All categories

4 years ago

PLEASE HELP

Chemistry

2 answers:

Ipatiy [6.2K]4 years ago

6 0

Your answer should be “C.”

MARK ME BRAINLIEST PLEASE!!!!!!

dsp734 years ago

6 0

Answer:

The answer is C.

You might be interested in

A 642 mL sample of oxygen gas at 23.5°C and 795 mm Hg, is heated to 31.7°C and the volume of the gas expands to 957 mL. What is

Ratling [72]

We can use the combined gas law equation to find the new pressure of the gas.
$\frac{P1V1}{T1} = \frac{P2V2}{T2}$
where P - pressure
V - volume
T - temperature
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
P1 - 795 mm Hg x 0.0013 atm/ mm Hg = 1.033 atm
T1 - 23.5 °C + 273 = 296.5 K
T2 - 31.7 °C + 273 = 304.7 K
substituting the values in the equation
$\frac{1.033 atm *642 mL}{296.5K}= \frac{P*957mL}{304.7K}$
P = 0.712 atm
the answer closest to this value is A) 0.723 atm
therefore answer is
A) 0.723 atm

8 0

4 years ago

What is the atomic number of a sodium atom that has 11 protons and 12 neutrons?

galben [10]

Answer should be 23.

3 0

4 years ago

Working on-board a research vessel somewhere at sea, you have (carefully) isolated 12.5 micrograms (12.5 ×10–6 g) of what you ho

german

Answer:

The value is $Z = 311.33 \ g/mol$

Explanation:

From the question we are told that

The mass of saxitoxin is $m = 12.5 mg = 12.5 * 10^{-6} g$

The volume of water is $V = 3.10 mL = 3.10 *10^{-3} L$

The osmotic pressure is $P = 0.236 = \frac{0.236}{760} = 3.105 * 10^{-4} atm$

The temperature is $T = 19^oC = 19 + 273 = 292 \ K$

Generally the osmotic pressure is mathematically represented as

$P = C * T * R$

Here R is the gas constant with value

$R = 0.0821 ( L .atm /mol. K)$

and C is the concentration of saxitoxin

$3.105 * 10^{-4} = C * 0.0821 * 292$

$C = 1.295 *10^{-5} mol/L$

Generally the number of moles of saxitoxin is mathematically represented as

$n = C * V$

=> $n = 1.295 *10^{-5} *3.10 *10^{-3}$

=> $n = 4.015 *10^{-8} \ mol$

Generally the molar mass of saxitoxin is mathematically represented as

$Z = \frac{m}{n}$

=> $Z = \frac{12.5 * 10^{-6}}{ 4.015 *10^{-8}}$

=> $Z = 311.33 \ g/mol$

5 0

4 years ago

What is the molar mass of potassium bromide, KBR?

Nezavi [6.7K]

Answer:

id.............k

Explanation:

3 0

3 years ago

A 112 gram sample of an unknown metal was heated from 0.0C to 20.0C. The sample absorbed 1004 J of energy. What was the specific

worty [1.4K]

Answer:

The specific heat of the sample unknown metal is approximately 0.45 J/g °C.

General Formulas and Concepts:
Thermodynamics

Specific Heat Formula: $\displaystyle q = mc \triangle T$

m is mass (g)
c is specific heat capacity (J/g °C)
ΔT is the change in temperature

Explanation:

Step 1: Define

Identify variables.

m = 112 g

ΔT = 20.0 °C

q = 1004 J

Step 2: Solve for c

Substitute in variables [Specific Heat Formula]: $\displaystyle 1004 \ \text{J} = (112 \ \text{g})(c)(20.0 \ ^{\circ} \text{C})$
Simplify: $\displaystyle 1004 \ \text{J} = (2240 \ \text{g} \ ^\circ \text{C})c$
Isolate c: $\displaystyle c = 0.448214 \ \text{J} / \text{g} \ ^\circ \text{C}$
Round [Sig Figs]: $\displaystyle c \approx 0.45 \ \text{J} / \text{g} \ ^\circ \text{C}$

∴ specific heat capacity c is equal to around 0.45 J/g °C.

---

Topic: AP Chemistry

Unit: Thermodynamics

5 0

3 years ago