7.91 g/ml is the density of the iron piece of 28.5 gms.
Explanation:
The density of a substance is defined as the volume it occupies. It tells the matter present in a substance.
The density is mass per unit volume and is denoted by p.
The formula for density is given by:
density (p) = 
Data given is :
mass= 28.5 grams
V1 = 45.5 ml
V2= 49.1 ml
The initial volume of water was 45.5 ml, when iron piece of 28.5 grams was added the final volume was 49.1 ml.
Putting the values in the equation of density
p = 
p = 7.91 g/ml
Since iron is a dense material it will occupy less volume
Molarity is expressed as the number of moles of solute per volume of the solution. For example, we are given a solution of 2M NaOH this describes a solution that has 2 moles of NaOH per 1 L volume of the solution. To calculate the moles of NaCl in 1.0 M of solution, we simply multiply the volume given of the solution.
moles NaCl = 1.0 M (0.100 L ) = 0.10 mol NaCl --------> OPTION B
Answer:
6.43 moles of NF₃.
Explanation:
The balanced equation for the reaction is given below:
N₂ + 3F₂ —> 2NF₃
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of NF₃.
Finally, we shall determine the number of mole of nitrogen trifluoride (NF₃) produced by the reaction of 9.65 moles of Fluorine gas (F₂). This can be obtained as follow:
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of NF₃.
Therefore, 9.65 moles of F₂ will react to to produce = (9.65 × 2)/3 = 6.43 moles of NF₃.
Thus, 6.43 moles of NF₃ were obtained from the reaction.
Answer:

Explanation:
Hello,
In this case, considering the density and mass of both water and heptane we first compute the volume of each one:

Now, the total volume is:

Which is equal to:

Then, by knowing that the volume of a cylinder is πr²h or π(D/2)²h, we solve for the height as follows:

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