Week 12.1 & 2
Monday/Tuesday 11/30 - 12/01/20
19
Talling
1. Most elements that form a zigzag line in the
periodic table belong to which major group?
2. True or False- metalloids make up most of the
elements on the periodic table.
3. Would Co, and NaCl be considered an element
or compound? Explain.
os E 240 PM
11/30/20

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:

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:

yes

Explanation:

Explanation:

2CO2 + 3H2O + 4Br2

C = 2

O = 5

H = 6

Br =8

Answer:

0.6

Explanation:

Answer:

????? questions there no question

Answer:

what

Explanation:

Answer:

10 degrees C

Explanation:

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:

B

Explanation:

D=S×T

=120km/h×4hrs

=480km

Answer:

the answer is b

Explanation:

this is the answer :)

Answer:

C. Iron oxide is a mixture of iron and oxygen

Answer:

Lateral Inversion

Explanation:

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:

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:

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:

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:

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: 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

#SPJ2

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

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:

It's D

Explanation:

Answer:

Acid

Explanation:

acid

Answer:

An acid

Explanation:

H2OSO4 is Sulfuric Acid

in my opinion it's true!!!

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:

there is nothing follow that

Explanation:

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]

Answer:

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

Answer:

The asnswer is c

Explanation:

Gope it helps

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

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