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3 years ago

Polished metals have a metallic luster, which means that?

1 answer:

7 0

Metallic luster refers to the way light casts off of a mineral. Polished metals such as gold have a metallic luster, which makes them look bright and shiny, and reflect more light than other minerals. There are also minerals that have metallic luster, but are not shiny or reflect much light, which is called dull metallic luster.

Metallic luster - bright, shiny
Dull metallic luster - not shiny

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The tendency for an object at rest to remain at rest is?

cestrela7 [59]

Newtons First Law... Newton's first law of motion - sometimes referred to as the law of inertia. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

6 0

4 years ago

Penicillin is hydrolyzed and thereby rendered inactive by penicillinase, an enzyme present in some resistant bacteria. The mass

Arisa [49]

Answer:

The turnover number is the maximum substrate quantitiy converted to product per enzyme and per second. It can be calculate as follows:

$k_c = \frac{V_{max}}{[E]}$ with $[E]$ active enzyme concentration.

In this case we have Vmax an data to calculate $[E]$

$moles of E=\frac{10^{-9}g}{29600 g/mol}=3.38*10^{-14}$

$[E]=\frac{3.38*10^{-14}}{0.01 L}=3.38*10^{-12} M$

Now $k_c=\frac{6.8*10^-10}{3.38*10^{-12}}=201.28 min^{-1}$

it is not like any option.

If we assume that $V_{max}$ have the non usual units of $mol L^{-1} min^{-1}$ and it is $6.8*10^-10 mol min^{-1}$

So we need divide by the moles of E (in place of [E])

Now $k_c=\frac{6.8*10^-10}{3.38*10^{-14}}=20128 min^{-1} = 335 s{-1}$

(pass from $min^{-1}$ to $s^{-1}$ dividing by 60)

4 0

3 years ago

Which statement is correct about the theory of combustion? (1 point)

Vadim26 [7]

Answer:

i need the answer

Explanation:

6 0

2 years ago

A soft drink contains 12.1% sucrose (C12H22O11) by mass. What volume of the soft drink solution in milliliters contains 102.5 g

galina1969 [7]

The volume of the soft drink solution in milliliters that contains 102.5 g of sucrose is 11.93mL.

<h3>How to calculate volume?</h3>

The volume of a solution can be calculated by dividing the mass by the density. That is;

Volume = mass/density

According to this question, a soft drink contains 12.1% sucrose (C12H22O11) by mass. This means that the mass of the sucrose is

12.1/100 × 102.5 = 12.40g of sucrose

Volume = 12.40g ÷ 1.04g/mL

Volume = 11.93mL

Therefore, the volume of the soft drink solution in milliliters that contains 102.5 g of sucrose is 11.93mL.

Learn more about volume at: brainly.com/question/1578538

4 0

3 years ago

The catalytic decomposition of hydrogen peroxide yields oxygen gas and water, according to the reaction given below. In an exper

elixir [45]

Answer:

The molar concentration of hydrogen peroxide is 0.01164 M

Explanation:

Step 1: Data given

Volume of gas yielded = 75.3 mL = 0.0753 L

Temperature = 25.0 °C

Atmosphere = 0.976 atm

(Water = 0.032 atm at 25°C)

The original volume of H2O2 is 500 mL

Molar mass of O2 =32 g/mol

Step 2: The balanced equation

2H2O2(aq) → 2 H2O(l) + O2(g)

Step 3: Calculate pressure of O2

P = P(02) + P(water)

P(O2) = P - P(water)

P(O2) = 0.976 atm - 0.032 atm

P(O2) = 0.944 atm

Step 4: Calculate moles O2

p*V=n*R*T

⇒ with p = the pressure of O2 gas = 0.944 atm

⇒ with V= the volume of O2 = 0.0753 L

⇒ with n = the number of moles of O2

⇒ with R = the gas constant = 0.08206 L*atm/K*mol

⇒ with T = the temperature = 25°C = 298 Kelvin

n = (p*V)/(R*T)

n = (0.944 * 0.0753)/(0.08206*298K)

n = 0.00291 moles O2

Step 5: Calculate moles of H2O2

For 1 mole of O2 produced, we need 2 moles of H2O2

For 0.00291 moles O2 we need 2*0.00291 = 0.00582 moles H2O2

Step 6: Calculate molar concentration of H2O2

Molar concentration = moles / volume

Molar concentration = 0.00582 moles / 0.500L

Molar concentration = 0.01164 M

The molar concentration of hydrogen peroxide is 0.01164 M

3 0

3 years ago