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3 years ago

Which of the following is an example of a physical change?

Chemistry

2 answers:

dangina [55]3 years ago

5 0

D it is only physical and not chemical

mars1129 [50]3 years ago

4 0

Answer:

Explanation:

Because a physical change is affecting the form of a chemical substance, not its chemical composition.

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2Na2SO4 :How many atoms for each element are in the formula?<br><br> S=<br> O=<br> Na=

yuradex [85]

Answer:

S= 2(1) = 2

O= 2(4) = 8

Na= 2(2) = 4

Explanation:

The given compound is:

2Na₂SO₄

An element is a distinct substance that cannot be split up into simpler substances.

So;

Number of atoms of elements here are:

S= 2(1) = 2

O= 2(4) = 8

Na= 2(2) = 4

6 0

2 years ago

The value of Kp for the reaction NO(g) 1 1 2 O2(g) 4 NO2(g) is 1.5 3 106 at 25°C. At equilibrium, what is the ratio of PNO2 to P

expeople1 [14]

Answer : The ratio of $p_{NO_2}$ to $p_{NO}$ is, $6.87\times 10^5$

Solution : Given,

$K_p=1.5\times 10^6$

$p_{O_2}$ = 0.21 atm

The given equilibrium reaction is,

$NO(g)+\frac{1}{2}O_2\rightleftharpoons NO_2(g)$

The expression of $K_p$ will be,

$K_p=\frac{(p_{NO_2})}{(p_{NO})\times (p_{O_2})^{\frac{1}{2}}}$

Now put all the given values in this expression, we get:

$1.5\times 10^6=\frac{(p_{NO_2})}{(p_{NO})\times (0.21)^{\frac{1}{2}}}$

$\frac{(p_{NO_2})}{(p_{NO})}=(1.5\times 10^6)\times (0.21)^{\frac{1}{2}}$

$\frac{(p_{NO_2})}{(p_{NO})}=6.87\times 10^5$

Therefore, the ratio of $p_{NO_2}$ to $p_{NO}$ is, $6.87\times 10^5$

5 0

3 years ago

(Yield Problem)

alex41 [277]

Answer:

Percent Yield Fe = 82.5%

Explanation:

The actual yield is the value produced after an experiment is conducted. The theoretical yield is the value calculated using the balanced chemical equation and atomic/molar masses.

To find the percent yield of iron (Fe), you need to (1) convert grams Al to moles Al (via atomic mass), then (2) convert moles Al to moles Fe (via mole-to-mole ratio from equation coefficients), then (3) convert moles Fe to grams Fe (via atomic mass), and then (4) calculate the percent yield. It is important to arrange the ratios in a way that allows for the cancellation of units. The final answer should have 3 sig figs to reflect the sig figs of the given values.

Atomic Mass (Mg): 24.305 g/mol

Atomic Mass (Fe): 55.845 g/mol

3 Mg + 2 FeCl₃ -----> 2 Fe + 3 MgCl₂

20.5 g Mg 1 mole 2 moles Fe 55.845 g
----------------- x ----------------- x ---------------------- x ----------------- =
24.305 g 3 moles Mg 1 mole

= 31.4 g Fe

Actual Yield
Percent Yield = ---------------------------------- x 100%
Theoretical Yield

25.9 g Fe
Percent Yield = -------------------- x 100%
31.4 g Fe

Percent Yield = 82.5%

5 0

1 year ago

Muscle Activity

sasho [114]

I’m pretty sure it would be B

7 0

2 years ago

Read 2 more answers

Which is a characteristic of a strong base

Lubov Fominskaja [6]

Answer:

Explanation:

The strong bases have following properties:

1. In solution, strong bases ionize fully.

2. On dissolving the strong bases in water they produce all hydroxide ion which they have.

3. For strong bases the value of equilibrium constant (Kb ) is large.

4. In general the strong base ionizes completely means concentration of ions are greater means conductivity also greater.

5. For strong bases the value of equilibrium constant (Kb) is large, thus the value of dG0 is very large negative number.

6 0

2 years ago