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3 years ago

Express the following number in scientific notation. 0.53000 = _____

2 answers:

8 0

Well the zeros after the decimal dot and after any decimal whole number is not count so the correct answer can be the first one (I hope this can help you a little bit)

kakasveta [241]3 years ago

7 0

Yes, it would be the last one as the zeros that appear after a non zero number are significant.

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(( PLEASE HELP QUICK ))Which expression can be used to calculate the ratio of the rate of effusion of gas A to the rate of effus

borishaifa [10]

Answer:

The square root of the molar mass of B ÷ the square root of the molar mass of A

Explanation:

Graham’s Law applies to the effusion of gases:

The rate of effusion (r) of a gas is inversely proportional to the square root of its molar mass (M).

$r \propto \dfrac{1}{\sqrt{M}}$

If you have two gases A and B, the ratio of their rates of effusion is

$\dfrac{r_{\text{A}}}{r_{\text{B}}} = \sqrt{\dfrac{M_{\text{B}}}{M_{\text{A}}}}$

3 0

3 years ago

His transmitter is mostly located in diffuse neuronal systems in the CNS, with cell bodies particularly in the raphe nuclei. It

joja [24]

Answer: The correct answer is a) Acetylcholine.

Explanation:

The acetylcholine is a very important neurotransmitter involved in the mediation of synaptic activity between neurons. Among its most important functions we find: expression of mood states, vasodilation, gastrointestinal motility, bronchoconstriction, circular iris muscle contraction and sweat gland secretion.

Therefore the correct answer is a) Acetylcholine.

8 0

3 years ago

A 1.0 g sample of hydrogen reacts completely with 19.0 g of fluorine to form a compound of hydrogen and fluorine. a. What is the

Rashid [163]

Explanation:tr

a) Molar mass of HF = 20 g/mol

Atomic mass of hydrogen = 1 g/mol

Atomic mass of fluorine = 19 g/mol

Percentage of an element in a compound:

$\frac{\text{Number of atoms of element}\times \text{Atomic mass of element}}{\text{Molar mass of compound }}\times 100$

Percentage of fluorine:

$\frac{1\times 19 g/mol}{20g/mol}\times 100=95\%$

Percentage of hydrogen:

$\frac{1\times 1g/mol}{20 g/mol}\times 100=5\%$

b) Mass of hydrogen in 50 grams of HF sample.

Moles of HF = $\frac{50 g}{20 g/mol}=2.5 mol$

1 mole of HF has 1 mole of hydrogen atom.

Then 2.5 moles of HF will have:

$1\times 2.5 mol=2.5 mol$ of hydrogen atom.

Mass of 2.5 moles of hydrogen atom:

1 g/mol × 2.5 mol = 2.5 g

2.5 grams of hydrogen would be present in a 50 g sample of this compound.

c) As we solved in part (a) that HF molecules has 5% of hydrogen by mass.

Then mass of hydrogen in 50 grams of HF compound we will have :

5% of 50 grams of HF = $\frac{5}{100}\times 50 g=2.5 g$

8 0

3 years ago

Describe the three types of system: a.open: b.closed: c. Isolated:

Mnenie [13.5K]

An open system is when there is a transfer of energy and matter with its surroundings.

A closed system is where there is a transfer of energy, may it be heat or work, but not matter with its surroundings.

An isolated system is where there is no transfer of energy or matter with its surroundings.

4 0

2 years ago

Can you please help

zysi [14]

Answer:

a. NH2CH2COOH

b. The function group is what I put in bold.

c. carboxylic acid and amine

10.

a. NH2CH(CH3)COOH

b. The functional group is in bold.

c. carboxylic acid and amine

Explanation:

NH2 is amine (amino acid)

COOH is the carboxylic acid (acetic acid)

8 0

2 years ago