Which one of the following is not equal to 100 meters

What do columns on the periodic table tell us?

AfilCa [17]

Answer:

Column on the periodic table tell the number of valence electrons and the types of chemicals, such as metals, nonmetals, alkaline earth metals, metalloids, halogens, noble gases.

Explanation:

3 0

3 years ago

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Which of the following is unrelated to estimating vapor pressure? (a) Antoine's Equation (b) Cox charts (c) Gibb's phase rule (d

Bezzdna [24]

Answer:

(c) Gibb's phase rule

Explanation:

Gibb's phase rule :

describe the relationship between the number of degrees fredoom in a closed system, the number of phases in equilibrium and the number of the system components.

f = c - p + 2

the above is no related to the estimation of the vapor pressure.

3 0

3 years ago

ombustion reactions involve reacting a substance with oxygen. When compounds containing carbon and hydrogen are combusted, carbo

Bad White [126]

Explanation:

The given reaction is as follows.

$C_{4}H_{4}(g) + 2H_{2}(g) \rightarrow C_{4}H_{8}(g)$

So, enthalpy change for the given reaction is calculated as follows.

$\Delta H_{rxn} = \sum n \Delta H_{products} - \sum n \Delta H_{reactants}$

where, n = number of moles.

Now, putting the given values into the above equation and calculate the change in enthalpy as follows.

$\Delta H_{rxn} = \sum (1 mol C_{4}H_8(g)) \times (-2755 kJ / mol) - \sum (2 mol H_2(g)) \times (-286 kJ/mol) + (1 mole C_4H_4(g)) \times (-2341 kJ/mole)$

= $\sum -2755 kJ - \sum -2913 kJ)$

= 158 kJ

Thus, we can conclude that enthalpy of the combustion is 158 kJ.

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3 years ago

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What is the rate constant of a first-order reaction that takes 563 secondsseconds for the reactant concentration to drop to half

Stella [2.4K]

Answer: The rate constant of a first-order reaction that takes 563 secondsseconds for the reactant concentration to drop to half of its initial value is $1.23\times 10^{-3}s^{-1}$

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

$k=\frac{0.693}{563s}=1.23\times 10^{-3}s^{-1}$

Thus rate constant of a first-order reaction that takes 563 secondsseconds for the reactant concentration to drop to half of its initial value is $1.23\times 10^{-3}s^{-1}$

4 0

3 years ago

Tantalum is an element used, among other things, in making aircraft parts. Suppose the properties of a tantalum part are being t

-BARSIC- [3]

Answer:

30

Explanation:

it is what it is

8 0

3 years ago