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1 year ago

A cup of hot water loses 265 cal

Chemistry

1 answer:

elixir [45]1 year ago

7 0

Answer:

-1071 Joules

Explanation:

The Joule was introduced as the SI unit for energy in 1925. One calorie is equal to approximately 4.184 joules(J). This is a conversion factor that we can write two ways:

(1cal/4.184J) or (4.184J/1cal)

(265 cal)*(4.184J/1cal) = 1071 J

Since the energy is leaving the system, it should be written with a minus sign: -1071J

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Please someone help me Balance this equation.

NeTakaya

Answer: This is an oxidation-reduction (redox) reaction:

3 C-II - 12 e- → 3 CII (oxidation)

4 CrVI + 12 e- → 4 CrIII (reduction)

C2H5OH is a reducing agent, K2Cr2O7 is an oxidizing agent.

7 0

2 years ago

If 23.5 g of magnesium occupies 13.5 cm^3 what is the density of magnesium

lara31 [8.8K]

The density of magnesium will be 1.74 g/cm³ if 23.5 g of magnesium occupies 13.5 cm³

<h3>What is Density ?</h3>

Density is the measurement of how tightly a material is packed together.

It is defined as the mass per unit volume.

Given ;

Mass = 23.5 g
Volume = 13.5 cm³

Formula to calculate density ;

Density = mass / volume

=23.5 / 13.5 = 1.74 g/cm³

Hence, the density of magnesium will be 1.74 g/cm³ if 23.5 g of magnesium occupies 13.5 cm³.

Learn more about density here ;

brainly.com/question/15164682

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4 0

1 year ago

Onsider the reaction below.

mamaluj [8]

Answer:

3.14 moles of hydrogen are produced

Explanation:

This is because for every 1 molesof hydrogen are produced 2 moles of oxygen are produced. So we take 6.28 divide it by 2 and we wend up with 3.14.

8 0

2 years ago

Compare how mammals care for their young with the other groups of animals.

slega [8]

Well, even though some baby mammals are born different ways, they all drink milk that comes from their mothers' bodies. Baby pigs, dolphins, bats and elephants all drink milk! Because the babies rely on their mother's milk to live, the mammalmommies have to care for their young.

4 0

2 years ago

Given the following: [G3P] = 1.5x10-5M; [BPG] = 3.0x10-3M ; [NAD+] = 1.2x10-5M; [NADH]=1.0x10-4 ; [HPO42-]= 1.2x10-5 M; pH = 7.5

mel-nik [20]

Answer: The given reaction is non-spontaneous in nature.

Explanation:

To calculate the $H^+$ concentration, we use the equation:

$pH=-\log[H^+]$

We are given:

pH of the solution = 7.5

$7.5=-\log [H^+]$

$[H^+]=10^{-7.5)=3.1\times 10^{-8}M$

For the given chemical equation:

$\text{Glyceraldehyde3-phosphate }+NAD^++HPO_4^{2-}\rightarrow \text{1,3-Biphosphoglycerate }+NADH+H^+$

The equation used to Gibbs free energy of the reaction follows:

$\Delta G=\Delta G^o+RT\ln K_{eq}$

where,

$\Delta G$ = free energy of the reaction

$\Delta G^o$ = standard Gibbs free energy = 6.3 kJ/mol = 6300 J/mol (Conversion factor: 1kJ = 1000J)

R = Gas constant = 8.314J/K mol

T = Temperature = $25^oC=[273+25]K=298K$

$K_{eq}$ = Ratio of concentration of products and reactants = $\frac{[BPG][NaDH][H^+]}{[G_3P][NAD^+][HPO_4^{2-}]}$

$[BPG]=3.0\times 10^{-3}M$

$[NADH]=1.0\times 10^{-4}M$

$[H^+]=3.1\times 10^{-8}M$

$[G_3P]=1.5\times 10^{-5}M$

$[NAD^+]=1.2\times 10^{-5}M$

$[HPO_4^{2-}]=1.2\times 10^{-5}M$

Putting values in above equation, we get:

$\Delta G=6300J/mol+(8.314J/K.mol\times 298K\times \ln (\frac{(3.0\times 10^{-3})\times (1.0\times 10^{-4})\times (3.1\times 10^{-8})}{(1.5\times 10^{-5})\times (1.2\times 10^{-5})\times (1.2\times 10^{-5})}))\\\\\Delta G=9917.02J/mol=9.92kJ/mol$

For the reaction to be spontaneous, the Gibbs free energy of the reaction must come out to be negative.

As, the Gibbs free energy of the reaction is positive. The reaction is said to be non-spontaneous.

Hence, the given reaction is non-spontaneous in nature.

4 0

2 years ago