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3 years ago

SOMEONE HELP NO LINKS PLZ answer Questions 1–6 based on Figure 1.

Chemistry

1 answer:

Bogdan [553]3 years ago

6 0

Answer:

element argon, protons 18 , electrons 18 , outer most energy level 8

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A 20.38 gram sample of cobalt is heated in the presence of excess sulfur. A metal sulfide is formed with a mass of 31.47 g. Dete

Viefleur [7K]

Answer: The empirical formula of the metal sulfide is $CoBr_{2}$ .

Explanation:

Given: Mass of metal = 20.38 g

Mass of metal sulfide = 31.47 g

Moles is the mass of a substance divided by its molar mass.

So, moles of cobalt (molar mass = 59 g/mol) are as follows.

$Moles = \frac{mass}{molarmass}\\= \frac{20.38 g}{59 g/mol}\\= 0.345 mol$

Moles of bromine (molar mass = 80 g/mol) are as follows.

$Moles = \frac{(31.47 - 20.38) g}{80 g/mol}\\= \frac{11.09 g}{80 g/mol}\\= 0.138 mol$

Now, the ratio of number of moles of cobalt and number of moles of bromine are as follows.

Moles of Co : Moles of Br = 1 : 2

Hence, the empirical formula is $CoBr_{2}$ .

Thus, we can conclude that the empirical formula of the metal sulfide is $CoBr_{2}$ .

6 0

3 years ago

Unit 3: Energy

Mazyrski [523]

Answer:

What forms of energy does a burning candle give out?

The burning candle is converting chemical energy—stored in the hydrocarbon bonds in the wax—into thermal (heat) and radiant (light) energy.

What questions do you have about energy?

Can momentum be hidden to human eyes like how kinetic energy can be hidden as heat?
Can you go fast enough to get enough mass to become a black hole?
How can a material at a certain temperature have all of its molecules at the same energy?
How can we travel to the past?

8 0

3 years ago

How did Mendeleev organize the elements in the periodic table?

iren2701 [21]

It is the LAST one in the options.

7 0

4 years ago

Whenever a body is in motion, there is always ____ to oppose the motion.

seropon [69]

Answer:

Force

Explanation:

7 0

3 years ago

Unit: Stoichiometry

Reika [66]

Answer:

1. 2.41 × 1023 formula units

2. 122 L

3. 7.81 L

Explanation:

1. Equation of the reaction: 2 Na(NO3) + Ca(CO3) ---> Na2(CO3) + Ca(NO3)2

Mole ratio of NaNO3 to CaCO3 = 2 : 1

Moles of CaCO3 = mass/molar mass

Mass of CaCO3 = 20 g; molar mass of CaCO3 = 100 g

Moles of CaCO3 = 20 g/100 g/mol = 0.2 moles

Moles of NaNO3 = 2 × 0.2 moles = 0.4 moles

1 Mole of NaNO3 = 6.02 × 10²³ formula units

0.4 moles of NaNO3 = 0.4 × 6.02 × 10²³ = 2.41 × 1023 formula units

2. Equation of reaction : 2 H2O ----> 2 H2 + O2

Mole ratio of oxygen to water = 1 : 2

At STP contains 6.02 × 10²³ molecules = 1 mole of water

6.58 × 10²⁴ molecules = 6.58 × 10²⁴ molecules × 1 mole of water/ 6.02 × 10²³ molecules = 10.93 moles of water

Moles of oxygen gas produced = 10.93÷2 = 5.465 moles of oxygen gas

At STP, 1 mole of oxygen gas = 22.4 L

5.465 moles of oxygen gas = 5.465 moles × 22.4 L/1 mole = 122 L

3.Equation of reaction: 6 K + N2 ----> 2 K3N

Mole ratio of Nitrogen gas and potassium = 6 : 1

Moles potassium = mass/ molar mass

Mass of potassium = 90.0 g, molar mass of potassium = 39.0 g/mol

Moles of potassium = 90.0 g / 39.0 g/mol = 2.3077moles

Moles of Nitrogen gas = 2.3077 moles / 6 = 0.3846 moles

At STP, 1 mole of nitrogen gas = 22.4 L

0.3486 moles of oxygen gas = 0.3486 moles × 22.4 L/1 mole = 7.81 L

7 0

3 years ago