What is the difference between atom and it’s ion ?

1. The

rodikova [14]

Answer:

1. Proton = electron if the element is not in an ionic state

proton = atomic number

3 0

3 years ago

the half life of a certain element is 100 days. how many half-lives will it be before only one-fourth of this element reamains

Rama09 [41]

Answer:

200 Days

Explanation:

Usually not so good in chemistry, but this is math!

Half life means in this time half goes away. What happens when two half lives pass? half of what was remaining goes away. Maybe an example will make it more clear.

Say we start with 100 grams. After the amount of time for the half life to pass completes, we have 50, or half of the original amount. The half life time passes again and THAT gets cut in half to 25 grams. this is 1/4 of the original (Hey, what we're looking for.) Just to make it clear what is happening after another half life 1/8 remains, so it goes from The starting amount to 1/2 to 1/4 to 1/8 and so on, it keeps getting cut in half.

So how many times do we have to cut 1 in half until we get to 1/4? Twice as was shown before. Now, two half lives for this element is what? 100+100 days. So 200 Days.

4 0

3 years ago

Silicon carbide, SiC, is commonly known as carborundum. This hard substance, which is used commercially as an abrasive, is made

mrs_skeptik [129]

Mass of SiC = 2 g

<h3>Further explanation</h3>

Given

Reaction

SiO₂(s) + 3C(s) → SiC(s) + 2CO(g)

3.00 g of SiO₂

4.50 g of C

Required

mass of SiC

Solution

mol SiO₂ (MW=60,08 g/mol) :

= 3 g : 60.08 g/mol

= 0.0499

mol C(Ar = 12 g/mol) :

= 4.5 g : 12 g/mol

= 0.375

mol : coefficient of reactants =

SiO₂ : 0.0499/1 = 0.0499

C : 0.375/3 = 0.125

SiO₂ as a limiting reactant(smaller ratio)

Mol SiC based on mol SiO₂ = 0.0499

Mass SiC :

= mol x MW

= 0.0499 x 40,11 g/mol

= 2 g

3 0

3 years ago

Two different proteins X and Y are dissolved in aqueous solution at 37 °C. The proteins bind in a 1:1 ratio to form XY. A soluti

aleksklad [387]

Answer:

Kc of reaction is 20.

Explanation:

The two proteins are X and Y.

The [X] = 1mM

[Y]=1mM

At equilibrium, [X] = 0.2mM [Y] = 0.2mM

we know that equilibrium constant is:

Kc= $\frac{[Products]}{[Reactants]}=\frac{[XY]}{[X][Y]}$

[XY]= 1-0.20=0.80 mM

putting values:

Kc= $\frac{0.80}{0.20X0.20}=20$

8 0

3 years ago

The density of silver is 10.5 g/cm3. What is the mass (in kilograms) of a cube of silver that measures 0.94 m on each side?

Rzqust [24]

Answer:

8721.132 Kg.

Explanation:

The following data were obtained from the question:

Density (D) of silver = 10.5 g/cm³

Length (L) of silver = 0.94 m

Mass (m) of silver =.?

Next, we shall determine the volume of silver. This can be obtained as follow:

Volume = Length × Length × Length

Volume = L × L × L

Volume = L³

Length (L) of silver = 0.94 m

Volume (V) of silver =?

Volume (V) of silver = 0.94³

Volume (V) of silver = 0.830584 m³

Next, we shall convert 0.830584 m³ to cm³. This can be obtained as follow:

1 m³ = 1×10⁶ cm³

Therefore,

0.830584 m³ = 0.830584 m³ / 1 m³ × 1×10⁶ cm³

0.830584 m³ = 830584 cm³

Therefore, 0.830584 m³ is equivalent 830584 cm³.

Thus, the volume of the silver is 830584 cm³.

Next, we shall determine the mass of the silver. This can be obtained as follow:

Density (D) of silver = 10.5 g/cm³

Volume of the silver = 830584 cm³.

Mass of silver =.?

Density = mass /

10.5 = mass of silver /830584

Cross multiply

Mass of silver = 10.5 × 830584

Mass of silver = 8721132 g

Finally, we shall convert the mass of silver, 8721132 g to kilogram (kg). This can be obtained as follow:

1000 g = 1 Kg

Therefore,

8721132 g = 8721132 g / 1000 g × 1 Kg

8721132 g = 8721.132 Kg

Therefore, the mass of each cube of silver is 8721.132 Kg

3 0

3 years ago