Please help due tomorrow science

Chemistry

1 answer:

horrorfan [7]3 years ago

8 0

Answer:

1. start line drawn in ink

2. start line below solvent level

Explanation:

1. the line would run up the paper. should have drawn with pencil.

2. the samples would dissolve into solvent and not run up the paper.

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A solution of ammonia and water contains 2.10×1025 water molecules and 7.10×1024 ammonia molecules. How many total hydrogen atom

Natali5045456 [20]

There are 6.33 × 10²⁵ hydrogen atoms in this solution in total.

<h3>Explanation</h3>

There are two hydrogen atoms in each water $\text{H}_2\text{O}$ molecule.
There are three hydrogen atoms in each ammonia $\text{NH}_3$ molecule.

2.10 × 10²⁵ water molecules and 7.10 × 10²⁴ ammonia molecules will contain

$2 \times 2.10 \times 10^{25} + 3 \times 7.10 \times 10^{24} = 6.33 \times 10^{25}$ hydrogen atoms in total.

8 0

3 years ago

a 1.642 g sample of calcium bromide is dissolved in enough water to give 469.1 mL of solution what is the bromide ion concentrat

aleksklad [387]

The bromide concentration in this solution of calcium bromide dissolved in enough water to give 469.1 mL is 1.75 × 10-⁵M.

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

The concentration of a solution can be calculated by dividing the number of moles of the substance by its volume.

No of moles of calcium bromide is calculated as follows:

moles = 1.642 ÷ 199.89 = 8.215 × 10-³moles

Molarity = 8.215 × 10-³moles ÷ 469.1mL = 1.75 × 10-⁵M

Therefore, the bromide concentration in this solution of calcium bromide dissolved in enough water to give 469.1 mL is 1.75 × 10-⁵M.

Learn more about concentration at: brainly.com/question/10725862

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4 0

2 years ago

Give the nuclear symbol for the isotope of silicon for which a=29? Enter the nuclear symbol for the isotope (e.G., 42he).

quester [9]

The mass number is the summation of number of proton and neutron present in a nucleus of an atom. For the neutral atom the number of positive charge (number of proton) must be equal to the number of electrons. The number of electrons present in an atom is the atomic number of the atom. The standard way to express the mass number (a) and atomic number (m) of a atom (say X) is $x^{a}_{m}$ . Now for silicon number of electron or atomic number is 14. And the mass number (a) given 29. Thus the expression nucleus of silicon will be $Si^{29}_{14}$