Which of the following metal atoms only form one type of positive change ? K Cu Fe Mg

An inverted pyramid is being filled with water at a constant rate of 45 cubic centimeters per second. The pyramid, at the top, h

vaieri [72.5K]

Answer:

13.20 cm/s is the rate at which the water level is rising when the water level is 4 cm.

Explanation:

Length of the base = l

Width of the base = w

Height of the pyramid = h

Volume of the pyramid = $V=\frac{1}{3}lwh$

We have:

Rate at which water is filled in cube = $\frac{dV}{dt}= 45 cm^3/s$

Square based pyramid:

l = 6 cm, w = 6 cm, h = 13 cm

Volume of the square based pyramid = V

$V=\frac{1}{3}\times l^2\times h$

$\frac{l}{h}=\frac{6}{13}$

$l=\frac{6h}{13}$

$V=\frac{1}{3}\times (\frac{6h}{13})^2\times h$

$V=\frac{12}{169}h^3$

Differentiating V with respect to dt:

$\frac{dV}{dt}=\frac{d(\frac{12}{169}h^3)}{dt}$

$\frac{dV}{dt}=3\times \frac{12}{169}h^2\times \frac{dh}{dt}$

$45 cm^3/s=3\times \frac{12}{169}h^2\times \frac{dh}{dt}$

$\frac{dh}{dt}=\frac{45 cm^3/s\times 169}{3\times 12\times h^2}$

Putting, h = 4 cm

$\frac{dh}{dt}=\frac{45 cm^3/s\times 169}{3\times 12\times (4 cm)^2}$

$=13.20 cm/s$

13.20 cm/s is the rate at which the water level is rising when the water level is 4 cm.

3 0

3 years ago

The mass percentage of hydrochloric acid within a solution is 28.00%28.00% . Given that the density of this solution is 1.1411.1

sashaice [31]

Answer:

8.76M

Explanation:

Given that

Mass from the density = 1141g

According to the given situation the computation of molarity of the solution is shown below:-

we will took HCL solution which is 1000mL

HCl = 28% by mass

So,

Mass of HCl in 1-litre solution is

$= \frac{28}{100} \times 1141$

Which gives the result of molar mass HCI is

= 319.48g /mol

Now,

Molarity is

$= \frac{319.48}{36.45}$

Which gives results of molarity is

= 8.76M

8 0

3 years ago

Please help I’ve been stuck for 2 hours

Vinvika [58]

find the answer in the attached image. please mark as brainliest if it is helpful.

7 0

3 years ago

A sample of pure water contains

prohojiy [21]

The answer is c because it is helpful to understand the balance between these two ions. An aqueous solution is a solution in which water is the solvent. Water molecules (H2O) are polar, meaning that they have a negative end (the oxygen) and a positive end (the hydrogens). When there is a reaction in an aqueous solution, the water molecules have the ability to attract and temporarily hold a donated proton (H+). This creates the hydronium ion (H3O+).

8 0

3 years ago

Small quantities of oxygen can be prepared in the laboratory by heating potassium chlorate, KClO3(s).

pychu [463]

Answer:

26.110 grams of O2 produced.

Explanation:

Calculate the amount of moles in KClO3 by dividing the amount of grams given by the atomic weight of the substance.

To get the atomic weight: K = 39.098, Cl = 35.45, O = 15.999, and there are 3 molecules of Oxygen, so multiply 15.999 by three.

39.098 + 35.45 + (15.999 * 3) = 122.548.

66.7g / 122.548 atomic mass = 0.544 moles.

The ratio of moles of KClO3 to moles of O2 is 2 to 3.

$\frac{2}{3}$ = $\frac{0.544}{y}$

Cross multiply to get 1.632 = 2y. Y = 0.816, meaning 0.816 moles of O2 will be produced.

Convert this into grams by multiplying by the atomic weight of O2 (15.999 * 2 = 31.998).

0.816 * 31.998 = 26.110 grams of O2 produced.

3 0

3 years ago