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IgorLugansk [536]
3 years ago
14

I am confused, please help

Chemistry
1 answer:
lesya [120]3 years ago
8 0
A candle will change mechanically by making the candle smaller. It will change chemically by melting the wax of the candle.
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50.g of NaNO3 was dissolved in 1250 mL of water. what is the molality of the solution? [ Molar mass of NaNO3 = 85 g/mol
Viefleur [7K]

Answer:

Approximately 0.47\; \rm mol \cdot L^{-1} (note that 1\; \rm M = 1 \; \rm mol \cdot L^{-1}.)

Explanation:

The molarity of a solution gives the number of moles of solute in each unit volume of the solution. In this \rm NaNO_3 solution in water,

Let n be the number of moles of the solute in the whole solution. Let V represent the volume of that solution. The formula for the molarity c of that solution is:

\displaystyle c = \frac{n}{V}.

In this question, the volume of the solution is known to be 1250\; \rm mL. That's 1.250\; \rm L in standard units. What needs to be found is n, the number of moles of \rm NaNO_3 in that solution.

The molar mass (formula mass) of a compound gives the mass of each mole of units of this compound. For example, the molar mass of \rm NaNO_3 is 85\; \rm g \cdot mol^{-1} means that the mass of one mole of

\displaystyle n = \frac{m}{M}.

For this question,

\begin{aligned}&n\left(\mathrm{NaNO_3}\right) \\ &= \frac{m\left(\mathrm{NaNO_3}\right)}{M\left(\mathrm{NaNO_3}\right)}\\&= \frac{50\; \rm g}{85\; \rm g \cdot mol^{-1}} \\& \approx 0.588235\; \rm mol\end{aligned}.

Calculate the molarity of this solution:

\begin{aligned}c &= \frac{n}{V} \\&= \frac{0.588235\; \rm mol}{1.250\; \rm L} \\&\approx 0.47\;\rm mol \cdot L^{-1}\end{aligned}.

Note that 1\; \rm mol \cdot L^{-1} (one mole per liter solution) is the same as 1\; \rm M.

8 0
3 years ago
A type of marble has a density of 2.5 grams/marble. A box filled with marbles has a total mass of 300 grams determine the number
Maurinko [17]

Answer:

100

Explanation:

Step 1: Subtract 50 by 300 to find the total mass of the marbles

300 - 50 = 250

Not hard, right?

Step 2: Divide 250 by 2.5

250 ÷ 2.5 = 100

And... 100 is your answer :)

Hope this helps :)

-jp524

4 0
3 years ago
2Fe2O3 + 3C → 4Fe + CO2 <br><br> IS this a balanced equation?
Dima020 [189]

Answer:

No

Explanation:

In the left side of the reaction, there are 6O and 3C but on the right side, there are only 1C and 2O

6 0
3 years ago
How many moles are in a sample of 1.52 x 1024 atoms of mercury (Hg)?
OLEGan [10]

The answer is:

2.5 moles

The explanation:

when avogadro's number = 6.02 * 10^23

and when 1 mole of the sample will give → 6.02*10^23 atoms

So,        ??? mole of the sample will give→ 1.52 x 10^24 atoms

∴ number of moles = (1.52 X 10^24) * 1 mole / (6.02X10^23)

                                = 2.5 moles

8 0
3 years ago
If dr. john sutherland is correct, which of the following was necessary for inert carbon atoms to become part of the chemistry o
arlik [135]
It seems that you have missed the necessary options for us to answer this question so I had to look for it. But anyway, here is the answer. If Dr. John Sutherland is correct, the one that was necessary <span> for inert carbon atoms to become part of the chemistry of earth is CYANIDE. Hope this helps.</span>
8 0
4 years ago
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