Answer:
A) double replacement
Explanation:
Chemical equation:
NaCl +CaS → Na₂S + CaCl₂
Balanced chemical equation:
2NaCl +CaS → Na₂S + CaCl₂
The given reaction is double replacement reaction in which cation and anions of each reactant exchange with each other.
Double replacement:
It is the reaction in which two compound exchange their ions and form new compounds.
AB + CD → AD +CB
Other options are incorrect because,
Synthesis reaction:
It is the reaction in which two or more simple substance react to give one or more complex product.
AB → A + B
Single replacement:
It is the reaction in which one elements replace the other element in compound.
AB + C → AC + B
Decomposition reaction:
It is the reaction in which one reactant is break down into two or more product.
AB → A + B
Explanation:
Given parameters:
Mass of sample = 235g
Molecular mass of sample = 128.1g
Empirical formula = CH₂O
Unknown:
Mass of each element in the sample = ?
Solution:
To solve this problem, we must know that the empirical formula of any compound is the simplest ratio of the atoms it contains. This is not the true formula of the compound.
Molecular formula = (Empirical formula)ₙ
Let us find the molecular mass of the sample;
CH₂O = 12 + 2(1) + 16 = 30g
128.1 = (30)n
n = 4
The molecular formula of the compound is; (CH₂O)₄ = C₄H₈O₄
Now to find the grams of each element in the sample;
Express the molecular mass of each element and that of the compound as a fraction and multiply with the given mass;
For C;
= 88.06g
H; 
= 14.68g
O: 
= 117.41g
learn more:
Mass composition brainly.com/question/3018544
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Answer:
A. The sum of the voltages of the half-reactions is positive.
Explanation:
correct on a p e x
Colligative properties are properties that depends on ratio of the number of solute to the number of solvent . Colligative properties are essentially solvent properties that are changed by the presence of solute . The solute particles displaces some solvent molecules in the liquid phase and therefore reduce the concentration of solvent. So basically colligative properties are independent of the nature of the solute.
They are pretty much the cause and effect. The independent variable that is being changed in the experiment, so it is the cause. The dependant variable is the result of change the independant variable, so the effect.
