What are three moving parts of electricity

How many water molecules does it contain? The density of water is 1.0 g/cm3.

max2010maxim [7]

Complete question is;

A drop of water has a volume of approximately 7 × 10⁻² ml. How many water molecules does it contain? The density of water is 1.0 g/cm³.

This question will require us to first find the number of moles and then use avogadro's number to get the number of water molecules.

Number of water molecules = 2.34 × 10²¹ molecules

We are given;

Volume of water; V = 7 × 10⁻² ml

Density of water; ρ = 1 g/cm³ = 1 g/ml

Formula for mass is; m = ρV

m = 1 × 7 × 10⁻²

m = 7 × 10⁻² g

from online calculation, molar mass of water = 18.01 g/mol

Number of moles(n) = mass/molar mass

Thus;

n = (7 × 10⁻²)/18.01

n = 3.887 × 10⁻³ mol

from avogadro's number, we know that;

1 mol = 6.022 × 10²³ molecules

Thus,3.887 × 10⁻³ mol will give; 6.022 × 10²³ × 3.887 × 10⁻³ = 2.34 × 10²¹ molecules

Read more at; brainly.in/question/17990661

6 0

2 years ago

A potassium bromide solution is 8.30% potassium bromide by mass and its density is 1.03 g/ml. what mass of potassium bromide is

pshichka [43]

Answer: The mass of potassium bromide present in 41.2 mL of solution will be 3.522 grams.

Explanation:

We are given that KBr is present in 8.3% KBr solution, which means that 8.3 grams of potassium bromide is present in 100 gram of the solution.

To calculate the volume of KBr, we use the formula:

$Density=\frac{Mass}{Volume}$

Mass of the solution = 100 grams

Density of KBr solution = 1.03g/mL

Volume of the solution = ? mL

Putting values in above equation, we get:

$1.03g/mL=\frac{100g}{Volume}\\\\Volume=97.08mL$

Now, to calculate the mass of KBr in 41.2mL of the solution, we use unitary method.

In 97.08 mL of solution, mass of KBr present is 8.3 grams.

So, 41.2 mL of solution will contain = $\frac{8.3g}{97.08mL}\times 41.2mL=3.522g$ of KBr.

Hence, the mass of potassium bromide present in 41.2 mL of solution will be 3.522 grams.

7 0

2 years ago

Match the chemical with the statement that best describes the observed change in the rate of the reaction when the concentration

maria [59]

Answer:

Explanation:

When the amount of H2O2 is doubled while KI is kept constant, the rate of reaction doubles.

When the amount of KI is doubled and the amount of H2O2 is halved, the rate stays nearly constant.

2H2O2 (aq) → O2(g) + 2H2O (l) ------------- first order kinetics reaction.

Catalysts are KI, FeCl3 only, KCl is not a catalyst. Order: KI < MnO2 < Pb < FeCl3.

H2O2 + I– -> IO– + H2O (Step 1)

H2O2 + IO– -> I– + H2O + O2 (Step 2)

It can be seen that the iodine ion (provided by the KI solution) is a product as well as a reactant.

02(g)2Fe? (aq) + 2 H(a) 2 H 2 Fe3 (aq) H2O2(aq) + 2 Fe,Taq) H02(aq) 2 Fe (aq) 2 H (aq)

8 0

2 years ago

A graduated cylinder is filled to the 40.00-mL mark with a mineral oil. The masses of the cylinder before and after the addition

castortr0y [4]

Answer:

Firstly, Let's experiment this !

Experiment 1 :

159.446g - 124.966g = 34.48g

34.48g = The mass of Mineral oil.

The density of the mineral oil = M/V = 34.48g/40mL = 0.862g/cm³.

Experiment 2 :

124.966 + 18.173 = 143.139 = The mass of solid + cylinder.

124.966 + 50.952 = 175.918 = The mass of solid + cylinder + Mineral water.

175.918 - 143.139 = 32.779 = The mass of added mineral oil.

Explanation:

Now we have to find the volume of the added mineral oil using the density from experiment 1.

V = 32.779g/0.862g/cm³ = 38.02668213mL

Since we found the volume of the solid, we then have to subtract the added mineral oil volume from the total volume from experiment 1.

Volume of solid = 40-38.02668213 = 1.97331787mL

Density of solid = 18.713g/1.97331787mL = 9.483013499g/cm^3

1.97331787 = (4/3)(3.14)r³

1.97331787*(3/4)(3.14) = .4713338861

.4713338861 = r ³

r = 0.7782328425158433

r = 0.78

Now that's our final answer ! r = 0.78

5 0

2 years ago

Aluminum and copper are examples of what

agasfer [191]

They are examples of elements.

3 0

2 years ago

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