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3 years ago

Describe the process used to measure out a specific mass of a solid

1 answer:

7 0

Although the process varies slightly from one material to another, the general process is as follows:

1) Choose an appropriate container for the solid. This may be a petri dish or a beaker in which you want to prepare the solution of the solid or any other lab equipment.

2) Place the container on a mass balance, then turn the balance on. The mass balance will automatically zero-out the mass of the container, so that any mass that you add on the container will be the mass of the solid. Alternatively, you may first measure the mass of the empty container alone.

3) Add the solid using a lab spatula. The solid should be added more slowly when the reading on the scale comes close to the desired value.

4) Remove the container from the mass balance after the desired amount of solid has been added.

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ΔH for the formation of CuCl2 from its elements is -220.1 kJ/mol. How many kJ are associated with the formation of 0.30 mole of

otez555 [7]

0.3 * - 220.1 = - 66.03kJ

3 0

3 years ago

Read 2 more answers

A compound with the empirical formula CH 2 O has a formula mass of 180 g/mol. What is its molecular formula

olga nikolaevna [1]

Empirical formula mass

12+2(1)+16
28+2
30g/mol

Molecular fornula mass:-180g/mol

n=Molecular formula mass/Empirical formula mass
m=180/30
n=6

Molecular formula:-

n×Empirical formula
6(CH_2O
C_6H_12 O_6

5 0

2 years ago

which solution below would be considered the most acidic?a. 2.9 x 10-4 m hclb. 4.5 x 10-5 m hno3c. 1.0 x 10-7 m nacld. 1.5 x 10-

kkurt [141]

Answer:

a. 2,9x10⁻⁴ M HCl

Explanation:

A solution is considered acidic when its concentration of H⁺ is higher than 1x10⁻⁷. The higher concentration of H⁺ will be the most acidic solution.

a. 2,9x10⁻⁴ M HCl. In water, this solution dissolves as H⁺ and Cl⁻. That means concentration of H⁺ is 2,9x10⁻⁴ M.

b. 4,5x10⁻⁵M HNO₃. In the same way, concentration of H⁺ is 4,5x10⁻⁵M.

c. 1,0x10⁻⁷M NaCl. As this solution doesn't produce H⁺, the solution is not acidic

d. 1,5x10⁻²M KOH. This solution produce OH⁻. That means the solution is basic nor acidic.

Thus, the solution considered the most acidic is a. 2,9x10⁻⁴ M HCl, because has the higher concentration of H⁺.

I hope it helps!

7 0

3 years ago

A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by O 3 ( g ) + NO ( g )

Aleksandr [31]

Answer:

(a) 7.11x10⁻⁴ M/s

(b) 2.56 mol.L⁻¹.h⁻¹

Explanation:

(a) The reaction is:

O₃(g) + NO(g) → O₂(g) + NO₂(g) (1)

The reaction rate of equation (1) is given by:

$rate = k*[O_{3}][NO]$ (2)

k: is the rate constant of reaction = 3.91x10⁶ M⁻¹.s⁻¹

[O₃]₀ = 2.35x10⁻⁶ M

[NO]₀ = 7.74x10⁻⁵ M

Hence, to find the inital reacion rate we will use equation (2):

$rate = k*[O_{3}]_{0}[NO]_{0} = 3.91 \cdot 10^{6} M^{-1}s^{-1}*2.35\cdot 10^{-6} M*7.74 \cdot 10^{-5} M = 7.11 \cdot 10^{-4} M/s$

Therefore, the inital reaction rate is 7.11x10⁻⁴ M/s

(b) The number of moles of NO₂(g) produced per hour per liter of air is:

t = 1 h

V = 1 L

$\frac{\Delta[NO_{2}]}{\Delta t} = rate$

$\frac{\Delta[NO_{2}]}{\Delta t} = 7.11 \cdot 10^{-4} M/s*\frac{3600 s}{1 h} = 2.56 mol.L^{-1}.h{-1}$

Hence, the number of moles of NO₂(g) produced per hour per liter of air is 2.56 mol.L⁻¹.h⁻¹

I hope it helps you!

5 0

3 years ago

Which energy source uses a fuel that produces a large amount of energy from a small amount of fuel

Vitek1552 [10]

That would be either, nuclear power or wind power, depending on what the teacher is looking for...

8 0

3 years ago