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3 years ago

Why is potassium placed in the periodic table where it is?

1 answer:

6 0

Potassium is placed where it is based on its properties and it's reactivity. It's also placed there based on it's atomic number.

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If 23.5 g of ammonia (NH3) is dissolved in 1.0 L of solution, what is the molarity?

r-ruslan [8.4K]

Answer:

1.38 M

Explanation:

Need to use the Molarity equation M=n/L

23.5g/ 17.031g/mol NH3 = 1.38 moles

1.38 moles/ 1.0 L = 1.38 M

4 0

2 years ago

How many atoms are in 187 g of Calcium?

N76 [4]

Atomic mass Calcium ( Ca) = 40.078 u.m.a

40.078 g --------------- 6.02x10²³ atoms
187 g ------------------- ??

187 x ( 6.02x10²³) / 40.078 =

1.125x10²⁶ / 40.078 = 2.808x10²⁴ atoms

hope this helps!

4 0

3 years ago

True or false? Kinetic energy depends only on an object’s speed and velocity. Help!

AlekseyPX

False, kinetic energy depends on an objects mass and speed

8 0

3 years ago

Read 2 more answers

Difference between sodium ion and sodium atom. (give in points not in paragraph)

Natali5045456 [20]

Answer:

Explanation:

SODIUM ATOM;

SODIUM ATOM IS NEUTRAL

SODIUM ION;

IT IS A CHARGED SPECIE WITH A CHARGE OF +1

SODIUM ATOM:

THE NUMBER OF PROTONS AND ELECTRONS ARE SAME ie:11

SODIUM ION:

NUMBER OF PROTONS AND ELECTRONS ARE NOT SAME ie. ELETRON: 10, PROTONS:11

HOPE IT WILL HELP:)

3 0

2 years ago

When copper metal is added to nitric acid, the following reaction takes place

zlopas [31]

Answer:

The volume of NO₂ gas collected over water at 25.0 °C is 1.68 Liters.

Explanation:

$Cu (s) + 4 HNO_3 (aq) \rightarrow Cu(NO_3)_2 (aq) + 2 H_2O (l) + 2 NO_2 (g)$

Moles of copper = $\frac{2.01 g}{63.55 g/mol}=0.03163 mol$

According to reaction, 1 mol of copper gives 2 moles of nitrogen dioxide gas.

Then 0.03613 moles of copper will give:

$\frac{2}{1}\times 0.03163 mol=0.06326 mol$ of nitrogen dioxide gas

Moles of nitrogen dioxide gas = n = 0.06326 mol

Pressure of the gas = P

P = Total pressure - vapor pressure of water

P = 726 mmHg - 23.8 mmHg = 702.2 mmHg

P = 0.924 atm (1 atm = 760 mmHg)

Temperature of the gas = T = 25.0°C =298.15 K

Volume of the gas = V

$PV=nRT$

$V=\frac{0.06326 mol\times 0.0821 atm L/mol K\times 298.15 K}{0.924 atm}$

V = 1.68 L

The volume of NO₂ gas collected over water at 25.0 °C is 1.68 Liters.

3 0

3 years ago