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viva [34]
3 years ago
10

How are elements arranged in the Periodic Table? A. by their properties B. alphabetically C. by how much they are worth D. in th

e order they were discovered 2. (10 pt) Which is the correct symbol for the element silicon? A. SI B. S C. Si D. Sil 3. (10 pt) All atoms of an element are ________ . A. flammable B. visible under a microscope C. alike D. different 4. (10 pt) Elements that are usually shiny and good conductors of heat and electricity are known as ________________. A. gases B. metals C. solids D. nonmetals 5. (10 pt) The most recent model of an atom is the _______________. A. Bohr model B. Einstein model C. Nucleus model D. Electron Cloud model 6. (10 pt) Elements that are usually dull, brittle, and do not conduct electricity are known as A. gases B. metals C. solids D. nonmetals 7. (10 pt) Elements join together to form A. compounds B. ions C. protons D. atomic masses 8. (10 pt) Which picture best shows an atom? A. B. C. D. 9. (10 pt) In order for a chemical reaction to take place, a certain amount of _______________ must be present. A. heat B. friction C. chemicals D. energy 10. (10 pt) Enzymes are ____________ in the body that speed up chemical reactions. A. catalysts B. cells C. concentrations D. chloroplasts
Chemistry
1 answer:
algol133 years ago
5 0
Im on the same test.
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Based on the activity series of metal, which reaction with water will not happen?
laila [671]

Answer:

B

Explanation:

B, H2O + Na The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive. Lithium, sodium, and potassium all react with water,

5 0
3 years ago
Which substance has a mass is 13.5 grams, and its volume is 5 cm 3.
solmaris [256]

Answer:

Substance is Aluminium

Explanation:

We are given;

Mass; m = 13.5 grams

Volume; V = 5 cm³

Formula for density is;

density = m/V

Density = 13.5/5

Density = 2.7 g/cm³

From the table attached, we can see that the element with a corresponding density of 2.7 is Aluminium

5 0
3 years ago
Carbon monoxide (CO) reacts with hydrogen (H2) to form methane (CH4) and water (H2O).
Artemon [7]

Answer:

5.9x10^-2 M

Explanation:

Step 1:

Data obtained from the question. This includes the following:

Concentration of CO, [CO] = 0.30 M

Concentration of H2, [H2] = 0.10 M

Concentration of H2O, [H2O] = 0.020 M

Equilibrium constant, K = 3.90

Concentration of CH4, [CH4] =..?

Step 2:

The balanced equation for the reaction. This is given below:

CO(g) + 3H2(g) <=> CH4(g) + H2O(g)

Step 3:

Determination of the concentration of CH4.

The expression for equilibrium constant of the above equation is given below:

K = [CH4] [H2O] / [CO] [H2]^3

3.9 = [CH4] x 0.02/ 0.3 x (0.1)^3

Cross multiply to express in linear form

[CH4] x 0.02= 3.9 x 0.3 x (0.1)^3

Divide both side by 0.02

[CH4] = 3.9 x 0.3 x (0.1)^3 /0.02

[CH4] = 5.9x10^-2 M

Therefore, the equilibrium concentration of CH4 is 5.9x10^-2 M

5 0
3 years ago
How many moles are in 5g of Al?<br><br>A.0.185<br>B.18.5<br>C.5.4<br>D.135
Lapatulllka [165]
I got 134.91 but if you round it you’ll get 135
3 0
3 years ago
Read 2 more answers
What can you summarize about the use of acid-base indicators?
densk [106]

An acid-base indicator is used to identify the presence of an acid or base. These indicators exhibit different colors depending on the solution that they are in. They are especially useful when completing titrations to determine the molarity of an unknown substance and is denoted as option D.

<h3>What is Titration?</h3>

This is done in the laboratory and involves the slow addition of one solution of a known concentration to a known volume of another solution of unknown concentration.

Acid-base indicators are used to determine the presence of an acid or base in a solution which is based on the colors seen when performing the chemical reaction.

It is used to calculate the the molarity of an unknown substance through the knowledge of the other parameters which is therefore the reason why option D was chosen as the most appropriate choice.

Read more Acid-base indicators  here brainly.com/question/2815636

#SPJ1

6 0
1 year ago
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