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2 years ago

Which of these reactions can be classified as double replacement reactions?

1 answer:

4 0

1) Zn + 2 HCl = ZnCl2 + H2 ( single replacement )

2) 2 NaCl + F2 = 2 NaF + Cl2 ( single replacement )

3) 2 AlBr3 + 3 K2SO4 = 6 KBr + Al2(SO4)3 ( double replacement )

4) 2 K + MgBr2 = 2 KBr + Mg ( single replacement )

Answer 3

hope this helps!

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Most elements are O non metals O metalloids O metals O gases

Aliun [14]

Metallioids
Explain

4 0

2 years ago

Please help me

Wittaler [7]

Answer:

pH = 6.999

The solution is acidic.

Explanation:

HBr is a strong acid, a very strong one.

In water, this acid is totally dissociated.

HBr + H₂O → H₃O⁺ + Br⁻

We can think pH, as - log 7.75×10⁻¹² but this is 11.1

acid pH can't never be higher than 7.

We apply the charge balance:

[H⁺] = [Br⁻] + [OH⁻]

All the protons come from the bromide and the OH⁻ that come from water.

We can also think [OH⁻] = Kw / [H⁺] so:

[H⁺] = [Br⁻] + Kw / [H⁺]

Now, our unknown is [H⁺]

[H⁺] = 7.75×10⁻¹² + 1×10⁻¹⁴ / [H⁺]

[H⁺] = (7.75×10⁻¹² [H⁺] + 1×10⁻¹⁴) / [H⁺]

This is quadratic equation: [H⁺]² - 7.75×10⁻¹² [H⁺] - 1×10⁻¹⁴

a = 1 ; b = - 7.75×10⁻¹² ; c = -1×10⁻¹⁴

(-b +- √(b² - 4ac) / (2a)

[H⁺] = 1.000038751×10⁻⁷

- log [H⁺] = pH → 6.999

A very strong acid as HBr, in this case, it is so diluted that its pH is almost neutral.

8 0

2 years ago

If a 125 gms of radioactive element has a half life of 60 min how many half lives will it go through to become 3.90625 gms

Sonja [21]

Answer:

Explanation:

Let the number of half lives be x

Solve this equation to find the value of x:

125*(1/2)ˣ = 3.90625
(0.5)ˣ = 3.90625 / 125
(0.5)ˣ = 0.03125
log (0.5)ˣ = log 0.03125
x = log 0.03125 / log 0.5
x = 5

4 0

2 years ago

How to answer this ?

nadezda [96]

You multiply (4×10)by*

6 0

2 years ago

A sample of gas is observed to effuse through a pourous barrier in 4.98 minutes. Under the same conditions, the same number of m

kogti [31]

Answer:

The molar mass of the unknown gas is $\mathbf{ 51.865 \ g/mol}$

Explanation:

Let assume that the gas is O2 gas

O2 gas is to effuse through a porous barrier in time t₁ = 4.98 minutes.

Under the same conditions;

the same number of moles of an unknown gas requires time t₂ = 6.34 minutes to effuse through the same barrier.

From Graham's Law of Diffusion;

Graham's Law of Diffusion states that, at a constant temperature and pressure; the rate of diffusion of a gas is inversely proportional to the square root of its density.

i.e

$R \ \alpha \ \dfrac{1}{\sqrt{d}}$