Q: 7.39 pm is equal to ________ nm.

$$7.39 \times 10$$^{-1}$$\ \mathrm{nm}$$

Question 1

Which of the following statements about elements, compounds, and mixtures is INCORRECT?

Accepted Answer

Sea water is a compound.

Question 2

What is the temperature difference of $$100\ ^\circ \mathrm{C}$$ when expressed in kelvins, $$K$$?

Accepted Answer

$$\Delta T = 100\ K$$

Question 3

7.39 pm is equal to ________ nm.

Accepted Answer

$$7.39 	imes 10$$^{-1}$$\ \mathrm{nm}$$

Question 4

352 g of two different liquids are poured into beakers. Liquid A has a much higher volume than liquid B. What can you conclude?

Accepted Answer

Liquid A must be less dense than liquid B.

Question 5

Perform the following calculation and provide the answer to the correct number of significant figures: $$25.45 \pm 0.45\ \mathrm{g} \div 73.55\ \mathrm{mL}$$

Accepted Answer

$$0.346\ \mathrm{g/mL}$$

Question 6

Which change is represented by the following scenario: a white solid and a liquid are mixed, and a homogeneous mixture forms?

Accepted Answer

A pure substance becoming a homogeneous mixture

Question 7

Which of the following statements is true?

Accepted Answer

[35Cl and 37Cl] are two isotopes of the same element, chlorine.

Question 8

The element X has two naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of element X is closest to:

Isotope | Mass (amu) | % Abundance
---|---|---
X-30 | 30.00 | 60.0
X-32 | 32.00 | 40.0

Accepted Answer

30.80

Question 9

Fill in the blanks indicated as (i) – (iv) in the following table. Note that the table works vertically. (i) is the symbol of a species with 34 p+, 46 n0, and 36 e–. (ii) is the number of neutrons in $$^{40}_{20}Ca$$^{2+}$$.

Accepted Answer

(i) $$^{80}_{34}Se$$^{2-}$$, (ii) 24

Question 10

Which of the following is the formula of hypochlorous acid?

Accepted Answer

$$\mathrm{HClO}$$

Question 11

Consider an ionic compound with the empirical formula of XPO$$_4$$ and molar mass of 121.95 g/mol, where X is a metallic element. What is the name of the compound?

Accepted Answer

Aluminum phosphate

Question 12

4.5725 $$	imes$$ $$10^{24}$$ atoms of a certain element weigh 819.0 g. What is the most likely identity of this element?

Accepted Answer

Copper

Question 13

The following are the first five compounds belonging to some of the simplest organic compounds, the alcohols:
CH$$_3OH
C$_2H$_5OH
C$_3H$_7OH
C$_4H$_9OH
C$_5H$_{11}OH

$$Choose the formula of an alcohol with seven carbon atoms, known as heptanol.

Accepted Answer

C$$_7H$_{15}OH$$

Question 14

What is the mass % of C in methanol, CH$$_3OH$$?

Accepted Answer

49.9%

Question 15

What is the sum of the stoichiometric coefficients when this equation is balanced using the smallest whole number coefficients?

$$\mathrm{$$HCO_3$$^-} + \mathrm{KOH} \rightarrow \mathrm{K_2CO_3} + \mathrm{H_2O}$$

Accepted Answer

14

Question 16

A sample of an unknown hydrocarbon undergoes complete combustion to produce 0.9931 g of CO$$_2$$ and 0.5078 g of H$$_2O. $$What is the empirical formula of the hydrocarbon?

Accepted Answer

CH

Question 17

Are the two molecules shown below isomers of each other? Justify your answer. (Butane and Cyclobutane)

Butane: $$\mathrm{CH_3CH_2CH_2CH_3}$$
Cyclobutane: $$\mathrm{C_4H_8}$$

Accepted Answer

No, because these molecules do not have the same molecular formula.

Question 18

The combustion of propane in the presence of excess oxygen yields carbon dioxide and steam:
$$\mathrm{C_3H_8(g) + 5 O_2$(g) \rightarrow 3 CO_2$(g) + 4 H_2O(g)}$$

When 2.5 mol of O$$_2$$ are consumed in this reaction, how many moles of CO$$_2$$ are produced?

Accepted Answer

1.5

Question 19

The reaction of ammonia with oxygen produces nitrogen dioxide and water according to the following reaction equation:
$$4\mathrm{NH_3$(g)} + 7\mathrm{O_2$(g)} \rightarrow 4\mathrm{NO_2$(g)} + 6\mathrm{H_2O(g)}$$

How much (in g) of nitrogen dioxide will be produced when 4.1 g of ammonia is reacted with 25 g of oxygen?

Accepted Answer

13.2 g

General Chemistry 1201: Study Notes for Chapters 1–3 (Matter, Atoms, and Stoichiometry)

Guida di studio - Domande di pratica

Study guide - Flashcard