FORENSIC SCIENCE HELP

Find the density of an object that has a mass of 5 kg and a volume of 50 cm3?

myrzilka [38]

Density = mass / volume

Mass = 5 kg

Volume = 50 cm³

d = 5 / 50

d = 0,1 kg/cm³

4 0

3 years ago

Which of the following describes a reaction that reaches equilibrium?

alexandr1967 [171]

Answer:The product and reactants reach a final, unchanging level.

8 0

3 years ago

How many grams of sulfuric acid is needed to neutralize 380 ml of solution with pH = 8.94

erma4kov [3.2K]

Answer : The mass of sulfuric acid needed is $16.23\times 10^{-5}g$ .

Solution : Given,

pH = 8.94

Volume of solution = 380 ml = $380\times 10^{-3}$ $(1ml=10^{-3}L)$

Molar mass of sulfuric acid = 98.079 g/mole

As we know,

$pH+pOH=14\\pOH=14-8.94=5.06$

$pOH=-log[OH^-]$

$5.06=-log[OH^-]$

$[OH^-]=0.00000871=8.71\times 10^{-6}mole/L$

Now we have to calculate the moles of $OH^-$ .

Formula used : $Moles=Concentration\times Volume$

$\text{ Moles of }[OH^-]=\text{ Concentration of }[OH^-]\times Volume\\\text{ Moles of }[OH^-]=(8.71\times 10^{-6}mole/L)\times (380\times 10^{-3}L)=3309.8\times 10^{-9}moles$

For neutralization, equal number of moles of $H^+$ ions will neutralize same number of $OH^-$ ions.

$\text{ Moles of }[OH^-]=\text{ Moles of }[H^+]=3309.8\times 10^{-9}moles$

As, $H_2SO_4\rightarrow 2H^++SO^{2-}_4$

From this reaction, we conclude that

2 moles of $H^+$ ion is given by the 1 mole of $H_2SO_4$

$3309.8\times 10^{-9}$ moles of $H^+$ ion is given by $\frac{3309.8\times 10^{-9}}{2}=1654.9\times 10^{-9}$ moles of $H_2SO_4$

Now we have to calculate the mass of sulfuric acid.

Mass of sulfuric acid = Moles of $H_2SO_4$ × Molar mass of sulfuric acid

Mass of sulfuric acid = $(1654.9\times 10^{-9}moles)\times (98.079g/mole)=162310.94\times 10^{-9}=16.23\times 10^{-5}g$

Therefore, the mass of sulfuric acid needed is $16.23\times 10^{-5}g$ .

3 0

3 years ago

A 2.83 g piece of zinc (density = 7.14 g/ml) is added to a graduated cylinder that contains 12.13 ml H2O. What will be the final

Maslowich

The final volume reading on the graduated cylinder is 12.52ml

Density = mass / volume

Volume = mass / density

Volume of zinc = 2.83/7.14

Volume of zinc = 0.3963

Initial volume = 12.13 ml

Total volume = initial volume+ volume of zinc

Total volume = 12.13 + 0.3963

Total volume = 12.5263 = 12.52 ml

To know more about volume to go the given link :

brainly.com/question/11510153

3 0

2 years ago

___CH4 + ___O2 → ___CO2 + ___H2O When you burn natural gas in the laboratory, methane burns. What numbers fill in the blanks to

Hitman42 [59]

Answer:

The coefficient are 1,2,1,2 ( option B is correct)

Explanation:

Step 1: Data given

Methane = CH4

Burning methane = CH4 + O2

Step 2: The unbalanced equation

CH4(g) + O2(g) → CO2(g) + H2O(g)

Step 3: Balancing the equation

CH4(g) + O2(g) → CO2(g) + H2O(g)

On the left side we have 4x H (in CH4), on the right side we have 2x H (in H2O). To balance the amount of H, on both sides, we have to multiply H2O (on the right side by 2).

CH4(g) + O2(g) → CO2(g) + 2H2O(g)

On the left side we have 2x O (in O2), on the right side we have 4x O (2x in CO2 and 2x in 2H2O). To balance the amount of O on both sides, we have to multiply O2 (on the left side by 2).

CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)

The coefficient are 1,2,1,2 ( option B is correct)

3 0

3 years ago