 2.8g/cm³
13.5g
Explanation:
Given parameters:
Mass of Na = 10g
Mass of O₂ = 10g
Unknown:
Mass of products formed = ?
Balanced equation = ?
Solution:
The balanced chemical equation is shown below:
4Na + O₂ ⇒ 2Na₂O
In any reaction, the specie in short supply determines the extent of the reaction.
This reaction is not an exclusion. We need to first determine the specie in short supply and use it to estimate the amount of product since we have a 100% yield which signifies that all was used up.
let us convert to moles;
Number of moles of Na = = 0.435mole
Number of moles of O₂ = = 0.313mole
From the given equation;
4 moles of Na requires 1 mole of O₂;
0.435 moles of Na will require = 0.11 moles
But the given amount O₂ is 0.313, this is an excess of 0.313 - 0.11 = 0.203moles
We see that Na is the limiting reagent;
4 moles of Na gives 2 mole of Na₂O
0.435 moles of Na will give = 0.22 moles
Mass of Na₂O = number of moles x molar mass = 62 x 0.22 = 13.5g
learn more:
Number of moles brainly.com/question/1841136
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Answer:
The heat absorbed by the sample of water is 3,294.9 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
The sensible heat of a body is the amount of heat received or transferred by a body when it undergoes a temperature variation (Δt) without there being a change of physical state (solid, liquid or gaseous). Its mathematical expression is:
Q = c * m * ΔT
Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case:
Replacing:
Q= 4.184 * 45 g* 17.5 C
Solving:
Q=3,294.9 J
<u><em>The heat absorbed by the sample of water is 3,294.9 J</em></u>
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