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MArishka [77]
3 years ago
15

4. Which of these metals is a pure element? Brass Bronze Silver Steel 5. C is the correct chemical symbol for ....... Calcium Ca

rbon Chlorine Cobalt 6. Which of these substances is an element? Air Fire Oxygen Water
Chemistry
2 answers:
pickupchik [31]3 years ago
5 0

Answer:

4) Silver (Rest are alloys)

5) Carbon (It stands for C)

6) Oxygen (Rest of them are either compounds or mixtures)

Gala2k [10]3 years ago
3 0

Answer:

4) Silver

5) Carbon

6) Oxygen

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Romashka-Z-Leto [24]
A physical change.......
7 0
3 years ago
An ideal gas is in a sealed rigid container. The average kinetic energy of the gas molecules depends most on An ideal gas is in
sergejj [24]

Answer:

The temperature of the gas.

Explanation:

According to the kinetic molecular theory, the molecules of a substance are in constant random motion.

If an ideal gas is contained is a sealed rigid container, the average velocity of the gas molecules is dependent of the temperature of the gas.

Recall that temperature is defined as the average kinetic energy of the molecules of a body.

5 0
2 years ago
PLEASE I NEED HELP ASAP!!!!
miv72 [106K]

The percent yield of the calcium hydroxide is 84.5%.

<h3>What is stoichiometry?</h3>

Stoichiometry enables us to obtain the mass of a substance form the equation of the reaction.

The equation of the reaction is;

CaCO3 + 2HCl -----> CaCl2 + CO2 + H2O

Number of moles of X = 40.0 grams/100 g/mol = 0.4 moles

Number of moles of HCl = 850/1000 * 1 M = 0.85 moles

If 1 mole of CaCO3 reacts with 2 moles of HCl

0.4 moles of  CaCO3 reacts with  0.4 moles  * 2 moles/1 mole

= 0.8 moles of HCl

Hence X is the limiting reactant.

The reaction is 1:1 then the amount of CO2  produced is 0.4 moles

Mass of CO2 = 0.4 CO2 * 44 g/mol = 17.6 g

2) The reaction equation is; 2NaOH + CaCO3 --->  Ca(OH)2 + Na2CO3

Number of moles of X = 25.0 grams/100 g/mol =  0.25 moles

Number of moles of NaOH= 40/1000 L * 2 M = 0.08 moles

If 1 mole of X reacts with 2 moles of NaOH

0.25 moles  reacts with   0.25 moles   * 2 moles /1 mole

= 0.5 moles

NaOH is the limiting reactant

2 moles of NaOH produces 1 mole of CO2

0.08 moles of NaOH produces 0.08 moles * 1 mole/2 moles

= 0.04 moles of CO2

Theoretical yield of CO2 =  0.04 moles of CO2 * 74 g/mol = 2.96  g

Percent yield = 2.5 g/ 2.96  g * 100

= 84.5%

Learn ore about percent yield:brainly.com/question/17042787

#SPJ1

5 0
1 year ago
Please answer fast, I will give brainliest if correct!
gizmo_the_mogwai [7]

Answer:

Explanation: 30 min

5 0
2 years ago
Which of the following statements related to S N1 reactions is not true? - The heterolysis of a bond between atoms which do not
Varvara68 [4.7K]

Answer:

The charged carbon atom of a carbocation has a complete octet of valence shell electrons

Explanation:

A charged carbon atom of a carbocation has a valence shell that is not filled, <u>that's why it acts as an electrophile (or a Lewis base)</u>. This unfilled valence shell is also the reason of the nucleophilic attack that takes place during the second step of a SN1 reaction.

6 0
3 years ago
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