__SIO2+__HF--> __ H2SIF6+ __H2O balanced equation

earnstyle [38]

We need the reading for this I think

4 0

3 years ago

Biacetyl, the flavoring that makes margarine taste "just like butter," is extremely stable at room temperature, but at 200°C it

Sholpan [36]

Answer:

3.91 minutes

Explanation:

Given that:

Biacetyl breakdown with a half life of 9.0 min after undergoing first-order reaction;

As we known that the half-life for first order is:

$t__{1/2}}= \frac{0.693}{k}$

where;

k = constant

The formula can be re-written as:

$k = \frac{0.693}{t__{1/2}}$

$k = \frac{0.693}{9.0 min}$

$k = 0.077 min^{-1}$

Let the initial amount of butter flavor in the food be $(N_0)$ = 100%

Also, the amount of butter flavor retained at 200°C $(N_t)$ = 74%

The rate constant $k = 0.077 min^{-1}$

To determine how long can the food be heated at this temperature and retain 74% of its buttery flavor; we use the formula:

$\frac{N_t}{N_0}= -kt$

$t = - (\frac{1}{k}*In\frac{N_t}{N_0} )$

Substituting our values; we have:

$t = - (\frac{1}{0.077}*In\frac{74}{100} )$

t = 3.91 minutes

∵ The time needed for the food to be heated at this temperature and retain 74% of its buttery flavor is 3.91 minutes

4 0

3 years ago

I NEED HELP WITH 1-4 PLEASE ASAP!!!

Varvara68 [4.7K]

Answer:

1 is the same 3 is pure substance 4 is different

Explanation:

not sure about 2

5 0

2 years ago

Which notation designates a possible value for a principal energy level in an atom?

Nata [24]

Answer:

2

Explanation:

There are four quantum numbers:

Principal quantum number (n)

Azimuthal quantum number (l)

Magnetic quantum number (ml)

Principal quantum number (n)

It tell about the energy levels. It is designated by n.

For example,

If n =2

It means there are two energy level present.

Azimuthal quantum number (l)

The azimuthal quantum number describe the shape of orbitals. Its value for s, p, d, f... are 0, 1, 2, 3. For l=3

(n-1)

4-1 = 3

it means principle quantum is 4 and electron is present in f subshell.

Magnetic quantum number (ml)

It describe the orientation of orbitals. Its values are -l to +l. For l=3 the ml will be -3 -2 -1 0 +1 +2 +3.

Spin quantum number (ms)

The spin quantum number tells the spin of electron either its clock wise (+1/2) or anti clock wise (-1/2).

If the electron is added in full empty orbital its spin will be +1/2 because it occupy full empty. If electron is already present and another electron is added then its spin will be -1/2.

3 0

2 years ago

A 100.0 g sample of aluminum released 1680 calories when cooled from 100.0c to 20.0 c what is the specific heat of the metal

vovangra [49]

Answer:

The specific heat of aluminium is 0.8792 J/g °C or 0.21 Cal/g °C

Explanation:

Step 1 : Write formule of specific heat

Q=mcΔT

with Q = heat transfer (J)

with m = mass of the substance

with c = specific heat ⇒ depends on material and phase ( J/g °C)

with ΔT = Change in temperature

For this case :

Q = 1680 Calories = 7033.824 J ( 1 calorie = 4.1868 J)

m = 100.0g

c= has to be determined

ΔT = 100 - 20 = 80°C

<u>Step 2: Calculating specific heat</u>

⇒ via the formule Q=mcΔT

7033.824 J = 100g * c * 80

7033.824 = 8000 *c

c = 7033.824 /8000

c = 0,879228 J/g °C

or 0.21 Cal / g°C

The specific heat of aluminium is 0.8792 J/g °C or 0.21 Cal/g °C

6 0

3 years ago