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Martin slowly pours an unknown liquid into a container that originally had some water in it. He is measuring the temperature in

lora16 [44]

B. a chemical change

8 0

3 years ago

Read 2 more answers

How many moles are in 3.57 x 10 32 particles Ca?

valentina_108 [34]

Answer:

$\boxed {\boxed {\sf 592,826,303.6 \ moles \ of \ Ca }}$

Explanation:

To convert from moles to particles, we must Avogadro's Number.

$6.022*10^{23}$

This number tells us the number of particles (atoms, ions, molecules, etc.) in 1 mole of a substance. In this case, it is the particles of calcium in 1 mole of calcium.

$6.022*10^{23} \ particles \ Ca / mole \ Ca$

We can use Avogadro's Number as a ratio or fraction.

$\frac{6.022 *10^{23} \ particles \ Ca}{1 \ mol \ Ca}$

Multiply this by the given number of particles (3.57*10³²).

$3.57*10^{32} \ particles \ Ca*\frac{6.022 *10^{23} \ particles \ Ca}{1 \ mol \ Ca}$

Flip the fraction so the particles of calcium will cancel out.

$3.57*10^{32} \ particles \ Ca*\frac{1 \ mol \ Ca}{6.022 *10^{23} \ particles \ Ca}$

$3.57*10^{32} *\frac{1 \ mol \ Ca}{6.022 *10^{23} }$

$\frac{3.57*10^{32} \ mol \ Ca}{6.022 *10^{23} }$

$592826303.6 \ mol \ Ca$

There are 592,826,303.6 moles of calcium in 3.57*10³² particles of calcium.

8 0

3 years ago

Find the volume of 6.45 moles of gas present at a temperature of 27.0oC and a pressure of 675 torr.

maw [93]

Answer: The volume of the gas is 178.76 L

Explanation:

The ideal gas equation is given as:

.......(1)

where

P = pressure of the gas = 675 torr

V = volume of gas = ?

n = number of moles of gas = 6.45 moles

R = Gas constant = 62.36 L.torr/mol.K

T = temperature of the gas = $27^oC=[27+273]K=300K$

Putting values in equation 1, we get:

$675torr\times V=6.45mol\times 62.36L.torr/mol.K\times 300K\\\\V=\frac{6.45\times 62.36\times 300}{675}=178.76 L$

Hence, the volume of the gas is 178.76 L

3 0

4 years ago

Ethanol is added to gasoline because the oxygen it contains improves gasoline's burning efficiency. Its combustion reaction is g

Angelina_Jolie [31]

Answer:

A) Exothermic

B) (1) -410.5 kJ (2) -98.1 kcal

C) -976.44 kJ

Explanation:

A) By the value of ΔH (-1236 kJ), we can see that it's negative, it means that the heat is being lost by the reaction, and, because of that, the reaction is exothermic.

B) The molar mass of ethanol is 46.07 g/mol, so, at 15.3 grams, the number of moles is:

n = mass/molar mass

n = 15.3/46.07

n = 0.3321 mol

By the equation

1 mol of ethanol ----------------------- -1236 kJ

0.3321 mol of ethanol ----------------------- x

By a simple direct three rule:

x = -410.5 kJ

1 kJ --------------- 0.2390 kcal

-410 kJ ---------- y

y = -98.10 kcal

C) The molar mass of water is 18 g/mol, so the number of moles at 42.7 g is:

n = 42.7/18

n = 2.37 moles

By the equation

3 moles of water ----------------------- -1236 kJ

2.37 moles of water --------------------- x

By a simple direct three rule:

3x = -2929.32

x = -976.44 kJ

5 0

3 years ago

What does it mean if a solution is a "weak acid "? Strong acid? Give logical ph values for each

galina1969 [7]

Answer:

A weak acid is an acid that partially dissociates into its ions in an aqueous solution or water. In contrast, a strong acid fully dissociates into its ions in water. At the same concentration, weak acids have a higher pH value than strong acids.

Explanation:

:)

5 0

3 years ago