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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.
You might be interested in
Can you please help me and can you show your work please
natali 33 [55]

Answer:

1. 25 moles water.

2. 41.2 grams of sodium hydroxide.

3. 0.25 grams of sugar.

4. 340.6 grams of ammonia.

5. 4.5x10²³ molecules of sulfur dioxide.

Explanation:

Hello!

In this case, since the mole-mass-particles relationships are studied by considering the Avogadro's number for the formula units and the molar mass for the mass of one mole of substance, we proceed as shown below:

1. Here, we use the Avogadro's number to obtain the moles in the given molecules of water:

1.5x10^{25}molecules*\frac{1mol}{6.022x10^{23}molecules} =25 molH_2O

2. Here, since the molar mass of NaOH is 40.00 g/mol, we obtain:

1.2mol*\frac{40.00g}{1mol} =41.2g

3. Here, since the molar mass of C6H12O6 is 180.15 g/mol:

45g*\frac{1mol}{180.15g}=0.25g

4. Here, since the molar mass of ammonia is 17.03 g/mol:

20mol*\frac{17.03g}{1mol}=340.6g

5. Here, since the molar mass of SO2 is 64.06 g/mol:

48g*\frac{1mol}{64.06g} *\frac{6.022x10^{23}molecules}{1mol} =4.5x10^{23}molecules

Best regards!

5 0
3 years ago
What is the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen
natta225 [31]
Carbon(C):
number of moles= mass/molar mass(Mr)
=65.5/12
=5.5 moles

Hydrogen(H):
number of moles=mass/molar mass (Mr)
=5.5/1
=5.5 moles

Oxygen (O):
number of moles = mass/molar mass (Mr)
=29.0/16
=1.8 moles

EF= lowest number of moles over each of the elements

So,
C= 5.5/1.8 = 3
H= 5.5/1.8 = 3
O= 1.8/1.8 = 1

Therefore Emperical formula= C3H3O
6 0
2 years ago
What do all the elements in one row of the periodio fable have in common?
Mamont248 [21]

Answer:

Energy levels

Explanation:

Elements in one row of the periodic table have the same energy levels. A row on the periodic table is the horizontal arrangement of elements. These rows are called periods.

There are 7 periods on the periodic table.

  • Each elements on a period begins with an atom having one valence electrons and then ending with completely filled orbitals.
  • Elements in the same period are known to have the same electronic shells which is the energy level.
  • The principal quantum number of their electrons is the same.
4 0
3 years ago
Hello guys what is good! <br><br> What are all the elements of the P block?
Ghella [55]

boron, carbon, nitrogen, oxygen and flourine families in addition to the noble gases.

_________________________________________________________

also to answer the 'hello guys what is good!':nothin u?

__________________________________________

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6 0
2 years ago
What is silicons reactivity level
egoroff_w [7]

Answer:

this is your answer

Explanation:

Silicon, like carbon, is relatively inactive at ordinary temperatures; but when heated it reacts vigorously with the halogens (fluorine, chlorine, bromine, and iodine) to form halides and with certain metals to form silicides.

hope it helps

good day (≧▽≦)

5 0
3 years ago
Read 2 more answers
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