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3 years ago

Between a substance and a mixture. give two examples of each

2 answers:

8 0

A substance has a uniform composition. A mixture is a mix of elements not combined chemically.

Example of substance:- Gold

Example of mixture:- Salad

riadik2000 [5.3K]3 years ago

7 0

A substance whether it is an element or a compound must have homogenous properties whereas a mixture is a combination of pure substances that have no definite composition. It may be either a homogenous or heterogeneous. Examples of substances are liquid water and carbon dioxide. If you take a drop of water and put under the microscope, you will see that it the molecules of water are the same in every curve. For mixtures, air and sand. Air has a lot of components in it, it has oxygen, nitrogen, argon, etc.

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The mass of a sample of sodium bicarbonate is 2. 1 kilograms (kg). There are 1,000 grams (g) in 1 kg, and 1 Times. 109 nanograms

slega [8]

2.1 kg of sodium bicarbonate is equal to the 2.1 x 10¹² ng of sample. Option D is correct.

Mass is the quantity of the substance in the body or object. The SI unit of mass is Kilogram.

There are other units of measure,

Milligram: 1 g is equal to the $\bold {10^3 \ mg}$

Micro-gram: 1 g is equal to $\bold {10^{6} \ \mu g}$

Nano-gram: 1 g is is equal to $\bold {10^{9} \ ng}$

First convert kg to gram,

Since, 1 Kg = 1000 g

2.1 kg = grams of sample

So,

Do the cross multiplication,

$\rm mass\ of\ sample = \dfrac {2.1\ kg \times 1000\ g }{ 1 kg}\\\\\rm mass\ of\ sample =2100 g$

Now, convert 2100 g to nano-grams

Since, 1 g = 1 x 10⁹ ng

2100 g = ng of sample

So,

Do the cross multiplication,

$\rm mass\ of\ sample = \dfrac {2100 g \times 1 \times 10^9 ng }{1\ g}\\\\\rm mass\ of\ sample = 2.1 \times 10^1^2 ng$

Therefore, 2.1 kg of sodium bicarbonate is equal to the 2.1 x 10¹² ng of sample.

To know more about Mass units,

brainly.com/question/489186

3 0

3 years ago

A worker exerts a pulling force on a box. The worker exerts this force by attaching a rope to the box and pulling on the rope so

shusha [124]

Answer:

The magnitude of the pulling force is 20.66% of the gravitational force acting on the box

Explanation:

Accelerated Motion

The net force exerted on a body is the (vector) sum of all forces applied to the body. The net force can be decomposed in its rectangular components and the dynamics of the body can be studied in each direction x,y separately.

Let's start off by calculating the acceleration the worker gives to the box when pulling it. The distance traveled by the box initially at rest in a time t at an acceleration a is given by

$\displaystyle x=\frac{at^2}{2}$

Solving for a

$\displaystyle a=\frac{2x}{t^2}$

$\displaystyle a=\frac{2\cdot 10}{5.12^2}$

$a=0.763\ m/s^2$

Now we analyze the geometric of the forces applied to the box. Please refer to the free body diagram provided below.

The forces in the y-axis must be in equilibrium since no movement takes place there, thus, being g the acceleration of gravity:

$T_y+N=m.g$

There Ty is the vertical component of the tension of the rope, N is the normal force, and m is the mass of the box

The decomposition of T gives us

$T_y=Tsin\theta$

$T_x=Tcos\theta$

Solving the above equation for N

$Tsin\theta+N=m.g$

$N=m.g-Tsin\theta\text{..........[1]}$

Now for the x-axis, there are two forces acting on the box, the x-component of the tension and the friction force Fr. Those forces are not equilibrated, thus acceleration is produced:

$Tcos\theta-F_r=m.a$

Recalling that

$F_r=\mu N$

$Tcos\theta-\mu N=m.a$

Replacing N from [1]

$Tcos\theta-\mu (m.g-Tsin\theta)=m.a$

Operating

$Tcos\theta-\mu m.g+\mu Tsin\theta=m.a$

Solving for T

$T(cos\theta+\mu sin\theta)=m.a+\mu m.g$

$\displaystyle T=\frac{m.a+\mu m.g}{cos\theta+\mu sin\theta}$

$\displaystyle T=m\frac{a+\mu g}{cos\theta+\mu sin\theta}$

We don't know the value of m, thus we'll plug in the rest of the data

$\displaystyle T=m\frac{0.763+0.10\cdot 9.8}{cos36.8^o+0.10 sin36.8^o}$

$T=2.0252m$

Dividing by the weight of the box m.g

$T/(m.g)=2.0252/9.8=0.2066$

Thus, the magnitude of the pulling force is 20.66% of the gravitational force acting on the box

7 0

3 years ago

Why doesn't the earth block out the light between the sun and the moon during a normal month

almond37 [142]

Answer:

Explanation:

6 0

3 years ago

Denis throws a ball downward at an initial speed of 15 m/s from the top of a cliff. (a)

Gennadij [26K]

Answer:

Multiply the time by the acceleration due to gravity to find the velocity when the object hits the ground. If it takes 9.9 seconds for the object to hit the ground, its velocity is (1.01 s)*(9.8 m/s^2), or 9.9 m/s.

Explanation:really sorry if it wrong,i mean reallyyyyy

4 0

3 years ago

Why does conduction occur mainly in the lower atmosphere

Rus_ich [418]

Heat energy is transferred through Earth's atmosphere in three ways: radiation,conduction, and convection. hoped this helped

4 0

3 years ago