URGENT!!!! HNO3 and H2CO3 are examples of A.acids<br> b.bases<br> c.salts<br> neutral compounds.

Which of these statements best explains why chemistry is reliable?

marissa [1.9K]

Gives the same result when an experiment is repeated.

4 0

4 years ago

A 3.31-g sample of lead nitrate, pb(no3)2, molar mass = 331 g/mol, is heated in an evacuated cylinder with a volume of 2.11 l. t

bearhunter [10]

The equation in this problem is: 2Pb(NO3)2(s) --> 2PbO(s) + 4NO2(g) + O2(g)

And the question is what the pressure in the cylinder is after decomposition and cooling to a temperature of 300 K.

Solution:

Moles of Pb (NO3)2 = 3.31/331 = 0.0100

2 moles of Pb (NO3)2 will decay to mold 4 moles of NO2 and 1 mole of O2. So 0.0100 moles of Pb (NO3)2 will form 0.02 moles of NO2 and 0.00500 moles of O2

Then use the formula: PV = nRT.

P = (0.02 + 0.005) * 0.082 * 300 / 1.62

= 0.380 atm

7 0

3 years ago

Which of the following acts as a catalyst in catalytic converters?

yaroslaw [1]

Answer: B. Metal

Explanation: The catalyst used in the converter is mostly a precious metal such as platinum, palladium and rhodium Hope This Helped (=^･-･^=)

4 0

3 years ago

Read 2 more answers

Explain why the equation ( x - 4 ) ^2 - 28 =8 has two solutions. Then solve the equation to find the solutions. Show your work.

algol13

Taking into account the discriminant and quadratic formula:

As Δ> 0 the function has two real roots or solutions.
The solutions are x1= 10 and x2= -2.

<h3 />

Zeros or solutions of a function

The points where a polynomial function crosses the axis of the independent term (x) represent the so-called zeros of the function.

That is, the zeros represent the roots of the polynomial equation that is obtained by making f(x)=0.

In summary, the roots or zeros of the quadratic function are those values of x for which the expression is equal to 0. Graphically, the roots correspond to the abscissa of the points where the parabola intersects the x-axis.

<h3>Discriminant</h3>

The function f(x) = ax² + bx + c

with a, b, c real numbers and a ≠ 0, is a function quadratic expressed in its polynomial form (It is so called because the function is expressed by a polynomial).

The following expression is called discriminant:

Δ= b²- 4×a×c

The discriminant determines the amount of roots or solutions of the function.

Then:

If Δ <0 the function has no real roots and its graph does not intersect the x-axis.
If Δ> 0 the function has two real roots and its graph intersects the x-axis at two points.
If Δ = 0 the function has a real root and its graph intersects the x-axis at a single point that coincides with its vertex. In this case the function is said to have a double root.

<h3 /><h3>Amount of solutions of function (x - 4)² - 28 =8</h3>

The function (x - 4)² - 28 =8 can be expressed as:

(x - 4)² - 28 -8= 0

(x - 4)² - 36= 0

x²- 8x + 16 - 36= 0

x²- 8x - 20= 0

Being:

a= 1
b= -8
c= -20

the amount of solutions are calculated as:

Δ= (-8)²- 4×1×(-20)

Δ= 144

As Δ> 0 the function has two real roots or solutions and its graph intersects the x-axis at two points.

<h3>Solutions of a cuadratic function</h3>

In a quadratic function that has the form:

f(x)= ax² + bx + c

the zeros or solutions are calculated by:

$x1,x2=\frac{-b+-\sqrt{b^{2}-4ac } }{2a}$

<h3>Solutions of function (x - 4)² - 28 =8</h3>

The function (x - 4)² - 28 =8 can be expressed as x²- 8x - 20= 0

Being:

a= 1
b= -8
c= -20

the solutions of the function are calculated as:

$x1=\frac{-(-8)+\sqrt{(-8)^{2}-4x1x(-20) } }{2x1}$

$x1=\frac{-(-8)+\sqrt{144 } }{2x1}$

$x1=\frac{8+\sqrt{144 } }{2}$

$x1=\frac{8+12 }{2}$

$x1=\frac{20}{2}$

x1= 10

and

$x2=\frac{-(-8)-\sqrt{(-8)^{2}-4x1x(-20) } }{2x1}$

$x2=\frac{-(-8)-\sqrt{144 } }{2x1}$

$x2=\frac{8-\sqrt{144 } }{2}$

$x2=\frac{8-12}{2}$

$x2=\frac{-4}{2}$

x1= -2

Finally, the quadratic function (x - 4)² - 28 =8 has two solutions and the solutions are x1= 10 and x2= -2.

Learn more about the zeros of a quadratic function:

<u>brainly.com/question/14477557</u>

<u>brainly.com/question/842305</u>

<u>brainly.com/question/14477557</u>

7 0

3 years ago

How is all the “stuff” around us matter is because it is made up of atoms?

Viefleur [7K]

Answer:

Matter is the Stuff Around You

Matter is everything around you. Atoms and compounds are all made of very small parts of matter. ... Matter is defined as anything that has mass and takes up space (it has volume).

Explanation:

hope it was helpful

6 0

3 years ago

URGENT!!!! HNO3 and H2CO3 are examples of A.acids b.bases c.salts neutral compounds.