Na₂S(aq) + Cd(NO₃)₂(aq) = CdS(s) + 2NaNO₃(aq)
v=25.00 mL
c=0.0100 mmol/mL
M(Na₂S)=78.046 mg/mmol
n(Na₂S)=n{Cd(NO₃)₂}=cv
m(Na₂S)=M(Na₂S)n(Na₂S)=M(Na₂S)cv
m(Na₂S)=78.046*0.0100*25.00≈19.5 mg
Answer:

Explanation:
Given the moles, we are asked to find the mass of a sample.
We know that the molar mass of methanol is 32.0 grams per mole. We can use this number as a fraction or ratio.

Multiply by the given number of moles, which is 2.0

The moles of methanol will cancel each other out.

The denominator of 1 can be ignored.

Multiply.

There are 64 grams of methanol in the sample.
Explanation:
The observation of student was that thermometer reading changed from 27°C to 35°C which indicates that temperature of the beaker solution rose after reaction due to release of heat during reaction as a product.
Those chemical reactions which gives heat energy as a product into their surrounding are categorized as exothermic reactions. During the course of these reaction temperature of the surroundings also increased.
So, this means that reaction between silver nitrate and copper wire is an exothermic reaction.
Three ways that the student could speed up the reaction :
- By adding catalyst to the reaction.
- By decreasing the temperature.
- By increasing the concentration of silver nitarte solution.
The answer to this question would be: calcium ions to diffuse into the cell.
The presynaptic neuron would need to release neurotransmitter to the postsynaptic neuron. To do this, the action potential will cause calcium ion diffuse into the cell causing the vesicle with the neurotransmitter to migrate to the cell membrane and release its content.