All categories

2 years ago

What is the magnitude of the vector described below?

Chemistry

2 answers:

ElenaW [278]2 years ago

7 0

There are two types of 'quantities' namely: scalar and vector

A 'vector' is a quantity that has both magnitude and direction whereas a 'scalar' has only magnitude.

Magnitude is a measure or the size of the quantity or object.

In the given example of the vector: '75 mph to the north'

Magnitude is the number 75 mph

Direction is north

Ans C)

Tom [10]2 years ago

3 0

Answer:

its 75 mph because 75 is the quantity

Explanation:

You might be interested in

Daphne is a pilot for a package delivery service. As her plane takes off and travels away from the Earth’s surface, its gravitat

Lubov Fominskaja [6]

Answer:

its height relative to some reference point, its mass, and the strength of the gravitational field

Explanation:

Gravitational energy is the potential energy associated with gravitational force, such as elevating objects against the Earth’s gravity. The potential energy due to elevated positions is called gravitational potential energy.

The factors that affect an object’s gravitational potential energy are the following; its height relative to some reference point, its mass, and the strength of the gravitational field it is in. For instance, consider a wallet lying on a table, it has less gravitational potential energy than the same wallet lying on top of a taller cupboard, and yet lesser gravitational potential energy than a heavier wallet lying on the same table.

If an object lies at a certain height above the Moon’s surface, it has less gravitational potential energy than the same object lying at the same height above the Earth’s surface because the Moon’s gravitational force is weaker.

5 0

2 years ago

Which formula represents the compound commonly known as phosphine PH PH2 PH3 PH4

AveGali [126]

The answer is C). PH3

4 0

2 years ago

Read 2 more answers

How many grams of Cr can be produced by the reaction of 44.1 g of Cr2O3 with 35.0 g of Al according to the following chemical eq

allsm [11]

Answer:

30.17 grams of Cr can be produced by the reaction of 44.1 g of Cr₂O₃ with 35.0 g of Al.

19.33 grams of the excess react will remain once the reaction goes to completion.

Explanation:

You know:

2 Al + Cr₂O₃ → Al₂O₃ + 2 Cr

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of the compounds participating in the reaction react and are produced:

Al: 2 moles
Cr₂O₃: 1 mole
Al₂O₃: 1 mole
Cr: 2 moles

Being:

Al: 27 g/mole
Cr: 52 g/mole
O: 16 g/mole

the molar mass of the compounds participating in the reaction is:

Al: 27 g/mole
Cr₂O₃: 2*52 g/mole + 3 *16 g/mole= 152 g/mole
Al₂O₃: 2*27 g/mole + 3 *16 g/mole= 102 g/mole
Cr: 52 g/mole

Then, by stoichiometry of the reaction, the amounts of reagents and products that participate in the reaction are:

Al: 2 moles* 27 g/mole= 54 g
Cr₂O₃: 1 mole* 152 g/mole= 152 g
Al₂O₃: 1 mole* 102 g/mole= 102 g
Cr: 2moles*52 g/mole= 104 g

First, you must determine the limiting reagent. The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

Then, for this you must apply the following rule of three: if 54 grams of Al react with 152 grams of Cr₂O₃ by stoichiometry of the reaction, 35 grams of Al with how much mass of Cr₂O₃ will react?

$mass of Cr_{2} O_{3} =\frac{35 grams of Al*152 gramsof Cr_{2} O_{3}}{54 grams of Al}$

mass of Cr₂O₃= 98.52 grams

But 98.52 grams of Cr₂O₃ are not available, 44.1 grams are available. Since you have less moles than you need to react with 35 grams of Al, the compound Cr₂O₃ will be the limiting reagent.

To determine the amount of Cr that can be produced, you use the amount of limiting reagent available and apply the following rule of three: if by stoichiometry 152 grams of Cr₂O₃ produce 104 grams of Cr, 44.1 grams of Cr₂O₃ how much mass of Cr does it produce?

$mass of Cr =\frac{104 grams of Cr*44.1 grams of Cr_{2} O_{3}}{152 grams of Cr_{2} O_{3}}$

mass of Cr= 30.17 grams

30.17 grams of Cr can be produced by the reaction of 44.1 g of Cr₂O₃ with 35.0 g of Al.

As Al is the excess reagent, you must first calculate the amount of mass that reacts with 44.1 grams of Cr₂O₃ using the following rule of three: if 152 grams of Cr₂O₃ react with 54 grams of Al, 44.1 grams of Cr₂O₃ with how much mass of Al reaction to?

$mass of Al =\frac{54 grams of Al*44.1 gramsnof Cr_{2} O_{3}}{152 gramsnof Cr_{2} O_{3}l}$

mass of Al=15.67 grams

With 35 grams being the amount of Al available, the amount of Al that will remain in the reaction after all the limiting reagent reacts and the reaction is complete is calculated by:

mass of excess= 35 grams - 15.67 grams= 19.33 grams

19.33 grams of the excess react will remain once the reaction goes to completion.

6 0

2 years ago

Even though we are well into the course Dumbledore notices some of the students are still having trouble with significant figure

Sphinxa [80]

Answer:

B) 2

Explanation:

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

The rule apply for the multiplication and division is :

The least number of significant figures in any number of the problem determines the number of significant figures in the answer.

The rule apply for the addition and subtraction is :

The least precise number present after the decimal point determines the number of significant figures in the answer.

(3.478-2.31) = 1.168 ≅ 1.17 (Rounded to least decimal digit)

(4.428-3.56) = 0.868 ≅ 0.87 (Rounded to least decimal digit)

So,

1.17 * 0.87 = 1.0 (Rounded to least significant)

Answer - two significant digits

5 0

2 years ago

David has two containers of two different gases at the same temperature and pressure. David could assume all of following EXCEPT

pychu [463]

Answer:

David could not assume that:

 when the pressure is decreased, the temperature of both containers will increase (option D).

Explanation:

Since this question has only one answer, you must assume that both containers are identical, i.e. have the same volume.

Using the ideal gas equation pV = nRT you can conclude that pressure and temperature are directly related, i.e. if the pressure is decreased, the temperature will decrease proportionally, which is opposite to the assumption that when the pressure is decreased, the temperature of both containers will increase.

On the other hand, from the same equation, you can tell the relationship between the other variables and conclude that the other choices are valid assumptions:

A. when the temperature is increased, the volume of both containers will increase:

Correct: pV = nRT shows that volume and temperature are directly related: when T increase, V increase)

B. when the pressure is increased, the volume of both containers will decrease

Correct: pV = nRT shows that p and V and inversely related, so when p is incrased, V will decrease.

C. both containers contain the same number of gas particles

Correct, only if the two containers are identical: since the two containers of the two different gases are at the same temperature and pressure, the equation pV = nRT, shows that if the volumes are equal the number of particles are the same.

3 0

2 years ago