39. which expression is represented by the model below?\n-6 -4 -2 0 2 4 6\na -5 + 0 c -5 + 3\nb -5 + 2 d -5…
39. which expression is represented by the model below?\n-6 -4 -2 0 2 4 6\na -5 + 0 c -5 + 3\nb -5 + 2 d -5 + 5\n40. the chemical name for salt is sodium chloride. its formula is nacl. in nacl, there is one sodium ion, na⁺, with a charge of +1, for every chlorine ion, cl⁻, with a charge of -1. what is the charge of nacl?\nf 0 h 2\ng 1 j 11\ncompare. use <, =, or >.\n41. -4 □ -10 42. -3 □ 3 43. 16 □ 23
Answer
39.
Explanation:
Step1: Analyze the number - line model
The starting point on the number - line is at - 5. The arrow moves 2 units to the right.
Step2: Determine the expression
Moving to the right on a number - line represents addition. So the expression is $-5 + 2$.
Answer:
B. $-5 + 2$
40.
Explanation:
Step1: Recall the rule of charge calculation in a compound
The charge of a compound is the sum of the charges of its ions. For $NaCl$, the charge of $Na^{+}$ is + 1 and the charge of $Cl^{-}$ is - 1.
Step2: Calculate the charge of $NaCl$
$+1+( - 1)=0$.
Answer:
F. 0
41.
Explanation:
Step1: Understand the rule for comparing negative numbers
On the number - line, a larger negative number is closer to 0. Since - 4 is closer to 0 than - 10, - 4 is greater than - 10.
Answer:
$-4>-10$
42.
Explanation:
Step1: Compare a negative and a positive number
Positive numbers are always greater than negative numbers. So - 3 is less than 3.
Answer:
$-3 < 3$
43.
Explanation:
Step1: Compare two positive numbers
When comparing two positive numbers, the larger number has a greater value. Since 16 is less than 23, 16 < 23.
Answer:
$16<23$