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2 years ago

Speed is defined as __________.

Chemistry

1 answer:

MariettaO [177]2 years ago

6 0

Answer:D)

Explanation: the distance traveled over time

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Calculate the mass (grams) of 0.750 moles of Al2(Cr2O7)3

garik1379 [7]

Answer:

526g is the mass of this sample

Explanation:

To solve this question we must, as first, find the <em>molar mass </em>of Al₂(Cr₂O₇)₃ using the periodic table. The molar mass is defined as the mass of this compound per mole. With this value we can find the mass in 0.750 moles as follows:

<em>Molar mass Al₂(Cr₂O₇)₃</em>

2Al = 2*26.98g/mol = 53.96g/mol

6 Cr = 6*51.9961g/mol = 311.9766g/mol

21 O = 21*15.999g/mol = 335.979g/mol

53.96g/mol + 311.9766g/mol + 335.979g/mol

= 701.9156g/mol

The mass of 0.750 moles is:

0.750 moles * (701.9156g / mol) =

<h3>526g is the mass of this sample</h3>

8 0

2 years ago

Please help!

ANEK [815]

Answer:

A- Physical, B- Chemical, C- chemical, D- Physical

Explanation:

A is physical because you can see it changing its form is changing.

B is Chemical because a new substance is formed creating the orange color of rust.

C is a Chemical reaction because it is being broken down so the banana itself is changing not just how we see it.

D is physical because we are just changing the shape/ size of the item, not anything to do with its substances.

8 0

2 years ago

Read 2 more answers

For each phenotype, write the possible genotypes.

Citrus2011 [14]

Answer:

Tall, Res, Dom

short, RES, RES

3 0

3 years ago

Which solution has the greatest buffer capacity? Select the correct answer below: 1 mole of acid and 1 mole of base in a 1.0 L s

Lorico [155]

Answer:

The answer is

Explanation:

1 mole of acid.

Hope this helps....

Have a nice day!!!!

8 0

3 years ago

A helium-filled balloon at 310.0 K and 1 atm, contains 0.05 g He, and has a volume of 1.21 L. It is placed in a freezer (T = 235

trapecia [35]

Answer : The value of $\Delta E$ of the gas is 2.79 Joules.

Explanation :

First we have to calculate the moles of helium.

$\text{Moles of helium}=\frac{\text{Mass of helium}}{\text{Molar mass of helium}}$

Molar mass of helium = 4 g/mole

$\text{Moles of helium}=\frac{0.05g}{4g/mole}=0.0125mole$

Now we have to calculate the heat.

Formula used :

$q=nc_p\Delta T\\\\q=nc_p(T_2-T_1)$

where,

q = heat

n = number of moles of helium gas = 0.0125 mole

$c_p$ = specific heat of helium = 20.8 J/mol.K

$T_1$ = initial temperature = 310.0 K

$T_2$ = final temperature = 235.0 K

Now put all the given values in the above formula, we get:

$q=nc_p(T_2-T_1)$

$q=(0.0125mole)\times (20.8J/mol.K)\times (235.0-310.0)K$

$q=-19.5J$

Now we have top calculate the work done.

Formula used :

$w=-p\Delta V\\\\w=-p(V_2-V_1)$

where,

w = work done

p = pressure of the gas = 1 atm

$V_1$ = initial volume = 1.21 L

$V_2$ = final volume = 0.99 L

Now put all the given values in the above formula, we get:

$w=-p(V_2-V_1)$

$w=-(1atm)\times (0.99-1.21)L$

$w=0.22L.artm=0.22\times 101.3J=22.29J$

conversion used : (1 L.atm = 101.3 J)

Now we have to calculate the value of $\Delta E$ of the gas.

$\Delta E=q+w$

$\Delta E=(-19.5J)+22.29J$

$\Delta E=2.79J$

Therefore, the value of $\Delta E$ of the gas is 2.79 Joules.

3 0

3 years ago