How much energy is lost through carrying out life functions?

How many moles of KBr are present in 500 ml of a 0.8 M KBr solution?

faltersainse [42]

Answer:

2) 0.4 mol

Explanation:

Step 1: Given data

Volume of the solution (V): 500 mL

Molar concentration of the solution (M): 0.8 M = 0.8 mol/L

Step 2: Convert "V" to L

We will use the conversion factor 1 L = 1000 mL.

500 mL × 1 L/1000 mL = 0.500 L

Step 3: Calculate the moles of KBr (solute)

The molarity is the quotient between the moles of solute (n) and the liters of solution.

M = n/V

n = M × V

n = 0.8 mol/L × 0.500 L = 0.4 mol

4 0

3 years ago

Burning 12.00 g of an oxoacid produces 17.95 g of carbon dioxide and 4.87 g of water. Consider that 0.25

Veseljchak [2.6K]

Answer: The molecular formula will be $C_6H_6O_6$

Explanation:

Mass of $CO_2$ = 17.95 g

Mass of $H_2O$ = 4.87 g

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 17.95 g of carbon dioxide, = $\frac{12}{44}\times 17.95=4.89g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 4.87 g of water, = $\frac{2}{18}\times 4.87=0.541g$ of hydrogen will be contained.

Mass of oxygen in the compound = (12.00) - (4.89+0.541) = 6.57 g

Mass of C = 4.89 g

Mass of H = 0.541 g

Mass of O = 6.57 g

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{4.89g}{12g/mole}=0.407moles$

Moles of H= $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.541g}{1g/mole}=0.541moles$

Moles of O= $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{6.57g}{16g/mole}=0.410moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{0.407}{0.407}=1$

For H = $\frac{0.541}{0.407}=1$

For O = $\frac{0.410}{0.407}=1$

The ratio of C : H : O = 1: 1 : 1

Hence the empirical formula is $CHO$ .

Hence the empirical formula is $CHO$

The empirical weight of $CHO$ = 1(12)+1(1)+1(16)= 29 g.

If 0.25 moles has mass of 44.0 g

Thus 1 mole has mass of = $\frac{44.0}{0.25}\times 1=176g$

Thus molecular mass is 176 g

Now we have to calculate the molecular formula.

$n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{176g}{29g}=6$

The molecular formula will be= $6\times CHO=C_6H_6O_6$

5 0

3 years ago

How many atoms are in 3 moles of nitrogen

olga nikolaevna [1]

Answer:1 mol of Mg(NO3)2 contains 6.022*10^23 molecules

3 mol Mg(NO3)2 contains 3*6.022*10^23 = 1.81*10^24 molecules

Each Mg(NO3)2 molecule contains 2 N atoms

Number of N atoms = 2*1.81*10^24 = 3.62*10^24 N atoms.

8 0

3 years ago

When magnesium loses it's valence electrons, it has the atomic structure of what element?

Arte-miy333 [17]

As far as I can tell the best answer for this would be (A) Neon. However, I would argue that this is at the very least a misleading question. Atoms are less identified by their electrons than their protons (which is represented always by its atomic number). Although atoms can gain or lose electrons, the protons would never change (and remain the same element). Personally, I would have written the question as, "When Magnesium loses its valence electrons, its new number of electrons would most closely resemble _____"

4 0

3 years ago

Can anyone do my Ap environmental science package I will pay you

Phoenix [80]

Answer:

i have taken environmental science so i can help

4 0

3 years ago