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3 years ago

Can you guys help me with 8&9 THANK YOUU

Chemistry

1 answer:

zlopas [31]3 years ago

8 0

number 8 the list is hydrogen,magnesium,silicon and oxygen and there are 4elements

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Help! 7th Grade Math!

vagabundo [1.1K]

Answer:

Explanation: Trust me

6 0

3 years ago

What are the molarity and osmolarity of a 1-liter solution that contains half a mole of calcium chloride? How many molecules of

givi [52]

Answer:

Molarity = 0.5 M

Osmolarity = 0.5 x 2 = 1 Osmpl.

Molecules of Cl2 = 6.02 x $10^{23}$ / 4= 1.505 x $10^{23}$ no. of molecules

Explanation:

If we add half mole in 1L volume than molarity will obviously be 0.5 M.

The osmolarity is molarity multiplies by number of dissociates of solute that for CaCl2 are 2. So, 2 x 0.5 = 1

Half will be molecules of Ca and half will be of Cl2 for 0.5M.

6 0

3 years ago

1.00g of a metallic element reacts completely with 300cm3 of oxygen at 298K and 1 atm pressure to form an oxide which contains O

elena55 [62]

Answer:

The metal is most likely calcium which has a molar mass of 40.078 g

<em>Note: The question is incomplete. The complete question is given below:</em>

1.00g of a metallic element reacts completely with 300cm3 of oxygen at 298K and 1 atm pressure to form an oxide which contains O2– ions. The volume of one mole of gas at this temperature and pressure is 24.0dm3 .

What could be the identity of the metal?

<em>A calcium B magnesium C potassium D sodium</em>

Explanation:

Number of moles of the oxygen gas reacted is first determined:

Volume of oxygen gas = 300 cm³ = 0.30 dm³

1 mole of a gas occupies 24.0 dm³ at this temperature and pressure

Number of moles of oxygen gas that will occupy 0.30 dm³ = 0.3/24 = 0.125 moles

Let M be represent the metallic element. The equation of the reaction will be:

2M + O₂ ----> 2MO

From the equation of reaction;

2 moles of the metal reacts with 1 mole of oxygen gas

2 * 0.125 moles of the metal will react with 300 cm³ of oxygen = 0.025 moles

Since the mass of the metal that reacted with oxygen is 1.0 g, therefore, 1.0 g of the metal = 0.025 moles

mass of 1 mole of the metal = 1 /0.025 = 40.0 g

Therefore, the metal is most likely calcium which has a molar mass of 40.078 g

5 0

3 years ago

What is the difference between a quantity and a unit?

Irina-Kira [14]

$Question$

What is the difference between a quantity and a unit?

Answer:

Physical quantities are a characteristic or property of an object that can be measured or calculated from other measurements. Units are standards for expressing and comparing the measurement of physical quantities. All units can be expressed as combinations of four fundamental units.

Hope this helps!!!

$xXxAnimexXx$

4 0

3 years ago

What is the mass, in grams, of potassium in 12.5 g of k

anyanavicka [17]

Answer:

Option d)3.32 g is correct.

Explanation:

hope this helps

7 0

3 years ago