Calculate the number of molecules?

Frost is dew that forms when the air temperature is______

SOVA2 [1]

The answer is B. Below freezing

6 0

3 years ago

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Q Q 3. (08.02 MC)

AnnyKZ [126]

Answer: A volume of 455 mL from 0.550 M KBr solution can be made from 100.0 mL of 2.50 M KBr.

Explanation:

Given: $V_{1}$ = ?, $M_{1}$ = 0.55 M

$V_{2}$ = 100.0 mL, $M_{2}$ = 2.50 M

Formula used to calculate the volume of KBr is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\0.55 M \times V_{1} = 2.50 M \times 100.0 mL\\V_{1} = 455 mL$

Thus, we can conclude that a volume of 455 mL from 0.550 M KBr solution can be made from 100.0 mL of 2.50 M KBr.

7 0

2 years ago

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Harry stores toxic chemical waste in a large steel tank that has only 15% of its volume underground. Jena lives in the wildernes

Anvisha [2.4K]

Answer:

Only Harry and Jena

Explanation:

Under federal regulations, an UST is any one or a combination of tanks such that the volume of an accumulation of regulated substances is 10% or more beneath the surface of the ground.

Any UST system holding a mixture of hazardous waste and other regulated substances are also are not covered by federal regulations regarding USTs.

Farm or residential tank of capacity more than 11 gallons used for storing motor fuel is covered by federal regulations regarding USTs.

According to the given question,

Only Harry and Jena are covered by federal regulations regarding USTs.

7 0

3 years ago

State whether the sign of the entropy change expected for each of the following processes will be positive or negative, and expl

Strike441 [17]

Answer:

a) ΔS is negative

b) ΔS is positive

c) ΔS is positive

d) ΔS is negative

Explanation:

Entropy (S) is a thermodynamic parameter which measures the randomness or the disorder in a system. Greater the disorder more positive will be the value of entropy.

The extent of disorder increases as substances transition from the solid to the gaseous state. i.e.

S(solid) < S(liquid) < S(gas)

The entropy change for a given reaction is:

$\Delta S = S(products)-S(reactants)----(1)$

a) $PCl3(l) + Cl2(g) \rightarrow PCl5(s)$

Here the reactants are in the liquid and gas phase which have higher entropy than the product which is in the solid phase i.e. lower entropy.

Since S(product) < S(reactant), based on equation 1, ΔS will be negative.

b) $2HgO(s) \rightarrow 2Hg(l) + O2(g)$

Here the products are in the liquid and gas phase which have higher entropy than the reactant which is in the solid phase i.e. lower entropy.

Since S(product) > S(reactant), based on equation 1, ΔS will be positive.

c) $H2(g) \rightarrow 2H(g)$

Here the products and reactants are in the gas phase. However the number of moles of products is greater than the reactants

Since S(product) > S(reactant), based on equation 1, ΔS will be positive.

d) $U(s) + 3F2(g) \rightarrow UF6(s)$

Here one of the reactants is in the gas phase which corresponds to a more positive entropy compared to the product which is in the solid phase i.e. lower entropy.

Since S(product) < S(reactant), based on equation 1, ΔS will be negative.

8 0

2 years ago

Which is a characteristic of an Atoms

Rama09 [41]

Answer:

2. they are the smallest unit of matter

6 0

2 years ago