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2 years ago

12

The first 18 elements in the periodic table have which of the following important properties? a. They have the largest atomic nu

mbers c. Most occur as liquids at room temperature b. They do not typically combine with other elements to form compounds d. These elements make up most of the matter of the known universe Please select the best answer from the choices provided A B C D

2 answers:

fenix001 [56]2 years ago

7 0

<span>d. These elements make up most of the matter of the known universe</span>

GalinKa [24]2 years ago

5 0

Its actually a and possibly d but more likely a if they are the first 18 elements

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What is an example of a solid turning into another state of matter?

Rom4ik [11]

Answer:

Explanation:

Let me start with a simple one:

An ice cube ( solid ) changing into water ( a liquid )

Another example:

Dry ice ( solid ) submiling.

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4 0

2 years ago

15.0 g of cream at 16.4 °C are added to an insulated cup containing 100.0 g of coffee at 86.5 °C. Calculate the equilibrium temp

Marta_Voda [28]

115 grams total

15/115= 13%

109/115= 87%

.13x 16.4= .277

.87x 86.5= 75.255

75.255+.277= 75.532 deg C
or 75.5 as 3 significant digits

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2 years ago

Assuming the same temperature and pressure for each gas, how many milliliters of carbon dioxide are produced from 16.0 mL of CO?

Vlada [557]

Answer:

$V_{CO_2}=16.0mL$

Explanation:

Hello,

In this case, given that the same temperature and pressure is given for all the gases, we can notice that 16.0 mL are related with two moles of carbon monoxide by means of the Avogadro's law which allows us to understand the volume-moles relationship as a directly proportional relationship. In such a way, since in the chemical reaction:

$2CO(g)+O_2(g)\rightarrow 2CO_2(g)$

We notice two moles of carbon monoxide yield two moles of carbon dioxide, therefore we have the relationship:

$n_{CO}V_{CO}=n_{CO_2}V_{CO_2}$

Thus, solving for the yielded volume of carbon dioxide we obtain:

$V_{CO_2}=\frac{n_{CO}V_{CO}}{n_{CO_2}} =\frac{2mol*16.0mL}{2mol}\\ \\V_{CO_2}=16.0mL$

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4 0

2 years ago

What name is given to bonds that involve the sharing of electrons? What name is given to bonds that involve the sharing of elect

Alina [70]

Answer:

Covalent bonds.

Explanation:

Covalent bonds are intermolecular bonds which involve the sharing of electrons between atoms or molecules and ions with close or near electronegativity values.

This usually form molecules. This is also the sharing of electrons donated by one of the atoms or by both of the atoms to form a molecule and at the same time obtain a stable octet state.

3 0

2 years ago

How many grams of KCl (s) has been produced from the thermal decomposition of KClO3 (s) that produced 50.0 mL of O2 (g) at 25 de

geniusboy [140]

Answer:

The mass is $m_{KCl} = 0.102 \ g$

Explanation:

From the question we are told that

The volume of oxygen produced is $V_o = 50mL = 50 *10^{-3} L$

The temperature is $T = 25 ^oC = 25* 273 = 298 K$

The pressure is $P = 1.0\ atm$

From the ideal gas law we have that

$PV = nRT$

Where R is the gas constant with the value

$R = 0.08206 \ atm \cdot L /mol K$

n is the number of moles making it the subject of the formula

$n = \frac{PV}{RT}$

Substituting values

$n = \frac{1 * (50 *10^{-3}) }{0.08206 * 298}$

$n = 2.045 *10^{-3} \ mol$

From the chemical equation

one mole of $KClO_3$ produces one mole of kCl and $\frac{3}{2}$ of oxygen

x mole of $KClO_3$ produces x mole of kCl and $2.045 *10^{-3} \ mol$ of oxygen

So $x = \frac{2.045 *10^{-3}}{\frac{3}{2} }$

$x = \frac{2}{3} * 2.045 *10^{-3}$

$x = 1.363 *10^{-3} \ mol$

Now the molar mass of KCl is a constant with a value

$M_{KCl} = 74.55 g/mol$

Now the mass of KCl is mathematically evaluated as

$m_{KCl} = x * M_{KCl}$

Substituting values

$m_{KCl} = 1.363 *10^{-3} * 74.55$

$m_{KCl} = 0.102 \ g$

6 0

2 years ago