A block of wood has the mass of 180 grams.it is 10 cm long,6 cm wide and 4 cm thick.what is it’s density?

Answer:

6.19⋅109ng

Explanation:

The first thing to do here is to determine the mass in grams of 2.33⋅1020 atoms of oxygen.

To do that, use Avogadro's number to convert the number of atoms to moles, the molar mass of oxygen to convert the moles to grams.

So, Avogadro's number, which acts as the definition of a mole, tells you that in order to have one mole of oxygen, you need to have 6.022⋅1023 atoms of oxygen.

In your case, the sample will be equivalent to

2.33⋅1020 atoms of O ⋅1mole O

                                    6.022⋅1023 atoms of O   =3.869⋅10−4 moles O

Now, oxygen has a molar mass of 15.9994 g mol−1 as listed in the Periodic Table of Elements

This means that your sample will have a mass of

3.869⋅10−4 moles O   ⋅15.9994 g

                                       1 mole O           =6.190⋅10−3g

Finally, you can convert the mass from grams to nanograms by using the conversion factor  

1 g=109ng

You will end up with

6.190⋅10−3g ⋅109ng

                        1g=6.19⋅106ng

meaning The answer is rounded to three sig figs.

Answer:

C. Iron oxide is a mixture of iron and oxygen

Answer:

3 electrons

Explanation:

That means there are 3 electrons in a lithium atom. Looking at the picture, you can see there are two electrons in shell one and only one in shell two.

Answer:

10 degrees C

Explanation:

Answer:

Explanation:

Baby pigs, dolphins, bats and elephants all drink milk! Because the babies rely on their mother's milk to live, the mammal mommies have to care for their young. ... Through copying their mothers, baby mammals learn everything they need to survive

Answer:

by be young

Explanation:

wow just use you brain

Explanation:

2CO2 + 3H2O + 4Br2

C = 2

O = 5

H = 6

Br =8

Answer:

b is the answer .............

Answer:

The asnswer is c

Explanation:

Gope it helps

a. pH=2.07

b. pH=3

c. pH=8

pH=-log [H⁺]

a) 0.1 M HF Ka = 7.2 x 10⁻⁴

HF= weak acid

[tex]\tt [H^+]=\sqrt{Ka.M}\\\\(H^+]=\sqrt{7.2.10^{-4}\times 0.1}\\\\(H^+]=8.5\times 10^{-3}\\\\pH=3-log~8.5=2.07[/tex]

b) 1 x 10⁻³ M HNO₃

HNO₃ = strong acid

[tex]\tt pH=-log[1\times 10^{-3}]=3[/tex]

c) 1 x 10⁻⁸ M HCl

[tex]\tt pH=-log[1\times 10^{-8}]=8[/tex]

Mass of oxygen gas produced : 14.08 g

Reaction

2H₂O(l)⇒2H₂(g)+O₂(g)

mol of H₂O (MW=18 g/mol) :

[tex]\tt \dfrac{20}{18}=1.1[/tex]

mol O₂ :

[tex]\tt \dfrac{1}{2}\times 1.1=0.55[/tex]

mass O₂ (theoretical) :

[tex]\tt 0.55\times 32=17.6~g[/tex]

mass O₂ (actual) :

[tex]\tt =\%yield\times theoretical\\\\=0.8\times 17.6=14.08[/tex]

Answer:

4.4 L

Explanation:

Given data:

Initial number of mole = 0.55 mol

Initial volume = 2.0 L

Final volume = ?

Final number of moles = 1.20 mol

Temperature and pressure = constant

Solution:

Formula:

V₁/n₁   = V₂/n₂

V₂ = V₁×n₂/n₁  

V₂ = 2.0 L ×1.20 mol/ 0.55 mol

V₂ = 2.4 L.mol / 0.55 mol

V₂ = 4.4 L

The volume of the gas is 31.3 L.

Using the formula;

PV = nRT

P = pressure of the gas

V = volume of the gas

n = Number of moles of the gas

R  gas constant

T = temperature

To obtain the volume;

V = nRT/P

V = 1.20 mol * 0.082 atmLmol-1K-1 * 318 K/7.0 atm

V = 31.3 L

Learn more about volume:

Answer:

Acid

Explanation:

acid

Answer:

An acid

Explanation:

H2OSO4 is Sulfuric Acid

Answer:

just watch the video, what does it start with, write that down for each trial, then what does it end with, then starting mass - ending mass is the change mass

Answer:

Percent yield = 90.9%

Explanation:

Given data:

Mass of CaCO₃ = 50.0 g

Mass of CO₂ produced = 20.0 g

Percent yield = ?

Solution:

Chemical equation:

CaCO₃ →  CaO + CO₂

Number of moles of CaCO₃:

Number of moles = mass/molar mass

Number of moles = 50.0 g/ 100.1 g/mol

Number of moles = 0.5 mol

Now we will compare the moles of CO₂ with CaCO₃.

                      CaCO₃          :        CO₂

                          1                :           1

                       0.5               :          0.5

Mass of CO₂: Theoretical yield

Mass = number of moles × molar mass

Mass = 0.5 mol × 44 g/mol

Mass = 22 g

Percent yield:

Percent yield = ( actual yield / theoretical yield ) × 100

Percent yield = (20.0 g/ 22.0 g) × 100

Percent yield = 0.909 × 100

Percent yield = 90.9%

Answer:

create and destroyed

Explanation:

its just simple science

Answer:

Create bonds

Broken

Explanation:

Energy is required to created bonds in a molecule and released when bonds are broken.

Energy is needed in chemical reactions to do work.

Answer: A scientific model is a physical and mathematical and conceptual representation of a system of ideas, events or processes.

ANd also for your second question i dont know what you mean?

Explanation:

Scientists work to recognize and comprehend patterns in our world by applying their scientific expertise to provide predictions about the patterns.

In a range of scientific specialties, from chemistry and physics to biology and the Earth sciences, research models are employed to explain and forecast the behavior of real things or systems. The ability to depict things that are too little or enormous, explain either past or present, and forecast the future are all advantages of employing model beyond nature.

Models can help you visualize something is difficult to see or understand. Models can help in scientific predictions, process comprehension, and concept communication. Because it frequently includes a variety of hypotheses or facts, an evolutionary theory varies from other general explanations. A science simulation may be used to verify a scientific theory or to demonstrate a scientific model.

To know more about Scientific model visit:

https://brainly.com/question/4737073

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Answer:

vitreous

Explination:

The vitreous is the gel-like fluid that fills your eye. It's full of tiny fibers that attach to your retina (the light-sensitive layer of tissue at the back of the eye). As you get older, the fibers of your vitreous pull away from the retina.

Answer:

The vitreous

Explanation:

Answer:

Explanation:

The percentage error of a certain measurement can be found by using the formula

[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\[/tex]

actual mass = 24.3

error = 24.3 - 14.7 = 9.6

We have

[tex]p(\%) = \frac{9.6}{24.3} \times 100 \\ = 39.506172839...[/tex]

We have the final answer as

Hope this helps you

Answer:

B

Explanation:

D=S×T

=120km/h×4hrs

=480km

Answer:

the answer is b

Explanation:

this is the answer :)

Answer:

Atomic number 29

Atomic mass 63.546 g.mol -1

Electronegativity according to Pauling 1.9

Density 8.9 g.cm-3 at 20°C

Melting point 1083 °C

Copper has a melting point of 1083.4 +/- 0.2°C, boiling point of 2567°C, specific gravity of 8.96 (20°C), with a valence of 1 or 2. Copper is reddish colored and takes a bright metallic luster. It is malleable, ductile, and a good conductor of electricity and heat.

Answer:

220.8L

Explanation:

Given parameters:

Initial volume  = 50L

Initial temperature = 15°C  = 288K

Initial pressure = 640mmHg

Final temperature  = 45°C  = 318K

Final pressure  = 160mmHg

Unknown:

Final volume  = ?

Solution:

Using the combined law;

        [tex]\frac{p_{1}v_{1} }{T_{1} }[/tex]  = [tex]\frac{p_{2}v_{2} }{T_{2} }[/tex]  

p,v and T are pressure, volume and Temperature

    [tex]\frac{640 x 50}{288}[/tex]  = [tex]\frac{160 x v_{2} }{318}[/tex]

     160 x 288 x v₂ = 640 x 50 x 318

                         v₂ = 220.8L

Answer:

The best solution is Strong acid

Explanation:

add me on snap Andy142512

A solution that has a pH of 2 is a strong acid solution.

Explanation:

                            [tex]pH=-\log[H^+][/tex]

So, from this, we can conclude that solution with a pH of 2 which is less than 7, hence strong acidic solution.

Learn more about the pH of the solution here:

brainly.com/question/4975103?referrer=searchResults

brainly.com/question/172153?referrer=searchResults

Answer:

yes

Explanation:

Answer:

there is nothing follow that

Explanation:

Answer:

A chemical change

Explanation:

From the observation, a chemical change has ensued.

A chemical change is one in which new kind of matter is formed. It is always accompanied by energy changes . This process is not easily reversible.

Answer:

Lateral Inversion

Explanation:

in my opinion it's true!!!

Answer:

It's D

Explanation: